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
P0894 is similar or the replacement code to the p1870
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.