loreak

I was wondering if its possible if the pinion angle is set way off to cause an escalating vibration as your speed gets faster.

I had a new tailshaft bearing put in because my original walked out on me, and had new u-joints and the driveshaft balanced at the same time. All 4 wheels were freshly balanced as well but when i get on the highway as i get faster the vibration gets louder until its extremely loud into 100+ mph.

The only other things I had done around the time was I installed my torque arm, the bmr tranny mount that relocates the torque arm onto it instead of the tailshaft, and some lca's.

smokeum99ta

iTrader: (15)

Check your pinion angle. -1 to -2 is common to have.

shoemike

iTrader: (25)

if you didn`t have it before your TA install
then it is a safe bet.
BTW did you check the angle after install?

CW00BlackTA

iTrader: (31)

Absolutely! Check that angle. If it's off for too long, it will eat your rear u-joint too.

DAVESS02

iTrader: (30)

Are you still running the 10 bolt?

loreak

Well I drove the car for a while open header after installing it as well as having that tail bearing and driveshaft done so I wasnt sure which was causing the problem.

wrd1972

iTrader: (12)

In my experience with short wheel base Jeeps where bad angles and stubby DS's are concerned concerned, if the angle is off you will get shakes just taking off from a stop then eventually get some vibes. The shaking and vibes comes from the fact that the two u-joints velocities don't cancel each other out like they would if the angles were near equal.

Get an angle finder and fix it, it is rather easy.

BMR Suspension

iTrader: (6)

There is a really good video on our front page describing how to set pinion angle on a torque arm car check it out www.bmrfabrication.com

loreak

so i just went out and checked my readings and heres what I got

Reading from the passenger side with positive being on my dial towards the front and negative towards the rear.

On Driveshaft = -1 degree
On Rear End = +3 degrees

So based on how it seems it needs to be calculated my pinion is +2? or is it +4

The car is not level i have the rear jacked up a little so i can get in there, and im jacking it on the pumpkin so it shouldnt effect the angles.

smokeum99ta

iTrader: (15)

Thats driveline angle. You want pinion angle in relation to the ground. Get your car in the air (with suspenion loaded and car level) and then check the pinion angle.

allmotor

Loreak Its +2 You Need To Adjust It To -2

loreak

so if it is +2 could it cause the vibration I hear or wear out my ujoints like was said earlier.

smokeum99ta

iTrader: (15)

Yes. Adjust your pinion angle down.

loreak

got it adjusted tonight to -2 and what a difference, no hum/vibration at speed anymore and it seems noticably smoother as well. i also figured out what was causing my thump when i dart side to side, my panhard bar relocation bracket was loose and it was pivoting on the middle bolt because the top was loose and has a little play in the hole.

so all in all I am totally happy, now i just need to get the thing inspected.......tsp td's w/ no cats doesnt fly well with the inspectors!

Black02SLPSS

iTrader: (5)

So when you set it to -2 was that just on the rear end? What did your driveshaft angle end up being?