Th400 2-3 accumulator mod

[kinrob@xtra.co.]

Hi All, running a TCI superstreetfighter TH400 behind 454BBC TT in road race application. 2-3 shift gets long-ish towards the end of a race once trans fluid temp gets up. At last tear down the direct frictions were looking a bit sad so I tried inverting the 2-3 accumulator piston to quicken the engagement and reduce slippage (it was already installed without the accum spring) - this involved grinding the castles off the piston top and installing it upside down in the VB. It worked - the 2-3 shift was considerably crisper, but seemingly the reduced accum piston height allowed the 2-3 servo piston to fall far enough down its bore for the servo seal to be damaged and I lost manual second engine braking completely. Questions are 1) does the inverted 2-3 accum piston mod have any undesirable side effects (high wear or failure of thrust washers/bearings etc)? and 2) if it is a valid mod how best to remove the delay of the accumulator circuit while still keeping the 2-3 servo piston properly located in it's bore?

Thanks, Andrew Robertson, New Zealand

 

[chris718]

simply plug the hole that feeds the accumulator piston in the valve body

 

[kinrob@xtra.co.]

Thanks Chris, so is this the hole in the bottom of the bore in the VB, or one of the circuits that enters at the VB/case interface? and does this mod kill thrust washers/bearings etc, or hurt anything else? Thanks, Andrew

 

[jakeshoe]

No doesn't hurt anything.
Here:

 

[kinrob@xtra.co.]

thanks for the pic Jake. Cheers, Andrew