HERES THE BEEF .the reasons for this are well known but the fix is not . first of all any kit that jacks up the pressure over 180 psi for a full manual or trans braked 400 is ballooning the convertor from the first time the engine is fired and brought up against the brakes or vehicle weight .160psi to 180psi will work thru 2000 hpower with increased clutch clearances driving up clamping forces at the clutch packs lost by reduced line pressure.with that said ,by reducing line pressure ,blowing off hi convertor charge pressure before it flows thru the input shaft ,charging the convertor before the pr valve upshifts,and bleeding off lube oil at the intermediate shaft (this does not in any way effect durability or reduce oil to the output shaft bushing,or tail bushing and rear seal),we can reduce the tendancy of the convertor from severely reducing or zeroing out the crankshafts front to rear floating and thrusting during normal engine rotation .the rotation of the crankshaft and its associated inertia also tends to pull the flywheel and convertor towards the front of the engine .this also causes crankshaft to ride the bearing harder causing failures .the thing is this when installing a 400 it is a good idea to check crankshaft thrust to verify wear before using the trans ,and periodically to see whats going on .we did a post on pontiacpower1.com about how to check it for those who are interested on the transmission q and a which i host .
