adrynalinjunkie

iTrader: (4)

I bought a great 01' Z28 with enough mods that we just made 416 rwhp on the dyno last week, however my tuner noticed what I have been trying to pretend isn't there, a VIBRATION at high speed in the rear end.

I had the tires checked for balance and they are fine.

I bought the car with a moser 12 Bolt with Richmond 4.11's and a Detroit locker.

The car only has 37,000 on the clock, but it has been LEAKING from the pinion seal ever since I bought it a few month's ago.

To cure the leak I pulled the moser 12 bolt apart and replaced the pinion bearings and races as well as the oil seal. I spun the 33 spline axles on the lathe and checked them for runout with a dial indicator.

I even had the driveshaft balanced and ovcoarse inspected the sealing surface on the pinion yoke.

All of this had no effect on curing the pinion leak.

Should I buy new gears and replace all the bearings? I HATE just throwing parts at something, but I don't know what else it could be.

getusumws6

iTrader: (9)

check your pinion angle, 90% of vibration problems are pinion angle is off.

stburgpete

I have a 10 bolt still but a couple of things came into play with my vib. Harmonic balancer was shot. Replaced it, but vib. messed up pinion yoke and put wear. Put a speedi sleeve on and had to replace axel bearings. I have no vib. and no leaks now.

01ssreda4

iTrader: (96)

What about checking the O.D. of the piece that rides in the seal....

stburgpete

You mean outter demention? If so it will be fine. The speedi sleeves are stronger than the yoke materal and it will slip right in. I had no problem at all.

adrynalinjunkie

iTrader: (4)

Ok guys this thing is still vibrating in the rear at anything over 40 mph.
How do you tell if the balancer is bad?

I am tempted to drain the fluid and put some marking compound on the gears and pull a pattern.

I did take off the broken crappy aftermarket torque arm and mount a awesome new UMI tunnel mount one that totally cured my awful wheel hop problems.

It is great fun to break traction and have the rear end just posi slide a little at speed with no damn wheel hop.

I also bought a good digital angle finder and set the pinion angle with the new adjustable torque arm, but unfortunately this did not help with this damn vibration on the freeway, it is like I am getting a back massage but I am sick of it!!!

Steve Gunn

Sounds like you've done everything, but I'll throw some far-fetched **** out there. Are the wheels seating flush on the hubs? U-joints Ok? Have you spun up the motor and trans without the driveshaft? Have you spun everything up without the wheels? Did your driveshaft toss a weight after it was balanced? Good luck.

01ssreda4

iTrader: (96)

Sounds like a driveshaft issue.

CW00BlackTA

iTrader: (31)

What did you set your pinion angle at and how did you do it? With tunnel mounted TAs you sometimes have to find the angle for your car and if it's a half degree off there will be vibration. Try setting between zero and -1, that's what worked for me. Also, might check the runout of the pinion yoke and the seal surface for nicks and dings.

BruceBufferTA

iTrader: (1)

Try having your driveshaft balanced

Supers

I would balance the shaft, see your local driveline shop tell them exactly what it's doing.