I do not believe it is a tranny problem, but I have to start somewhere.
I have done a few Mods on my wife's 1995 Tbird lately. I recently replaced the 3.08s with a 3.27 tloc. I also updated the 95 intake to a 96/97 style. When I took it out for a test drive all seemed well except downshifting at highway speeds. It seems the car refuses to do a 4-2 downshift. I do not drive her car often and she has no clue what a 4-2 downshift is so I'm not sure when it started.
Since then I have cleaned the valvebody, done a Jmod on the 4R70W I drilled the seperator plate for the mild/gear setting and updated the accumulators, the 1-2 accumlator is using a Blue top spring and no bottom spring, 2-3 accumulator has no springs, I installed a larger OD servo and updated to a 96 trans pan. I torqued the valvebody to 90 in/lbs 3 times. The transmission shifts fine with the exception of 4-2 downshift.
Just as a test I did a manual 4-2 shift, I know it is not recommended. It shifted from 4 to 3 then to 2.
What inputs tell the 4R70W to do a 4-2 downshift?
I figure the engine load is determined by the TPS and MAF and those inputs go to the EEC and the EEC orders the 4-2 downshift.
Any insight would be helpful.
Last edited by Roadhawg; 06-16-2006 at 02:57 PM.