Transmission problems?

I have a 2000 Chevy Malibu with 110,000 miles, 90% highway driving. Radiator is filled with Dexcool. Transmission is fine until stop and go traffic causes coolant temp to rise a little above normal. The transmission then starts to slip at start and then on every shift of gear. What is causing this and how do I repair?

When was the last time you had it serviced??


Haven’t, owners manual recommeds service @ 100,000. Getting ready to do that now, but wanted to make sure that I did whatever else could be causing the problem.

Automatics should be serviced with a pan drop filter change every 25-30k… These transmissions are known for their pressure control solenoids being troublesome. That would have to be checked out by a trans shop. Is the fluid level good??? Check hot, on a level surface with the gear selector in “P”.


Can’t check transmission fluid level, it is a sealed transmission with cap directly under the exhaust manifold.

Ok, then what I would do is let a trans shop check out that EPC solenoid. It controls the line pressure inside the trans.


Just a note: The #1 Transmission guy around is Transman. While no one is 100% right he is close.

I have seen those 100,000 service things. With very few exceptions you will do well to follow exactly what is in the owner’s manual. One of the very few items that IMO should be done different is the transmission service. It is not all that expensive and IMO it should be no later than 50,000 miles and frankly Transman is likely right about sooner. (Note: he did not say flush it. He said: pan drop filter change every 25-30k

Thanks guys, I will do fluid and filter change and let you know if I am still having problems.