350AT shift up/down repeatedly

[72CampSpecial]

ive searched the forums and haven't found a matching issue.. my trani shifts up/down repeatedly under light throttle (around 20 mph/sometimes around 30 mph)..Seems to be more when its cold first 5 min of driving.

Already did a fluid/filter change, swapped out the Accumulator Seal (was leaking) and the vacuum modulator (thought it was bad..but dont think it was after changing it) (and it was a lot smaller than the original??) and installed a new vacuum line from the modulator.

other vacuum lines to look at? Adjustments to make??

it shifts smooth and really good under heavy accelerations..

[luvbowties]

Originally Posted by 72CampSpecial

ive searched the forums and haven't found a matching issue.. my trani shifts up/down repeatedly under light throttle (around 20 mph/sometimes around 30 mph)..Seems to be more when its cold first 5 min of driving.

Already did a fluid/filter change, swapped out the Accumulator Seal (was leaking) and the vacuum modulator (thought it was bad..but dont think it was after changing it) (and it was a lot smaller than the original??) and installed a new vacuum line from the modulator.

other vacuum lines to look at? Adjustments to make??

it shifts smooth and really good under heavy accelerations..

Are you sure you have good vacuum when driving? Got a cam that's robbing your engine vacuum?
Just thinking...
Sam

[Mr Chevorlet]

Check your kick down cable on the side of the transmission to the carb and make sure its not hanging up a little making your transmission want to shift down. Other people call them something else and i am drawing a blank right now.

[buckskins4ever]

Originally Posted by Mr Chevorlet

Check your kick down cable on the side of the transmission to the carb and make sure its not hanging up a little making your transmission want to shift down. Other people call them something else and i am drawing a blank right now.

Your thinking Kickdown Cable AKA Detent Cable

Needs to check vacuum as well. Make sure the Transmission is a dedicated port not joined with others.