Is my 4L60E about to crap out?

So my transmission has started doing something... odd.... it started maybe two weeks ago while I was driving back home from work. Doing 70 trans in 4th with torque converter locked ~2200 rpm when bang converter unlocks and rpm jumps up to ~2800-3000....then converter stays unlocked while driving....I got off the freeway and checked and it shifts thru all 4 gears but doesn't lock up the converter. The shifts become harsh when this happens, but it goes away if I pull over, shut the truck off, wait a little bit, restart the truck and get back along my way.

It seems to do it under load (whether a hill or stiff wind) with low throttle input. I pulled codes and P0894 comes up which is a transmission slip code as far as I can tell.

It seems to be getting more frequent...it went from once every few days to now where it did it 3 times in my 70 mile drive to work, albeit driving into this awful gusty wind.

Is this a control logic problem? a torque converter problem? Any of the GM techs know of a problem?

2005 Chevy Colorado 2.8l auto 4x4 just rolled 140k miles


Thanks,

Patrick

Check the fluid level? They can do silly shit when there just a tad low.

PCM is seeing more than 200 rpm slip when in 4th gear TCC locked. Possible causes would be a worn TCC valve bore, hard or split converter oring, worn out torque converter clutch,or a combination of the 3. The PCM goes into limp home mode after code sets causing max line pressure and the harsh shifts. At 140k your about due for an overhaul. A new or repaired valvebody may or may not fix the condition for now.

Wholy shit this is an old post Jesse! Now i respondeded to it think it was recent lol durr.


^^^yup! Sonnax makes some nice kits to repair and or eliminate the tcc pwm function to solve the issue. I'm not 100% sure but I think it cranks the force motor to max pressure anytime it detect a problem and presents a pending code (1st failure) then presents the check engine light on the second failure.


Here is the fix kit from a random vendor but pretains to an 1870 code mostly: http://www.transmissionpartsusa.com/...-07775404k.htm

http://www.sonnax.com/system/instruc...C-4L60E-IN.pdf

P0894 Trans Component Slipping usually is related to the converter lockup is taking longer than it wants to see, usually all related to this valve. The TCC valve is in the Pump body though, not the easiest to get to from the pan area... Pretty much easiest to remove the trans and the pump and fix it on the bench.

Guess it is kinda old,Tom. Whaddya bet he is still driving it this way. LOL

^^ til it warms enough for me to be able to drop the pan/trans in the driveway...you are correct...though the issue hasn't presented itself in almost a month truck is at 144k miles now. Bought the truck knowing the 4l60e was going to be a weak link its only the second auto i've ever owned and the only one that has been driven regularly on road. Anybody know a good rebuilder for these things? was going to go to a larger (and heavier) set of tires but I don't believe the drivetrain is going to like it with the trans in its current state.

Must have been some trash or a burr that went away. I do dable with these auto's. honestly i love working on them, i must be a glutton for punishment!

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Originally Posted by WickedSix

^^ til it warms enough for me to be able to drop the pan/trans in the driveway...you are correct...though the issue hasn't presented itself in almost a month truck is at 144k miles now. Bought the truck knowing the 4l60e was going to be a weak link its only the second auto i've ever owned and the only one that has been driven regularly on road. Anybody know a good rebuilder for these things? was going to go to a larger (and heavier) set of tires but I don't believe the drivetrain is going to like it with the trans in its current state.

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Bring it out we can pull it out on the lift and tear it down