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4L85-E Transmission Having Serious Problems.


Full Member
Jul 26, 2002
Has anyone else had this happen on their 2002 2500?
I have the 4.10 rear end; and pull a 7000+ lbs. Sonic Powerboat.

My driveway has a bit of a dip to it, about 15 feet infront of the garage. It drive the AV up to the garage door, and leave it overnight, so the vehicle is pointed nose up by about 15 degrees. When I come out the next day, fire up, and stick it in Reverse, the truck merely rolls down the incline, into the dip, and does not provide power to back up the rest of the driveway for about 20-30 seconds. This is a very intermittant problem. Also, sometimes, the transmission has more problems for the first 30 minutes of driving, by slamming into each one of the gears as it automatically shifts. This is a horrible problem to be having with a brand new truck, purpose built, and purpose bought to haul my boat. I have not had the boat behind the truck during any of these problems, but that is irrelevant. I believe the harmonic balancer and/or the torque converter are having major issues with drainging fluid into the pan overnight, like something may have a crack or a hole in it, and it drains only when that hole ends up on the bottom when I park it for the night. Does this sound feasable? I really need some help here. the Chevy dealer has had the truck twice, both times NTF. The second time, they replaced the Valve Body. It is still having this intermittant problem.
:mad: ??? :6: :7: :8: :9: :C:
That's definitely a problem, and not the fault of the inclined parking. I have an inclined ramp to my garage also, and sometimes park my Av on the incline (with the parking brake set of course). I've never experienced what you are referring to, although my Av is a 1500 5.3 w/ 4L60E.
I'd be camped out at the dealership until they fixed it were I you. Don't accept anything less than total satisfaction. If the dealer won't give it to you, I'm sure GM Customer Satisfaction will be glad to take over for you. ;)
When any car or truck with automatic trans sits the oil form the torque converter drains back into the pan to some point. Normally the oil is pumped back into the torque converter within a few seconds of the engine running. Being on an incline could be draining more oil back to the pan than normal. If the trans filter or filter o-ring were defective this could cause a delay in the pump getting good suction since it might suck air into the pump. This might not even show up on a flat parking space. Air getting into the hydralics could be causing the shifting problems.
I have the 2500 and have never experienced any of the problems you mention. I have parked flat, on hills, one rather steep one for a week straight. I put it in gear, it goes into gear. I would definetly ring your dealer till it gets fixed right!
I just bought a 2006 Z71 with the 5.3L. It has 26k miles on it. I'm having this same issue but only when the engine is cold and ambient temp is below 35F. I am also parking on a 10-15% grade nose up. If it does it again, it's going to the shop. Anyone find a reason as to why this is happening?
Mine is fine and I pull 8100 lbs. worth of trailer. Have you checked the fluid level...flushed  the trans? If not, old fluid may have thickened and be causing your problems.

original posts were from '02, but I had the same problem with my tranny, only about 10000 miles on it at the time, 4 trips to the dealer, and about to go the lemon law route, I left it with them for a week, they left it parked on an angle, got a new tranny out of GM finally, haven't had a problem since.