Hey guys, I have a 2007 Denali with the 6.2L engine and six speed transmission and Im having some issues. It all stated around may of last year I had the shift track sensor replaced at the dealership. Everything seemed fine but one day my dad was with me and mentioned if it always was a little slow going into reverse, I didn't notice it before having the sensor replaced, so I thought maybe the sensor was just needing to be calibrated, anyways I drove it like normal because it was shifting properly threw every other gear and it was only slow if the transmission was hot. fast forward to July and me and my buddies are about to merge onto the freeway which was up hill so I floor the gas and go well the truck doesn't it red lines and I see the check engine light come on, great. So I let the truck cool off for bit the transmission was at 100 Celsius but the engine was fine, once it cools off we drive up to the hotel and everything seems fine except its really slow going into reverse now. Anyways it was a couple days before the dealership where I was at could get it in, but the truck was driving fine so I just drove it gingerly, I did notice that the tranny was running warm though like 70-80 degrees in town but i just thought it was because it was +35 out. So the dealer ship takes a look and the codes that were thrown were from the pressure silnoid so I thought ok great, why did it go off, well heres the funny part, the dealership, in my home town, where they replaced the shift track sensor, well they over filled the transmission by 4 1/2L. 4 1/2L!!! what the shit, so the dealership where im staying does a transmission flush and put the correct levels in, says its all good. Im driving it but it still seems to be a little slow going into reverse, and sometimes it still redlines if I have it gunned at 110km/h.
Fast forward to now and Im starting to get worried, its still low going into reverse, but only when the transmission has reached around 50 degrees and then I notice it. The delay hasn't got any longer though, and it still does the redline and 110 km/h. So I checked fluid levels and all is good, It doesn't smell burnt and its still a nice pink. But I want to get it checked because its starting to shift funny, less smooth I should say. The truck has 150,000 km on it Im just praying that I don't need to have the transmission rebuilt because its not slipping it just doesn't feel as smooth. Is there a chance that it could just be the pressure silnoid or do I see a new transmission in my future.