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my tranny wont shift hard even with shift kit

7K views 4 replies 3 participants last post by  notmrgoodwrench 
#1 ·
hello guys i have a 67 chevy s.w.b. truck with a 377 stroker motor in it and a 350 turbo tranny now when i got this truck it already had a posi trac rear end im not sure of the gears in it but it is pretty tall gears anyway i had a guy rebuild my tranny i know the guy does great work he put in a b&m stage 2 shift kit and the tranny will not shift hard at all it shifts just like a normal tranny i took it back to the guy and he told me that the reason it was not shifting hard was my gears they were so tall that it will never shift hard with them now i have had some hot rods with hopped up trannys before and they all shifted hard even with tall gears so can anyone tell me if this guy is right or if he is trying to sock it to me thanks guys and if you need more info let me know
 
#2 ·
what he`s telling you is right. we had a car with tall gears and a shift kit, it wouldn`t bark a gear, we later had another car with a worn out th350 that had a bad shift delay but had 3.73`s in the rear and it would bark`em every shift. the tall gear makes it difficult for it to bark a gear, tall tires make the problem worse, however, i had a th350 with a shift kit, when i first got it, it would bark`em when i wanted it to, after a while it wouldn`t anymore, if there isn `t enough line pressure, it won`t bark them, shift kit or not and the shifts will feel sluggish or just normal. there`s other area`s to look into such as modulator valve, valve body wear, front pump wear, filter dirty and so on.
 
#3 ·
thanks for the reply how much line pressure should you have and let me ask this i heard that you can adjust the modulater valve and make it shift harder too is that true the tranny guy said that he could plug the valve too and make it shift harder but it would only shift at 5000 rpm and i dont want that but if you adjust it arent you doing basically the same thing making it shift at another rpm well anyway thanks again
 
#4 ·
Not... Double is right to an extent. With your gears, it may not be able to "bark" the tires. I would think, if you drove the truck before the shift kit, it would feel like it is shifting harder. You may even feel like it is down on power if it is shifting just a little early. As far as the modulator is concerned, yes you can adjust it. If you turn the screw in, it should shift later and that usually translates to harder.

Good Luck
 
#5 ·
hey guys thanks again i am gonna try to adjust that mod. valve and im gonna make sure that my line isnt cracked or anything too i also thought i would tell you this too when we took this thing on a drive the other day we had it at 60mph in first gear so that rear end has got real tall gears but anyway we were goin 60 and i i was shiftin it manually and when i hit 2nd gear it still didnt shift hard but oh well at least it shifts thats more than it did before so im gonna try these things and if it dont work im gonna deal with it i guess but thanks again guys for all the help
 
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