Ran across this TSB for 1999 and 2000 JGC TCM's. From what I read it solves hard shift issues and will effectively change the 4 speed into a 5 speed trany reducing engine RPM's about 400 to 500 RPM's.
Yes, this is true. After this TSB was performed, an extra overdrive gear was created. No idea why they didnt do this from the beginning. Just an other combination of two clutch packs which are pressurized together. The extra overdrive gear reduced the engine rpm with around 500 rpm, reduced the noise and increased the mpg.
I need to find out if this has been done on my 2000 JGC. I think the RPM's are a bit higher than my deceased 02. If it has not, it would boost my MPG's and take some stress off the engine in day to day driving. Thanks very much Frango for your reply.
Normally a placard should be put on the TCM, showing that the TSB was performed. But maybe after so many years its gone.
Whats the rpm at steady cruise at 70 mph?
The stealer should otherwise be able to tell you if the TSB was performed.