Diagnosing an Overheating Condition
For the purposes of this article, we were working on a 2008 GMC Acadia that required internal repair of the transmission. In this specific instance, a reman unit was installed as the replacement. Similar to the diagnosis and repairing of this unit, the R&R is fairly straightforward also. Paying attention to things like cracked flex plates, reprogramming of the TCM, performing Fast Learn and getting the transmission to the correct fluid level are important items to check for a clean installation.
All Plugged Up
In this particular situation, Dave had been working on a 2001 BMW 740i with a 5HP24 transmission. The vehicle originally came in with a complaint of leaking from the front. The unit was very low on fluid, was slipping and the fluid was burnt. The shop recommended that the transmission be overhauled because of the conditions mentioned and the mileage on the unit. Everything went normally with the rebuild, and the customer left with a properly working unit.
Food for Thought: How Hot Is Hot?
How long have you been in the transmission business? Have you ever honestly sat down and thought about how an automatic transmission heats up? I mean, how hot does it get and how fast does it get there? Does the temperature stabilize as it does in an engine, or is it always changing? Have you ever taken a car for a nice long drive to be sure you “got it hot” and not been able to reproduce the problem? I’m sure you always figured that stop-and-go city driving creates more heat than driving on the highway, but how much more?