2DMNFST

iTrader: (16)

Hey all, I installed a new MWC 9" with 4.11's into my car last weekend and have a vibration that starts around 40 and gets progressively worse with speed but seems to lessen or stop if the car is in gear, but once you disengage the clutch or put it in neutral it returns.

My pinion angle is currently set at -1.2, and I have had the pst driveshaft re-balanced. Any idea on what to check from here? I have been messing with this thing all week and can't seem to get it figured out.

ramairetransam

iTrader: (18)

does it do it in just 5th and 6th ?

2DMNFST

iTrader: (16)

Nope gear doesn't matter it's strictly speed related.

2DMNFST

iTrader: (16)

Last night I was messing around with it on jack stands and noticed I have a little play in the passenger side axle. I can move it back and forth slightly whereas the drivers side is tight. All backing plate bolts are tight. Not sure if it's normal play or if I have a potential wheel bearing issue.

ramairetransam

iTrader: (18)

call mwc , they will help.

2DMNFST

iTrader: (16)

Put the factory driveshaft in with a conversion u joint and vibration is gone! Not sure what's up with the pst one but at least I can drive the thing again.

SmokedOutZ28

iTrader: (35)

Which pst shaft did you use and do you see a weight on it?

blackandgold

iTrader: (2)

I would see if PST will at least attempt to rebalance it for you. Which shaft were you using?

2DMNFST

iTrader: (16)

Yup it has a weight on it, I also had a local guy look at it and balance it. Not sure if it's a tail shaft bushing issue (factory ds is a tight fit, have to hammer it in and pst is much looser, slides right in) or if the pst has a bad u joint or is too long. It's the 3.5 inch steel pst driveshaft.

MidwestChassis2

iTrader: (1)

You have to be careful over tightening the u-bolt straps that come with your rear end as we have seen a similar issue with vibrations such as this from customers and they had to replace the u-joint and vibrations went away.

Not sure this is the issue but call the shop and we can see what is going on as you have me a little confused by the hammering in part to fit.