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A Learning Hobbist
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Discussion Starter #1 (Edited)
I installed a BM shift kit in my th350 last night. The version I installed was the heavy duty one. Thinking back, I believe it told me to remove the spring under the accumulator cover and just install only the new "O" ring. Did I read that correctly? I just would like to be sure that I did that correctly and don't run into any problems later on.

Thanks,
Steve

1979 Chevy truck
sb350
K10
th350 (B&M shift kit - heavy duty)
 

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Yes you read it correctly, it helps the 1-2 shift. makes it a firm hard shift. My source for this info came from my TURBO HYDRA-MATIC 350 HANDBOOK. The only thing is that if your car is a daily driver you may not want that kind of result.
 

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Did the kit you installed have 2 versions?
- RV/heavy Duty and Street/Strip? (B&M "Shift Improver Kit"?)

If so, as far as I remember, the milder version, (RV/HD), tells you to remove the accumulator spring, and 2 check balls, where the more firm version, (S/S), has you leave the spring in and remove three check balls.

I went with the Street/Strip version (more aggressive) on my Chevelle, and like the shifts it gave me. Very positive, hard tire chirping shifts under hard throttle, and a relatively smooth low-half throttle shifts that won't shake your teeth out in a daily driver.
 

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these kits did indeed suggest removing the springs. THis is the wrong way to firm up shifts........... IMHO.

It is better to reduce flow to the accumilators or add stronger springs.
 

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I think by going with the HD version and removing the spring, it still allows the fluid to run in that same circuit, and still cushions the shift a bit through a restrction somwhere.

But, if going with the more aggressive version, you remove an additional check ball. That redirects fluid through another path anyways (likely one with little or no resistance), so the spring remains in the trans.

I dunno...not sure, I'd have to study a fluid flow diagram to tell you for sure, but I can be sure that mine is set up on the more agressive version, and I like the shifts I get with it.
 

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You don't have to study a fluid flow chart for me. I've worked on trannys for 3 decades.

Leaving the springs out of the accumilator is not the correct method in my opinion. It helps to break the second gear sprag & race with too violent of an apply in second gear.


19_Chevelle_69 said:
I think by going with the HD version and removing the spring, it still allows the fluid to run in that same circuit, and still cushions the shift a bit through a restrction somwhere.

But, if going with the more aggressive version, you remove an additional check ball. That redirects fluid through another path anyways (likely one with little or no resistance), so the spring remains in the trans.

I dunno...not sure, I'd have to study a fluid flow diagram to tell you for sure, but I can be sure that mine is set up on the more agressive version, and I like the shifts I get with it.
 

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You don't have to study a fluid flow chart for me. I've worked on trannys for 3 decades.
Twice as long as me, you'll know them better than I do. :cool:

That's awesome! I do agree with you that removing the spring is not the best way to accomplish the goal they seek.

I've put probably a dozen of these kits in (all s/s versions), and never really looked at a chart to see where the fluid gets re-directed to.

Curiosity had gotten the best of me, I'm gonna look it up when I have time....LOL
 

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A Learning Hobbist
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Discussion Starter #9
Thanks for all of your help. I did put the B&M heavy duty kit in. I use this truck for plowing so I wanted the firmness that it described. Thanks again.

Steve
 
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