I 've posted a few times when i run out of ideas so I thought i'd try it
again. 78 chevy 1/2 ton 4x4, has a vibration at 35 mph when you
brake/accelerate/coast through it. if you brake hard, it does it worse,
doesn't do it as bad with some weight on the back (I.E. trailer or
something), new rear end(did it before) rebuilt transmission (did it before)
new ujoints, driveshaft's tight, still does it. could it be in the transfer
case? it's the fulltime Tcase with the part time kit put in it. I'm
running out of ideas and thought there could be a fitting or bushing in that
old Tcase that could cause a vibration at a particular speed. Anyway,
thanks in advance for your help
That sounds like a driveshaft that is bent, running off-center, or out of
balance. If you had the driveshaft balanced earlier, it is possible that
now, one of the balance-weights has been lost. Another idea: the U-joint
caps may not be driven in equally now (missing any C-clips?), which would
let the driveshaft run off-center. Badly worn splines could also let the
driveshaft run out of true.
That full-time Tcase would make it possible for the front driveshaft to be
the problem, if the front driveshaft is always turning as fast as the rear
Any good driveline shop can check if each driveshaft is running true (not
bent or off-center at the splines or U-joints), and balance it, if
necessary. That is specialized work, but it is not too expensive. Get
some bids, first, to avoid surprises. Run the truck on a frame lift, and
when the speedometer reads 35, any driveshaft problem should be easy to
Replies will bounce, unless you remove
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someone mentioned me have the flexplate checked, so i went back to the guys
who did it and they said it was fine, it did it before and after the rebuild
so I figure they would have caught it. I'm guessing the only thing left it
could be is the driveshaft like red mentioned?
thanks for your help, i think you posted about the flexplate and why i went
back to the guys to have it checked.
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