I was having some trouble with my transmission shifting correctly so I took it to my Indy repairmen to have it fully serviced. (Transmission) Anyway, the shifting does not seem to be any better, I can take it high up into RPM's in each grear and it will somtimes shift but often I have to switch to nuetral then back into drive for it to forward into the higher gear. The guy said I also needed a drive shaft flex disc, is that going to make any difference?

 

The flex disc won't make any difference in your shifting, but here's what can happen if you don't replace one that is cracking: http://www.benzworld.org/forums/r-c1...disc-info.html

 

my 450 will shift fine at 25 mph then at 45 but when I'm running at 60 mph it sounds like it's just screaming... although the rpms are only 3000... it just seems like it is wanting to shift into overdrive... is their a vacuum problem???