4000 rpm / 48re shifting

H

hardint

Cummins Fan
Joined
Apr 19, 2009
Messages
211
How have those of you turning more than stock RPM getting the 48 re to not upshift at 3000 rpm ? I have a TNT R tune but can only utilize :thankyou2: it if I manual shift it, I hope there is a way to alter it,and have it shift at 3800 + when the throttle is at 100 % .
 
get a shift kit with heavier springs for gears, try the different color springs or adjust the throttle valve a little
 
Full manual vb or pcs standalone is the best way to do it
 
I was told a manual VB meant you shift every gear all the time,not to great while towing,The pcs is $1300 but would be a start toward a Allision I suppose.
No one has any luck tuning the valve body for higher rpm ?
The tranny has a shift kit with billet input red/clutches but still not crazy about shift strategy.
Also read of others advancing the throttle valve one tooth but that didn't work well at all.
 
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Correct, full manual with ratchet shifter, you shift ever gear, if your planning big power, you would be going backwards putting in an allison ...
 
Its a waste to shift much higher than 3000 and change in your lower gears...if your putting big power down....the shift is closer to 3400 rpms by the time it does it anyway. Run 3rd out till 3800 and manual click into 4th.
 
Daily driving a manual VB with a gate shifter here....have even towed two cars with it. Not a big deal when you come from shifting a 6 speed.
 
Thanks for the replies,all be it not exactly what I was wanting to hear.My tranny guy lead me to think there was a kit with spring and shims to adjust it but is a PITA to pull the pan multiple times to get the shim package to fit your needs.
Lamiller why do you say the Allision is a step backwards, the GM trucks seem to be doing great in the competion events these days ?
 
Most of the fast duramaxes aren't running allisons

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The allison has a problem with not being able to shift fast enough under big power. Most drag racers who swap a built 47 or 48re for the allison gain .3-.4 tenths.
 
agreed on the allison aspect, our 9.7X 1/4 mile duramax runs a duraflite (47re conversion)

built allusions are sweet for towing, DD and sleds... just not so much drag racing
 
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