if you guys check out www.rodmillen.com you'll come across a valve body for the GS400 and I was wondering what exactly that does and if anyone had any experience with it if so did it make a diffrence ?

 

Any competent transmission shop can do a valve body adjustment. I think $1,099 for tweaking a few springs and boring (if applicable) the valve body operation is a tad bit expensive. I wonder if Rod Millen does the job in-house.

In theory, the RMM valve body upgrade shifting is pretty hard and responsive... similar to that of the Supra Twin Turbo's 4-speed auto tranny. I suggest you find a local established tranny shop to do a comparison between the specs of a '97 Supra Twin Turbo auto tranny to that of a non turbo tranny and go from there. By the way, the configuration of the 5-speed on the GS is close to that of the non-turbo Supra.