4l80e tear down and rebuild

[Quickstop [UK]]

I was driving on the motorway on Friday at about 75 mph and the truck started slipping out of OD into 3rd and just revving really high and not going anywhere. If I lowered the throttle, it would upshift to 4th and then I had TCC lockup and was able to continue at 70 and above. Any more throttle and I would downshift and the engine would rev.

When I came to a stop, I had lost 1st gear as well and the engine would pull away in 2nd then upshift to 3rd and just rev. If I manually put it in 2, not OD, I could accelerate to the point where OD would kick in and then I had TCC lockup.

I also have reverse.

So, I have REV, 2nd gear, OD and TCC.

The A and B solenoids are used in 1 and 3 but both need to be on for 4 to work. A is applied in Reverse so it appears my solenoids are good.

I am looking at the manual and trying to workout the fault mode..

If I lost the forward clutch, I wouldn't have any forward gears but I have second AND overdrive so I think that the FWD CLUTCH is good.

I haven't driven the truck far - it has 2k miles on the rebuild.

My theory is this...

My torque converter is lame - it stalls way too high (5000rpm) so I started applying the TCC at low mph to see if I had trans slip or if the TC was actually loose. This was still quite a high RPM so I wonder if the RPM tore loose the clutch and clutch material worked its way into the valve body and blocked some passages for 1st and 3rd gear.

It's odd that it failed within 100 miles of me doing that.

Anyone got any better ideas or ideally an explanation for what I have experienced?

I have to pull the trans anyway for the TC swap so I guess I'll be taking it apart as well.

:tdown:

Has anyone got any ideas? Thanks and FML. :rant:

 

[e95 Ty]

Re: 4l80e failed - no 1st or third

Re: 4l80e failed - no 1st or third

Well, either way your gonna get it fixed now....I wonder if the trans was part of your prob the whole time? Call Chris @ Circle D, have him build you a convertor. You can use my build specs if you'd like (not sure it will be right for you), but I will have to call him as he doesn't usually share custom builds. Our engine builds are pretty close right?

 

[Quickstop [UK]]

Re: 4l80e failed - no 1st or third

Re: 4l80e failed - no 1st or third

Thanks Matt!

I spoke with Chris a lot recently and I think I am going with the 1B Pro converter with a 2500-2700 stall. I need to read up on your build again. If I can get close to your performance I'd be very happy indeed!

Nobody has any ideas?

 

[Quickstop [UK]]

4l80e tear down and rebuild

So I thought I'd share what I have been up to with my trans...

Earlier in the summer of 2013 I suspected that the converter might be a little off (high stall issues). I did a bit of testing and the trans subsequently packed in and left me with only 2nd and weirdly, 4th and TCC lockup. (lost 1st and 3rd)

I had no option but to remove it and investigate what had gone wrong.

I live in London and on a medical student salary ($0), I haven't got the luxury of a lot of spare money. The truck is 300 miles from me but it's a 6hr journey. I am constantly faced with either inaction or expense in order to get anything done. This time though, my Dad decided to help out so the trans got sent to me!

So, the first thing to do was to get the transmission into the house:

It sat there on the kitchen table to the horror of my incredibly tolerant girlfriend and her friends on Facebook, for about a week but yesterday I decided I wanted to tear into it.

As luck would have it, I merely thought I had a gear problem. I though it might be because of clutch material clogging the various valves in the valve body. However, on further examination, I found another, serious problem.

Yup, the output shaft from the trans was twisted!

So my decision to pull the trans was justified regardless of the failure. I had to swap out the output shaft.

The original reason for pulling the trans was the torque converter and the high stall as mentioned above in the other thread.

These markings look stock.

I paid for a billet converter. It looks like I got a rebuild :tdown:. Anyone care to comment?

No debris at least and the fluid looks flawless. 2000 miles max since the trans was installed.

I now plan to buy a Circle D converter. Numerous people have recommended them to me and I have had my eye on one of their converters for about 8 months now. (Pro III Triple disc 258 mm billet lockup). I will order it on Nov 1st this year.

I decided to tear the trans down last night. I don't have much space.

I made the mistake of trying to work on it inside before the fluid had been drained properly

Pan off, pump loose.

Nearly lost a check ball... (there are 8 right?)

Managed to tear it all down and it went pretty smoothly.

This design is a lot easier to work on than the 700R4. It's modular and you can remove entire clutch assemblies. The 700r4 was a lot harder to work on.

The intermediate clutch is the only "loose" clutch and all the material was still there:

I pulled the finall assembly and removed the offensive, deformed, weak, resplined shaft.

In doing so, the rear brake clutch band was exposed:

Yup, it still had the writing on it! Brand new! I'll re-use it.

I have ordered a stock output shaft and as soon as that arrives, I can reassemble the transmission. The pan was clear and there was no material anywhere to be seen. The fluid was also brand new. I am confused as to what may have happened.

Essentially, I had no 1st or 3rd gear (the trans would downshift and the engine would rev in D4 if I pulled away. If I commanded D2, I was able to drive it as I only used 2nd gear.

I had TCC lockup which allowed me to get home at 70 mph (I drove 150 miles like that).

The limp home mode has 2nd gear as a default if the trans fails but no-one mentions 4th gear and TCC lockup. Could it be as simple as the two solenoids failing? I need to check them now the trans is apart.

The only other thing was that the power supply to the PCS controller was from a relay. The relay was hanging from the dash and was sort of loose. It lost connectivity now and again and the controller was fried? As soon as that occurred to me, I tightened it up to prevent that from happening.

The next step is to assemble the transmission with the stock out put shaft. I will be buying a SpeedInc.com input shaft for the transfer case. I know another member (Denny) had a problem with the resplined 80e shaft from George Blake and he too got the SpeedInc shaft later. http://www.syty.net/forums/showpost.php?p=1026688&postcount=55]

More money I don't have!

Anyway, maybe this is interesting or helps someone. I'll add to my saga as it continues.

 

[Quickstop [UK]]

Re: 4l80e tear down and rebuild

And I'll be using the ATSG manual:

I will also inspect the direct clutch and see if it is indeed fried but honestly, I think I have a different issue to clutch failure.

Anyone experienced care to comment please?

 

[Quickstop [UK]]

Re: 4l80e tear down and rebuild

Links fixed - thanks guys!

 

[autoaddictions]

Re: 4l80e tear down and rebuild

Thanks for posting.. I have my Ty at the shop for the meet Minus the engine.. I will pull GB 4L80 next week...Can't wait to see what surprises lay.

 

[Quickstop [UK]]

Re: 4l80e tear down and rebuild

Thanks for posting.. I have my Ty at the shop for the meet Minus the engine.. I will pull GB 4L80 next week...Can't wait to see what surprises lay.

He sold me the rebuild kit which appears to be in the trans (I found Raybestos clutches elsewhere) so it's only the resplined shaft that is weakened. I am of course disappointed but I didn't have any other billet parts.

The trans needed to be taken out anyway and I would have torn it down even if that output shaft hadn't been damaged although thus far it looks like nothing else is wrong which is why I am leaning on electrical fault or a valve body issue.

You might be ok - I do hope so but it seems his rep gets worse as people discover little treats left by him. :tdown:

Glad you liked the post. I'll update as and when I get more parts/info. :tup:

 

[Z SKI]

Re: 4l80e tear down and rebuild

Great post... Looks like you may have a billet TC body..The covers aren't usually billet.. Who made the TC??

 

[Quickstop [UK]]

Re: 4l80e tear down and rebuild

Thanks mate!

I bought it via John Waller - I think it was TCS. If you look in the link in my first post, it shows how many problems I was having with the stall. I had 20% slip at about 4500 rpm so I expected it to stall ( less than 10% slip) at 5k; far, far too high

I originally thought that the TC clutch had failed and blocked some valves. It looks like I was mistaken and high stall was the only major issue.

I'm starting to be optimistic the solenoids are the only issue... :dunno:

 

[bezerk]

Re: 4l80e tear down and rebuild

why havent you ****ed around with the controller? iow take out controller and see if it makes a difference, 2 soleniods failing is being pretty damn unlocky compared to your controller taking a crap...

 

[wildphil]

Re: 4l80e tear down and rebuild

Interesting post. I hope the fix for the trans. issues is not very costly.

I have never overhauled a trans. before. So I will be following this thread.

 

[It's just a six]

Re: 4l80e tear down and rebuild

I think failing solenoids are a common problem with electronically controlled transmissions?
Could be wrong though.

 

[mattw]

Re: 4l80e tear down and rebuild

I like this post a lot and I'm glad you found it relatively easy to tear apart. If mine doesn't work when I put it in this winter or if it fails sometime afterwards I fully intend to tear it down myself and attempt to fix it..

 

[Quickstop [UK]]

Re: 4l80e tear down and rebuild

I got around finally to testing the solenoids today. Just for info,

Sol A Sol B Gear
On Off 1
Off Off 2 (I had 2nd)
Off On 3
On On 4 (I had 4th and TCC worked)

I used a little battery pack from China (£3.50 off ebay shipped - how do they make money?) and got 10 x AA batteries to make a 12v supply. Both solenoids moved freely and sounded fine, clicking merrily away. So that is as I suspected - solenoids are not the cause of the problem. Would that it were that easy...

I thought I had 2nd only and then 4th/TCC. I am beginning to think that either:

1) The loss of power to the force motor caused the line pressure to surge and pop the seals in 1st and 3rd gear or

2) that I lost power, went into 2nd but the engine was revving slower than the gear was turning due to being at 70 mph so it felt like I was in 3rd and not engaging... So the loss of power might have explained it.

But why then was I able to reliably shift from D2 into D4 and get into TCC and 4th?

3) My controller didn't like all the voltage fluctuations and is either fried or needs the flash memory reinstalled somehow.

As mentioned, the valve body was clear of all debris and the fluid looked brand new. I guess I now need to inspect each clutch as I assemble it and air check them to see if any seals are blown or any clutch material has been worn off and eliminate issues from there.

If there is nothing like that then I need to start thinking about having perhaps fried my controller.

I should have a new output shaft in the next couple of days thanks to TNPhoon. :tup:

 

[Quickstop [UK]]

Re: 4l80e tear down and rebuild

More good news.

So back in 2007 when I ordered the output shaft, this was the advice that George Blake gave when asking about putting a 4x4 shaft in the truck: (from this thread: http://www.syty.net/forums/showthread.php?t=53586)

4x4 shaft. No big deal there.
Now. If you have a 1996 or OLDER (lube line ports right next to each other), you MUST have an output shaft that HAS 2 LUBE holes in it. I should probably put up some pics.
If you have a 1997 or NEWER trans you want an output shaft with NO lube holes in it. The 1997 or newer trans has the lube ports approx 10" apart.
That's issue one.

My trans is a 96. The tranny lines are close together. So the output shaft should have had 2 oil holes.

Here is the one I got today. 2 oil holes.

Here is the old one from Blake. No oil holes.

When we spoke, he was asking me about the year of the trans. I honestly can't remember what we said. Conversations were via PM and we all know how good he was at returning calls etc. I can't in all fairness accuse him of "shafting" me but I would have to assume that he asked me specifically about the year of the trans and sent me the shaft on that basis. I am no trans expert so he must have known what I had and must have asked right?

That's irrelevant now albeit annoying - what happens next? What else do I need to check on this build? Fluid was clean, there was no material anywhere apart from one little flake inside that part of the shaft. That caught me by surprise. I'm going to search for the effects of installing the wrong shaft. If anyone knows of any other forums with this info, please point me that way.

One day, this POS will run. :roll:

 

[bezerk]

Re: 4l80e tear down and rebuild

where does that oil lead to? if it builds up on the low pressure side it will not be able to catch the clutches

 

[Quickstop [UK]]

Re: 4l80e tear down and rebuild

More good news...

This is a pic from a 4WD 80e (from PerformanceTrucks.net)

Here is my trans:

Anyone see the difference?

The trans was a 2WD initially. The little freeze plug to the right of the shaft in the picture has an orifice hole for lubrication in a 2WD application but should be closed in a 4WD application.

One more little hurdle...

 

[fivetodrive]

Re: 4l80e tear down and rebuild

how do you plug the hole? New plug?

 

[Quickstop [UK]]

Re: 4l80e tear down and rebuild

also if swaping in a 2x4 style tranny. you need to change the oil feed plug at the 3oclock position. 4x4 is solid plug. and 2x4 is pin holed to flow small oil to slip bearing. gm tech told me it will drop pressure on that line and burn up tranny.

GM part#9427692 and less than 5 bucks apparently. Found one on eBay for $14 inc shipping.