Arvizu9618

iTrader: (1)

What could cause bad vibration in higher gear on the RR of the car of an open diff.

I have the wheels up in the air and have already replaced the driveshaft with a known good one.

I get some near violent shaking coming from RR of car causing the muffler and dash to vibrate too.

I've recently replaced the rear wheel bearings with axle savers.

Didn't notice anything out of the ordinary with diff when taken apart.

All suggestions are appreciated

RT

Arvizu9618

iTrader: (1)

Sorry for double post

big gear head

Sorry to hear that you used axle savers. Good luck with that. There isin't much inside the rear end to cause a vibration like that. Check the wheel and tire. Might have broken belts in the tire or a broken wheel.

Arvizu9618

iTrader: (1)

Thanks for the reply, I have the rear up on jacks and the wheels off, still getting vibe. Got the front up also, so car is level.

I'm thinking it might be the "Yoke support bushing" (even tho Sofakingdom has never heard of this part) at the rear of the tranny.

big gear head

The bushing is the only thing that supports the rear of the shaft in the transmission. With the yoke removed there is no support, and if the busing is bad then you will loose some of the support. This bushing also lines up the front drive shaft yoke. IF the bushing is bad the yoke can flop around some.

Arvizu9618

iTrader: (1)

Update to vibe problem:

I've replaced DS with an Aluminum one
Installed a new yoke bushing in the Tailshaft of the T5
Re-balanced all wheels

Vibe occurs after shifting into 5th gear and only in the 40-50 mph range while pressing on gas.

Beyond 50 mph, car runs "relatively smooth"

Next step is to replace diff with a posi out of my sons 87 T/A and inspect/replace mounts

Frustrated but living with it...

big gear head

You might just be luging the engine too hard running that slow in 5th gear.

Arvizu9618

iTrader: (1)

Yet another update:
I fixed the problem!
It was a burnt spark plug wire!
The burned wire caused a slight miss that apparently caused erratic vibration at 40-55mph in fifth gear.
I replaced the wire and voila, no more vibration, runs and shifts Smoooooth....
Thanks RT