Recently installed 429 with C6 in 59 F100. Trans will not shift into high gear. When engine speed and road speed call for 3rd gear feels like trans goes into neutral, coasts with no engine braking until speed is down to allow shift into 2nd gear. Rebuilt trans, all new seals clutch paks etc. nothing found wrong.
Engine & trans from 71 Contental working when removed. Very little wear on drive train.
Rear diff is 2.73 open,15 in. tires.
Anyone have any ideas?
Thanks
RMM
Not being an automatic transmission expert, I would suggest something got assembled wrong during the rebuild...
Check the roadspeed governor on tailshaft in the tailshaft housing. Should be able to remove only ts housing the get at. You may also want to remove the valve body and make sure you have the correct gaskets and the balls in the correct places. There are several gasket and ball layouts. You need to make sure you are correct for your VB. You can also run the air checks with the VB removed to see if there is any excessive leakage of the clutch packs. If you do not already have an ATSG service manual for it, find one before doing thses checks. They are less than $15US even at NAPA. They may have to order one for you. If you are near a larger city with a trans parts supply house. you can get them there. They are also available online form several sources. If you had a trans shop to do the job recently, contact them before you do anything.
Lugnut
Lugnut
The vacuum modulator has nothing to do with the 2-3 upshift or engagement on the C6. It is controlled by line pressure and road speed gov assuming all else is working as it should.
Lugnut
yea valve body sounds like something to check and the linkage also maybe the vacumm modulator and the vacumm line to it
Can i ask did you have to change out the drive shaft or get it modified?
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