Recently rebuilt tranny acting funny

x182dan

Registered User
The tranny was rebuilt about 2,000-3,000 miles ago with heavy duty clutches and so on. Now all of a sudden its acting up, first to second shift is always good but 2nd to 3rd shift bucks now if I drive it normal but if its at a higher rpm and I am on the gas it when it shifts to 3rd it doesnt do it. Kinda feels like a standard shift when it bucks. It has jmod and 2500stall in it if that helps.
 
It bucks on 2nd to 3rd shifts only when I'm driving it normal if I am on the gas it won't buck at all.
 
x182dan said:
It bucks on 2nd to 3rd shifts only when I'm driving it normal if I am on the gas it won't buck at all.
Do you have the 2-3 spring out? what about the accumulator for 2-3 did it get updated? what valvebody? the newer valvebodys are missing the pac man plates that hold the 2-3 spring retainer up. They require the later design retainer.
I guess what you are describing as bucking is a shift that is too firm. Personally I like to leave the spring in when using all pre 96 valvebody's I don't know why but that is what works best for me.
 
Its bucking like a manual tranny would do when you first take off with it. Seems like the engine is bogging down. I didnt do the jmod the tranny guy did it I just gave him the instructions on how to do it from tccoa.com
 
Well I don't know what to tell you then. It's hard to troubleshoot a minor transmission problem on a modified transmission that you don't know how it has been modified. 2500 is not a very high stall converter, I guess it is a 12 inch? Most cars bog on the 2-3 with a stock converter and a j-mod trans, a chip will correct that, it is all caused by the timing retarding for the shift.
 
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Do that first,But don't have them crank the pressures up on the chip. I have a chip that was written by an idiot that the pressures are way to high.
Alan
 
I am not sure what the chip was burned for because I bought it used from a stock 1994sc automatic just like mine. It is installed right now but it definetly bangs 3rd a lot harder than 2nd and before the chip it would only shift at 4500 WOT in first to 2nd shift and the chip fixed that
 
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