Vibration After MWC 9" Install

Reply Subscribe

Thread Tools

Search this Thread

Apr 25, 2015 | 10:28 PM

2DMNFST

Thread Starter

Launching!

iTrader: (16)

Joined: Jul 2007

Posts: 247

Likes: 3

From: Glen Arm MD

Vibration After MWC 9" Install

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.

Apr 26, 2015 | 12:32 AM

ramairetransam

TECH Junkie

iTrader: (18)

Joined: Aug 2005

Posts: 3,462

Likes: 75

From: Amsterdam Ny, the good part

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

Apr 26, 2015 | 07:55 AM

2DMNFST

Thread Starter

Launching!

iTrader: (16)

Joined: Jul 2007

Posts: 247

Likes: 3

From: Glen Arm MD

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

Apr 26, 2015 | 08:03 AM

2DMNFST

Thread Starter

Launching!

iTrader: (16)

Joined: Jul 2007

Posts: 247

Likes: 3

From: Glen Arm MD

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.

Apr 26, 2015 | 12:32 PM

ramairetransam

TECH Junkie

iTrader: (18)

Joined: Aug 2005

Posts: 3,462

Likes: 75

From: Amsterdam Ny, the good part

call mwc , they will help.

Apr 26, 2015 | 06:18 PM

2DMNFST

Thread Starter

Launching!

iTrader: (16)

Joined: Jul 2007

Posts: 247

Likes: 3

From: Glen Arm MD

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.

Apr 26, 2015 | 07:32 PM

SmokedOutZ28

11 Second Club

iTrader: (35)

Joined: Dec 2004

Posts: 2,163

Likes: 0

From: NW Chicago burbs

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

Topdon ONE vs. Artidiag 800 BT2: Which is the Diagnostic Tablet For You?

Pouria Savadkouei

Gas Monkey Built a 6-Wheel Ferrari Testarossa With a Corvette LT4 Engine

Verdad Gallardo

7 Most Reliable High-Performance Engines GM Has Ever Built

Verdad Gallardo

Amazing '71 Camaro Restomod Is Modern Muscle Car Under the Skin

Verdad Gallardo

6 Common C5 Corvette Failures and What's Involved In Repairing Them

Pouria Savadkouei

Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph

Verdad Gallardo

Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked

Pouria Savadkouei

Top 10 Most Powerful Chevy Trucks Ever Made!

Hennessey's New Supercharged Silverado ZR2 Has 700 HP

Verdad Gallardo

Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes

Verdad Gallardo

Apr 26, 2015 | 08:36 PM

2DMNFST

Thread Starter

Launching!

iTrader: (16)

Joined: Jul 2007

Posts: 247

Likes: 3

From: Glen Arm MD

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.

Apr 27, 2015 | 08:11 AM

#10

MidwestChassis2

TECH Fanatic

iTrader: (1)

Joined: Jan 2015

Posts: 1,504

Likes: 39

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.