4l80e tear down and rebuild
- Thread starter Quickstop [UK]
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Quickstop [UK]
Combating adversyty.
Re: 4l80e tear down and rebuild
I don't really know enough about transmissions so appreciate the input. All advice I have read on this so far suggests plugging the hole so you are the first to disagree. You make a strong case however.,
That said, as far as the line pressure not being a problem, brake lines don't do so well with even tiny holes in them so I want to be careful. I'd rather ask the question. As usual, I am doing this by myself with noone experienced around, based off hearsay on the internet.
Probably. Like you say, it looks pretty easy to close up.
It was pretty tight putting it back in the case so I hope it's ok. There didn't seem any excess play at least and there are no leaks now.
So...
I thought I'd update a little for anyone curious...
Basically, I got it back together...
My new torque converter arrived so spurred me on:
In comparison to the new on the left, old on the right..
Assembly was pretty easy because the clutch packs weren't disassembled. There was no indication to do so. The fluid was clear and there was no debris in the pan, the filter or anywhere in the valve body.
Some of the clutch assemblies were a bit fiddly to install and line up:
If I were to do this again, I'd get a couple of specialist tools. The 4th clutch assembly tool is pretty much essential. (J38731). I didn't take the 4th clutch apart as I had OD on the motorway but this tool is one that you can't really do without.
Dropping the clutch assemblies into the upright case was also tricky. There is a tool which fits around the neck of the inbput shaft which is bascally a piece of metal with a notch. I managed but it was harder than it needed to be.
Overall the case and trans are really easy to work on. It's all modular, the guidelines are easily available and the parts are available.
This is the old shaft. This would have broken in the not too distant future.
I didn't find anything wrong so put the new (used) 4x4 output shaft in and it all went together fine in the end.
The Bad News
I got the trans back in the truck after assembling the transfer case with the new shaft (a beautiful item from SpeedInc.com[link to build])
Unfortunately, I had exactly the same problem as before so I am now focussed on the controller. I have reverse but in OD, the truck needs a lot of revs before it goes anywhere. I can't get it on the road to test the other gears so need to see if I can command 1st via the controller. It's so frustrating. :tdown: It seems like it is in limp mode so my efforts wil be directed that way.
But, at least the truck is assembled and can be moved around and I know that the clutches are ok in the trans and there is no junk. I also know my output shaft won't twist off in the future.
I just wish I knew what the problem was, then I could fix it.
You have to laugh though right?
I don't really know enough about transmissions so appreciate the input. All advice I have read on this so far suggests plugging the hole so you are the first to disagree. You make a strong case however.,
That said, as far as the line pressure not being a problem, brake lines don't do so well with even tiny holes in them so I want to be careful. I'd rather ask the question. As usual, I am doing this by myself with noone experienced around, based off hearsay on the internet.
Probably. Like you say, it looks pretty easy to close up.
It was pretty tight putting it back in the case so I hope it's ok. There didn't seem any excess play at least and there are no leaks now.
So...
I thought I'd update a little for anyone curious...
Basically, I got it back together...
My new torque converter arrived so spurred me on:
In comparison to the new on the left, old on the right..
Assembly was pretty easy because the clutch packs weren't disassembled. There was no indication to do so. The fluid was clear and there was no debris in the pan, the filter or anywhere in the valve body.
Some of the clutch assemblies were a bit fiddly to install and line up:
If I were to do this again, I'd get a couple of specialist tools. The 4th clutch assembly tool is pretty much essential. (J38731). I didn't take the 4th clutch apart as I had OD on the motorway but this tool is one that you can't really do without.
Dropping the clutch assemblies into the upright case was also tricky. There is a tool which fits around the neck of the inbput shaft which is bascally a piece of metal with a notch. I managed but it was harder than it needed to be.
Overall the case and trans are really easy to work on. It's all modular, the guidelines are easily available and the parts are available.
This is the old shaft. This would have broken in the not too distant future.
I didn't find anything wrong so put the new (used) 4x4 output shaft in and it all went together fine in the end.
The Bad News
I got the trans back in the truck after assembling the transfer case with the new shaft (a beautiful item from SpeedInc.com[link to build])
Unfortunately, I had exactly the same problem as before so I am now focussed on the controller. I have reverse but in OD, the truck needs a lot of revs before it goes anywhere. I can't get it on the road to test the other gears so need to see if I can command 1st via the controller. It's so frustrating. :tdown: It seems like it is in limp mode so my efforts wil be directed that way.
But, at least the truck is assembled and can be moved around and I know that the clutches are ok in the trans and there is no junk. I also know my output shaft won't twist off in the future.
I just wish I knew what the problem was, then I could fix it.
You have to laugh though right?
Quickstop [UK]
Combating adversyty.
Re: 4l80e tear down and rebuild
I had a chance over the weekend to look into the trans a bit more or at least mess around with it thanks to my Dad. I was on the phone with him from London while he worked on it in Cornwall. 300 miles separation.
He was able to set up a laptop to the PCS unit and also run through the gears with the truck on axle stands - where else right? :rotf:
So... first off, the PCS controller won't connect to his laptop so it wasn't possible to datalog. I was connected via TeamViewer to the laptop and no amount of improvisation helped. I was able to with my laptop so I hope it is just a software conflict. I may be able to send it off as PCS will inspect it and repair it free of charge. I am pretty impressed with their service support.
At this point, he disconnected the controller and was again able to isolate solenoid A and B wires. They would click on and off audibly.
So to recap:
Reverse is ok so the pump is working. It does need a decent amount of revs though and on a hill, it will slip forward. Is this normal in an 80e? I thought the sprags and clutches prevented it from rolling backwards?
1st gear - not apparent.
2nd gear - if I rev the truck, it pulls forward. I assume this is second.
3rd - no sign of third
4th - 4th wasn't there without the TCC lockup.
So...
According to the logic table, if I have second, the Overdrive Clutch and the Forward clutch are applied. In 1st, the only difference is the low roller clutch should be holding. It overruns in every other gear. That might explain why 1st is gone.
3rd and fourth are harder to explain. Does the TCC cause the OD to use the clutches differently? Otherwise, I should have Third. Direct clutch is applied in REV so I know that works.
Does OD only happen with TCC apply?
I am so confused. :dunno:
I need to send the PCS unit for testing on the off-chance that it is defective but I honestly don't expect much to come of that. I think it is fine.
I am coming round to the idea that the valve body is messed up or that a seal has blown in one or more clutches. I am going to order a transmission pressure gauge tester and see what I get. A blown seal could explain it, or at least part of it. I looked at the valve body though and the valves didn't seem stuck and the fluid was immaculate.
There is an 80e in the UK for £400 shipped. I am kind of thinking of buying it to fall back on. I can't see myself figuring out this one in a hurry. Replacing the converter and having to do the transfer case rebuild and now possibly the trans ... this is ridiculous.
I WISH I had air checked the clutches when I reassembled the trans. Oh well.. another lesson learned.
I could really do with some ideas here folks. Am really jaded about the truck right now. :tdown:
I had a chance over the weekend to look into the trans a bit more or at least mess around with it thanks to my Dad. I was on the phone with him from London while he worked on it in Cornwall. 300 miles separation.
He was able to set up a laptop to the PCS unit and also run through the gears with the truck on axle stands - where else right? :rotf:
So... first off, the PCS controller won't connect to his laptop so it wasn't possible to datalog. I was connected via TeamViewer to the laptop and no amount of improvisation helped. I was able to with my laptop so I hope it is just a software conflict. I may be able to send it off as PCS will inspect it and repair it free of charge. I am pretty impressed with their service support.
At this point, he disconnected the controller and was again able to isolate solenoid A and B wires. They would click on and off audibly.
So to recap:
Reverse is ok so the pump is working. It does need a decent amount of revs though and on a hill, it will slip forward. Is this normal in an 80e? I thought the sprags and clutches prevented it from rolling backwards?
1st gear - not apparent.
2nd gear - if I rev the truck, it pulls forward. I assume this is second.
3rd - no sign of third
4th - 4th wasn't there without the TCC lockup.
So...
According to the logic table, if I have second, the Overdrive Clutch and the Forward clutch are applied. In 1st, the only difference is the low roller clutch should be holding. It overruns in every other gear. That might explain why 1st is gone.
3rd and fourth are harder to explain. Does the TCC cause the OD to use the clutches differently? Otherwise, I should have Third. Direct clutch is applied in REV so I know that works.
Does OD only happen with TCC apply?
I am so confused. :dunno:
I need to send the PCS unit for testing on the off-chance that it is defective but I honestly don't expect much to come of that. I think it is fine.
I am coming round to the idea that the valve body is messed up or that a seal has blown in one or more clutches. I am going to order a transmission pressure gauge tester and see what I get. A blown seal could explain it, or at least part of it. I looked at the valve body though and the valves didn't seem stuck and the fluid was immaculate.
There is an 80e in the UK for £400 shipped. I am kind of thinking of buying it to fall back on. I can't see myself figuring out this one in a hurry. Replacing the converter and having to do the transfer case rebuild and now possibly the trans ... this is ridiculous.
I WISH I had air checked the clutches when I reassembled the trans. Oh well.. another lesson learned.
I could really do with some ideas here folks. Am really jaded about the truck right now. :tdown:
MadMike
Member
Re: 4l80e tear down and rebuild
I feel for ya man... about how mine turned out. I know that book has a bad or hard to tell pic of the sprag and which way it goes. Just a thought. Been a year since I had my head in that mode. Also the servos are known to be weak and crack. If ur in there I'd replace all the electric components and those servos. About 150 for the electric s over here.
And remember even guys that do it daily need to do it more than once to get them right. I had mine apart and together atleast 4 5 times before I gave up. By the end I could do it in 20 min. Took it in finally and all it was was the sprag. I have completely tore is down n assembled all those times n was that stupid pic in the book. My condition was super super loose convertor n then it seemed like 2nd was fine. Obviously I'm not a trans tech but I would do it again. Hang in there.
I feel for ya man... about how mine turned out. I know that book has a bad or hard to tell pic of the sprag and which way it goes. Just a thought. Been a year since I had my head in that mode. Also the servos are known to be weak and crack. If ur in there I'd replace all the electric components and those servos. About 150 for the electric s over here.
And remember even guys that do it daily need to do it more than once to get them right. I had mine apart and together atleast 4 5 times before I gave up. By the end I could do it in 20 min. Took it in finally and all it was was the sprag. I have completely tore is down n assembled all those times n was that stupid pic in the book. My condition was super super loose convertor n then it seemed like 2nd was fine. Obviously I'm not a trans tech but I would do it again. Hang in there.
Quickstop [UK]
Combating adversyty.
Re: 4l80e tear down and rebuild
Thanks man, I appreciate the support. :tup:
I put it back together exactly as I took it out so I clearly didn't find the fault the first time. At least I know the pump is good. You're right though, I need to take it apart again. It's also sobering to think that the pros often make simple mistakes so maybe I shouldn't beat myself up too badly. These things are often referred to as black magic and I can see why.
I WILL get to the bottom of it. Testing is the main issue - having to install the damn thing each time is a PITA. :banghead:
I tore it down this time in my dining room - not ideal. Next time I will have more shop space and better tools. I'm going to stockpile a few things in anticipation.
It will not beat me!
Thanks man, I appreciate the support. :tup:
I put it back together exactly as I took it out so I clearly didn't find the fault the first time. At least I know the pump is good. You're right though, I need to take it apart again. It's also sobering to think that the pros often make simple mistakes so maybe I shouldn't beat myself up too badly. These things are often referred to as black magic and I can see why.
I WILL get to the bottom of it. Testing is the main issue - having to install the damn thing each time is a PITA. :banghead:
I tore it down this time in my dining room - not ideal. Next time I will have more shop space and better tools. I'm going to stockpile a few things in anticipation.
It will not beat me!
TYTILIDIE
METH HEAD
Re: 4l80e tear down and rebuild
Mark big thumbs up to you for at least trying to dig in. I am far from a trans guru or know it all but I have learned a hell of a lot and it isn't as scary as some make it out to be once you start to understand the logic in the whole set up.
Moving on, I don't use the PCS controller and I have no experience with it but I do use the factory GM ECM and when the ECM takes a shit it will default to second. You sure that isn't what you're seeing? I cant imagine that if that were the case you would get fourth or even lock up but it is certainly worth looking in to. Are there any fuses on the unit?
When you tear down the trans to that degree, it's always a good idea to inspect ALL of your seals. That one drum is a bitch for sure with the 3 pieces but man you just gotta do it.
Mark big thumbs up to you for at least trying to dig in. I am far from a trans guru or know it all but I have learned a hell of a lot and it isn't as scary as some make it out to be once you start to understand the logic in the whole set up.
Moving on, I don't use the PCS controller and I have no experience with it but I do use the factory GM ECM and when the ECM takes a shit it will default to second. You sure that isn't what you're seeing? I cant imagine that if that were the case you would get fourth or even lock up but it is certainly worth looking in to. Are there any fuses on the unit?
When you tear down the trans to that degree, it's always a good idea to inspect ALL of your seals. That one drum is a bitch for sure with the 3 pieces but man you just gotta do it.
ajt86
Member
Re: 4l80e tear down and rebuild
Did you pull each drum and clutch pack/piston/seal apart? Just popping the drums and clutch housings out is only checking like 10% of the trans
did you follow the flow chart? Its almost impossible to throw a transmission on the table, rip it apart and fix it. If you get lucky and fix it, you may only be fixing the result and not the root cause
Verify what gears you actually have- revving it high to get it moving isnt having a gear. It will most likely want line pressure checks first and then go from there. I have rebuilt hundreds of GM transmissions and rarely see a bad shift solenoid in any GM trans. Get the correct flow chart, and follow it closely and it will lead you right to the issue
Did you pull each drum and clutch pack/piston/seal apart? Just popping the drums and clutch housings out is only checking like 10% of the trans
did you follow the flow chart? Its almost impossible to throw a transmission on the table, rip it apart and fix it. If you get lucky and fix it, you may only be fixing the result and not the root cause
Verify what gears you actually have- revving it high to get it moving isnt having a gear. It will most likely want line pressure checks first and then go from there. I have rebuilt hundreds of GM transmissions and rarely see a bad shift solenoid in any GM trans. Get the correct flow chart, and follow it closely and it will lead you right to the issue
Quickstop [UK]
Combating adversyty.
Re: 4l80e tear down and rebuild
Thanks Mike. Coming from you, someone who does everything themself, that's a really generous compliment. Thanks.
I looked at the electrical harness and didn't see a fuse in there. Both solenoids checked out on the bench with me blowing through them as well as audibly clicking in the trans.
Yeah, gonna just tear it apart again.
Thanks ajt... No, I shied away from taking the clutch packs apart due to a couple of things. I initially thought it was electrical so checked the solenoids. They seem fine. I also read that the fourth clutch is bastard without the tool. I'll get it for next time.
Current plan is to get the line pressures checked out and wire in some bulbs to the solenoids so I can see the shift logic and I'll post up results. Could you point me in the direction of a flow chart I could use?
Thanks - really appreciate your comment.
Thanks Dave, I have a lot to learn on this before I would claim to understand it. One small step for man!
I did put it in D1 and had no 1st gear. To get up to speed, I put it in D2 and got up to 50mph then straight into D4. Foot off gas, TCC applied and I had OD.
In D3 it would shift out of second and just rev. That's why I used D2-D4 to get home.
As I said, solenoids checked out ok on the bench. With the controller disconnected, I had 12v on each solenoid. Grounding them in turn/together made no difference to the speed of the vehicle. I could hear them clicking on and off.
In N, Sol A was energised and I had 0v due to it being grounded and sol B had 12v as the table predicts. I really think the solenoids and logic are ok.
I need to rule out seals at this point. I'll pull it in April. Sucks to have to wait so long to attack it.
So... Transmission pressure tester and 4th clutch seal tool and an overhaul kit are on the list.
Thanks guys - with your help, I'm sure we'll crack it!
Thanks Mike. Coming from you, someone who does everything themself, that's a really generous compliment. Thanks.
I looked at the electrical harness and didn't see a fuse in there. Both solenoids checked out on the bench with me blowing through them as well as audibly clicking in the trans.
Yeah, gonna just tear it apart again.
Thanks ajt... No, I shied away from taking the clutch packs apart due to a couple of things. I initially thought it was electrical so checked the solenoids. They seem fine. I also read that the fourth clutch is bastard without the tool. I'll get it for next time.
Current plan is to get the line pressures checked out and wire in some bulbs to the solenoids so I can see the shift logic and I'll post up results. Could you point me in the direction of a flow chart I could use?
Thanks - really appreciate your comment.
Thanks Dave, I have a lot to learn on this before I would claim to understand it. One small step for man!
I did put it in D1 and had no 1st gear. To get up to speed, I put it in D2 and got up to 50mph then straight into D4. Foot off gas, TCC applied and I had OD.
In D3 it would shift out of second and just rev. That's why I used D2-D4 to get home.
As I said, solenoids checked out ok on the bench. With the controller disconnected, I had 12v on each solenoid. Grounding them in turn/together made no difference to the speed of the vehicle. I could hear them clicking on and off.
In N, Sol A was energised and I had 0v due to it being grounded and sol B had 12v as the table predicts. I really think the solenoids and logic are ok.
I need to rule out seals at this point. I'll pull it in April. Sucks to have to wait so long to attack it.
So... Transmission pressure tester and 4th clutch seal tool and an overhaul kit are on the list.
Thanks guys - with your help, I'm sure we'll crack it!
Quickstop [UK]
Combating adversyty.
Re: 4l80e tear down and rebuild
Zeroing in on my trans issue... I have all gears commanded according to my solenoid chart.
I checked the connector at the trans to see which lines command the solenoids and wired some 12v LEDs to the wires. When the solenoids are grounded, the LEDs light up. I made a little test tool
Line pressure is at the minimum at idle (35 psi in D and 75 psi in R) but I have TCC lockup so I am wondering if there is a pressure regulator valve in the pump that has seized. So I disconnected the controller and got max line pressure. With no controller = max line pressure. 156 in D and About 275 in R. There goes that theory.
Then I put the truck in OD and R and revved the engine against the footbrake and got 100psi and 150 psi respectively.
Despite the solenoids being energised, it stays in 2nd gear until about 60 mph (on stands) and then if I back off, the TCC applies and I can cruise (on axle stands). Solenoids are engaging the TCC at least.
So R is ok
1 commanded, revs in 2nd
2 commanded, 2 works
3 commanded, stays in 2
OD commanded, stays in 2 and revs
If in OD, TCC applies and I can cruise along.
Any ideas?
Zeroing in on my trans issue... I have all gears commanded according to my solenoid chart.
I checked the connector at the trans to see which lines command the solenoids and wired some 12v LEDs to the wires. When the solenoids are grounded, the LEDs light up. I made a little test tool
Line pressure is at the minimum at idle (35 psi in D and 75 psi in R) but I have TCC lockup so I am wondering if there is a pressure regulator valve in the pump that has seized. So I disconnected the controller and got max line pressure. With no controller = max line pressure. 156 in D and About 275 in R. There goes that theory.
Then I put the truck in OD and R and revved the engine against the footbrake and got 100psi and 150 psi respectively.
Despite the solenoids being energised, it stays in 2nd gear until about 60 mph (on stands) and then if I back off, the TCC applies and I can cruise (on axle stands). Solenoids are engaging the TCC at least.
So R is ok
1 commanded, revs in 2nd
2 commanded, 2 works
3 commanded, stays in 2
OD commanded, stays in 2 and revs
If in OD, TCC applies and I can cruise along.
Any ideas?
Quickstop [UK]
Combating adversyty.
Re: 4l80e tear down and rebuild
OK, I have some time to think about this. A few updates...
The trans is out of the truck and sitting...
I haven't had time to work on it seeing as the main focus of this weekend was to send my Syclone away.
I also have another 4l80e...
It was a bit filthy so my Dad and I cleaned it as best we could. I made some space so I have a clear bench for next time I am down.
It's from an HD application so needs the output shaft replaced.
It also has that small pressure relief fitting.
I'm not sure what the 7 means.
Aaaand it's a 97 and up model. I've got the right fitting for the rear oil passage at least.
I have also ordered the Sonnax short shaft to replace this one.
So, the question is now what to do with the two transmissions.
I ordered a new valve body over the summer last year and never got round to checking it. I have also just ordered a new set of solenoids and harness for my early trans. I am going to take it apart, check all the seals and sprags and reassemble it with the new harness and the new valvebody and see where I am at.
If that doesn't work, I need to spend the money for a rebuild kit or perhaps just get a trans builder in the US to make me a decent build.
I am so fed up of learning from all the mistakes I make. I guess I can't be totally self-reliant. I just hope I get a good eventually end up in that situation.
Here are some part numbers if anyone is curious.
The 4th clutch is a bit tricky without the correct tool so I ordered a couple of spare lip seals. The tool is now $200 which is ridiculous. I saw a guy on YouTube do it in 30 seconds without the tool but it is tricky apparently.
inner 24202358
outer 24202357
piston exhaust plug 9427692
Sonnax short shift shaft 38511-01K (There is a -03K as well... guess I'll find out which one I need!)
And the valvebody for Transmission A..
And the solenoid kit...
I might tally up how much this is all costing me to get a running, driving truck, working transmission. Last I checked, I am at $9000 ish.
Wish me luck. :tup:
OK, I have some time to think about this. A few updates...
The trans is out of the truck and sitting...
I haven't had time to work on it seeing as the main focus of this weekend was to send my Syclone away.
I also have another 4l80e...
It was a bit filthy so my Dad and I cleaned it as best we could. I made some space so I have a clear bench for next time I am down.
It's from an HD application so needs the output shaft replaced.
It also has that small pressure relief fitting.
I'm not sure what the 7 means.
Aaaand it's a 97 and up model. I've got the right fitting for the rear oil passage at least.
I have also ordered the Sonnax short shaft to replace this one.
So, the question is now what to do with the two transmissions.
I ordered a new valve body over the summer last year and never got round to checking it. I have also just ordered a new set of solenoids and harness for my early trans. I am going to take it apart, check all the seals and sprags and reassemble it with the new harness and the new valvebody and see where I am at.
If that doesn't work, I need to spend the money for a rebuild kit or perhaps just get a trans builder in the US to make me a decent build.
I am so fed up of learning from all the mistakes I make. I guess I can't be totally self-reliant. I just hope I get a good eventually end up in that situation.
Here are some part numbers if anyone is curious.
The 4th clutch is a bit tricky without the correct tool so I ordered a couple of spare lip seals. The tool is now $200 which is ridiculous. I saw a guy on YouTube do it in 30 seconds without the tool but it is tricky apparently.
inner 24202358
outer 24202357
piston exhaust plug 9427692
Sonnax short shift shaft 38511-01K (There is a -03K as well... guess I'll find out which one I need!)
And the valvebody for Transmission A..
And the solenoid kit...
I might tally up how much this is all costing me to get a running, driving truck, working transmission. Last I checked, I am at $9000 ish.
Wish me luck. :tup:
Quickstop [UK]
Combating adversyty.
Re: 4l80e tear down and rebuild
OK, the verdict is in. The truck is fixed and the trans issue has been solved. You guys are going to laugh. I did. Then I cried a bit.
Essentially, truck was running fine and then it had no drive except 2 and 4. I took this to mean there was an issue with the solenoids and looked into mechanical faults. The controller was sent back to PCS and tested A-OK.
I checked the solenoids by jumping 12v to them from in the truck and listening to them click. All good. It has to be a mechanical issue right?
WRONG.
I put in a junk transmission and it ran but had the same issues. I had no clue. I came back to the electrical idea. I decided that as I had taken the trans apart twice, put a new shaft in and generally dicked with it without really knowing what I was doing, I needed a rebuild. At the very least, I would know that the transmission had been serviced and was working OK.
I got it back about 3 months ago and it has been sitting. I have been so scared to put it in the truck with all the cost in time, anger, frustration. I didn't know what I would do if it didn't work again. MDH came to visit me 2 weeks ago and he motivated me to get it in. We farted around and got it in on the Saturday morning and then it was the same shit.
It ran like crap until WyoSyclone spent about 3 hours tuning. Then we went for a drive. Dammit, same problem. I was so angry and sad and just fed up. This thing is supposed to go like the wind but it just doesn't want to go anywhere.
The next day, we took a closer look at the electrical set up - having had the same issue on two transmissions, it had to be something like that.
So, we decided to see if we could control the trans using switches - it's a binary logic circuit so applying two switches in the correct sequence will give you the 4 gears.
I pulled the harness and started tracing the wires as close as possible to the trans to rule out/ minimise the risks of broken wires and...and... AND.
WHAT THE ABSOLUTE F*CK DID I SEE?
Someone had spliced the A solenoid into the B wire and the B solenoid into the A wire. The logic table was reversed.
Here are the gears:
A B Gear
0 1 1st
0 0 2nd
1 0 3rd
1 1 4th
So 1st and 3rd were swapped (1-0 instead of 0-1) and vice versa which is exactly what I was experiencing driving down the road. This was an easy remedy in the software in the controller but I was furious. I have spent around $3000 on spare transmissions, rebuilds, fluids, valve bodies, tools, shipping....you name it, I fricking wasted time and money on it. I guess the controller took a dump when it lost power at some point and defaulted.
I had issues from day one with this trans and think maybe the original builder did it to fault find. Who knows. The main thing is that I have a working trans and now have a few jobs to get the truck driving. Not long to achieve that sadly so I need to focus. But, it's a huge boost to me.
OK, the verdict is in. The truck is fixed and the trans issue has been solved. You guys are going to laugh. I did. Then I cried a bit.
Essentially, truck was running fine and then it had no drive except 2 and 4. I took this to mean there was an issue with the solenoids and looked into mechanical faults. The controller was sent back to PCS and tested A-OK.
I checked the solenoids by jumping 12v to them from in the truck and listening to them click. All good. It has to be a mechanical issue right?
WRONG.
I put in a junk transmission and it ran but had the same issues. I had no clue. I came back to the electrical idea. I decided that as I had taken the trans apart twice, put a new shaft in and generally dicked with it without really knowing what I was doing, I needed a rebuild. At the very least, I would know that the transmission had been serviced and was working OK.
I got it back about 3 months ago and it has been sitting. I have been so scared to put it in the truck with all the cost in time, anger, frustration. I didn't know what I would do if it didn't work again. MDH came to visit me 2 weeks ago and he motivated me to get it in. We farted around and got it in on the Saturday morning and then it was the same shit.
It ran like crap until WyoSyclone spent about 3 hours tuning. Then we went for a drive. Dammit, same problem. I was so angry and sad and just fed up. This thing is supposed to go like the wind but it just doesn't want to go anywhere.
The next day, we took a closer look at the electrical set up - having had the same issue on two transmissions, it had to be something like that.
So, we decided to see if we could control the trans using switches - it's a binary logic circuit so applying two switches in the correct sequence will give you the 4 gears.
I pulled the harness and started tracing the wires as close as possible to the trans to rule out/ minimise the risks of broken wires and...and... AND.
WHAT THE ABSOLUTE F*CK DID I SEE?
Someone had spliced the A solenoid into the B wire and the B solenoid into the A wire. The logic table was reversed.
Here are the gears:
A B Gear
0 1 1st
0 0 2nd
1 0 3rd
1 1 4th
So 1st and 3rd were swapped (1-0 instead of 0-1) and vice versa which is exactly what I was experiencing driving down the road. This was an easy remedy in the software in the controller but I was furious. I have spent around $3000 on spare transmissions, rebuilds, fluids, valve bodies, tools, shipping....you name it, I fricking wasted time and money on it. I guess the controller took a dump when it lost power at some point and defaulted.
I had issues from day one with this trans and think maybe the original builder did it to fault find. Who knows. The main thing is that I have a working trans and now have a few jobs to get the truck driving. Not long to achieve that sadly so I need to focus. But, it's a huge boost to me.
megapolesc
Member
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