At 70 mph and about 2000 rpm, I have noticed that when i lightly press on the accelerator, the rpm will rise but speed will not increase. i press a little harder and the rpm will come back down to about 2000 rpm. Transmission fluid and filter were recently changed so levels are good, but there was no change in behavior. Mechanic did mention that the fluid smelled a bit burnt. This is a rebuilt transmission.
Any ideas what could be happening? I suspect the transmission is going out again.
I think I'd agree with you about the longevity of the current transmission. It sounds like it's slipping. A transmission shop might diagnose a bad solenoid or something which could be allowing the transmission to slip.
Unfortunately, your Yukon came with the 4L60e transmission, which is a weak tranny for what it is required to do. It really is the weak spot in the drive train. The transfer case can stand up to serious hp/tq. I have no clue why GM put such an anemic tranny in their full size trucks. You may consider having your transmission rebuilt with better parts (like the Monster in a Box kit).
The vehicle has slow acceleration issue, when you press on the gas pedal the RPM's rise but acceleration is very poor.
The problem was a small crack in the pipe which connected from air filter to machine and this makes air leak. change the pipe and now big difference in acceleration. So, before changing any part first check all air pipes.
I got this solution after changed many pieces such as air filter and oil filter .... but It did not make any difference.
