I recently bought a 2000 s80 t6. The car is great. The only problem is if the car is in 4th gear for more than a minute it drops to 3rd and gets stuck in 3rd gear. I was told to swap out the tcm and I was wondering if this is true. Also is there some kind of calibration process for the new TCM? Ive searched everywhere and have found no answers so any help is hihgly appreciated.

 

Failing solenoid holding the overdrive circuit open. You can change TCM's until time itself comes to an end without success.

 

Thanks for saving me from doing that. Is there any way to fix it without dishing out a ton of cash to a volvo mechanic?

 

I have never tried to buy just a solenoid. Who knows if they are available. Getting to this is a job and you might as well replace the transmission with a factory reman unit.

It hurts, but it is the only way to go.