904 Accumulator Spring

fishy68 said
I've known John for several yrs. and he is a very knowledgeable trans. man and while he is right it does cushion the application of the clutches and front band (you never said that but it's what gives you 2nd gear so it applies to what we're talking about) he is wrong when he says it is has no affect on any upshifts. I have proved it personally so I know by experience, not just hearsay. And if you or he says I'm wrong answer me this, why did Mopar Perf. for years (going all the way back to when they were Direct Connection) sell a shift improver kit that consisted of nothing but a blocker rod that you installed under the accumulator in place of the spring?

Blocking the accumulator does cause slightly harsher clutch engagement and if your running a stock torque converter I don't usually recommend it. If your running a high stall converter (generally anything over 23-2400 rpm) it cushions the engagement enough that you'd never know the accumulator was blocked.

Would you say that clutch pack clearances on set up may also have an effect on how it shifts? How about parts used like reds vs stock fibers or a 24 Spring return module or kevlar bands etc? The reason I ask is on the one I just rebuilt I used a 24 spring module, reds and I used 5 clutches in the front drum. I set the clearances on the front drum at ,071 and the rear came in at .035 and Kevlar bands. Stall is 38-4200 with a transact RMVB & low band apply. The 2-3 shift is incredible with this set up, 3rd too hit hard enough that yesterday on full acceleration it got a a pretty long roast, I was in shock. Of course this is on the street where traction is limited.