transmission/torque converter slippage sensor

[IGottaSy]

Ok guys. This is for the tech gurus.

I was just thinking that it could be possible to add a hall effect sensor such as those used for the ABS system to the transmission and compare it to the VSS signal in our trucks to detect slippage. It could be mounted to the rear driveshaft, flywheel, ...??
Of course, it sounds easy just talking about it but could someone please jump in and elaborate on this , Please? IWannaKnow.
I know if the RPM s skyrocket and the speed doesn't keep up, then we have slippage(flaring).
What would be needed to achieve such feat? Thanks in advance gents!!!

Parts list:
1. DRAC
2. Reluctor
3. Sensor

 

[DaveP]

Re: transmission/torque converter slippage sensor

Buy a 1996-up with OBD II. Code P1870 "Transmission Component Slip" is already in there. Does exactly what you are trying to do.

 

[Quickstop [UK]]

Re: transmission/torque converter slippage sensor

Dave's right and it can be earlier than 1996 if you have a standalone controller. My PCS controller on my 91 80e trans can tell slippage - it's how I decided to go a different route with my TC.

You possibly could do it but it would be stupidly expensive and tricky and you'd need expert machining help and everyone will ask you - why don't you just get a 4l60E and use a standard controller with all that functionality? GM already did all the R&D.

If you wanted to measure slippage, you'd need to put a sensor and reluctor on the drums/gears in the trans and compare them with the output VSS like you mentioned. This would mean drilling holes in the case for the sensor, drilling holes in the drums and adding the reluctor assembly, balancing the new weight and clutch etc. as well as then making sure clearances allowed the sensor to pick up the signal.

After that monumental hurdle has been passed, you need to process your signal. How much slip? Any slip? Or do you want a digital signal processor complete with signal analysis... You're into software now...

If you want this option, you'd be insane to try and DIY. GM have thought of it for you. They're nice like that .

 

[IGottaSy]

Re: transmission/torque converter slippage sensor

Alright, Thanks for responding! There is yet another benefit of upgrading to a 4l80e. I was just really wanting to know how that works and what is needed to make happen. I hardly have time to work on the truck much less spend time chasing wild geese.:lol:

 

[Quickstop [UK]]

Re: transmission/torque converter slippage sensor

I know an 80e can do it and would presume that a 4l60e could as well. Best bet is to look at controllers. I'm not sure the outlay for an 80e would be justified by that functionality if you can also get it in a 4l60e. But if you are considering upgrading, yeah, it's a perk.

:tup:

 

[2kwik4u]

Re: transmission/torque converter slippage sensor

Wheel Speed and Engine RPM are already in the data stream right? Dump the data to Excel and compare. Will give you total slip between crank and output shaft. Not real time data, but data none-the-less.

 

[Quickstop [UK]]

Re: transmission/torque converter slippage sensor

Wheel Speed and Engine RPM are already in the data stream right? Dump the data to Excel and compare. Will give you total slip between crank and output shaft. Not real time data, but data none-the-less.

That would only be useful when the TC was locked unless you logged all the driving conditions and then compared them to see how the TC responded at various throttle positions and load.

Lots and lots of data points.

 

[IGottaSy]

Re: transmission/torque converter slippage sensor

No one has mentioned that the gear ratio that the trans is in has to be taken into consideration to calculate the slip present between points before and after the gear train, which all the points used and mentioned for 60e and 80e are.

The 80e TISS reluctor wheel is on the 4th gear drum, so it is representative of the speed after the converter. The 60e uses engine RPM as the input speed, so it uses speed prior to the converter. In both cases, the program has to determine what gear it is in, for the 60e whether the TCC is applied or not, and apply the known gear ratio between the input and output speeds, and then compare the detected speed difference with the expected speed difference.

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P1870 in GM OBD II is a notoriously problematic code in 1996-2002-ish 4L60e. It is set by a worn valve body bore that does not allow the converter to fully lock up. The PCM detects the slippage and sets P1870. One of the side effects of P1870 is that the PCM commands full line pressure to "save itself". Soccer mom has no idea why her Suburban all of a sudden has a VERY hard 1-2 shift, but nothing else seems out of place so she keeps driving it until the sunshell busts (because of the full-line 1-2's), and there's no 2, 4, or Reverse anymore and it goes to the trans shop on a flatbed.

Soccer dude here. I have experienced this on my 270K mile 2000 Silverado 2500 after some hard accelerations. Had full pressure until passage was cleared of obstruction(I think) and went back to "normal". Now it has torque converter shudder but keeps on keeping on. I drive it like a soccer grandma now.