always faster

iTrader: (6)

Ok when my car was stock , the car wasn t making any noise.

After a couple of month i install a spohn adjustable torque arm that mount to the tunnel brace with a safety loop.My pinion angle is at -1.

Then i ve begin to hear a steady deep sound like :groooooooow........groooooooooooow........grooooo oooow.......grooooooooow.The point(........) are for silence between the noise.I could hear it at around 60mph and over,louder as the speed goes high.And could hear it better in 6th speed.

Since then i stop running the car because over 95mph the sound was too loud so i decide to put some mods and do some tune up, here is the list:

-95 firebird ,6 speed,LT1
-Strange 12 bolts,hd posi,33 splines,3.73 gear,LPW cover
-Spohn chromoly hd drivehaft
-Spohn ajustable torque arm,safety loop
-UMI ajustable lower control arm and panhard rod
-Koni ajustable shock set on stock spring
-Stranos 35mm front sway bar/22mm rear sway bar with poly bushing and end link
-Subframe connector welded
-Strut bar
-UMI C5 brake conversion kit with stop tech braided lines,**** pad
-Magnaflow cat back
-Meziere electrique water pump(43gmp)
-Short stick,160 thermostat,lt4 km, hpp3
-Moroso cai with trick flow elbow
-18"x9.5" all black ZR1,285/35zr18 fk-451 tire.
-Accel extreme 9000 wire with 8 tr55 gapper .050
-Msd blaster coil
-Msd cap and rotor kit
-Power steering pump
-New belt
-ABS/TCS delete ,line lock,proportion valve
-FLUSH and fill of all fluid:rad, power steering,motor oil,transmission,brake
-Alignement and complet grease of the chassis

The car run great,idle perfect,engine temp is fine,shift awesome, the suspension feels great,absolutely no problem.

BUT......

I still got this anoying noise

Do you have any idea of what could it be?
or
Its just that the TA transmit the normal noise louder then the stock unit and i shouldnt be worried

Thank you all for your help

Eric

Sam Strano

iTrader: (41)

Your rear end bearings are getting torn-up..... I'm sure it's the pinion bearings. Most likely due to a bind in the u-joint since it happened when you installed the TA. I'd say your pinion angle is off a fair bit. Or the rear leak oil and killed the bearings, or it was setup all wrong.

always faster

iTrader: (6)

Hmm the noise was there with my stock 10 bolts when i installed the TA, i ve since change it(last week 30miles driven) for the new strange 12 bolts ands still got this annoying deep noise.

So i dont think that my rear end is the problem.

BubaGumpShrimp

iTrader: (1)

recheck your pinion angle and make sure you are doing it right, car must be loaded on all the tires and level ground(drive on lift forks great for this) You can also jack up the car and put blocks of wood(of equal height) under each tire.. After you confirmed that the angle is right check the drive shaft and universal joints... The way you describe the noise and considering that it increases with speed tells me its drive line vibration (had it bad on my elcamino) car would sometimes vibrate but its not a constant vibration more like a pulsing vibration.

always faster

iTrader: (6)

Does an overthighten u-joint strap coud be a cause of this noise.When i connect the u-joint to the rear end with the 2 "strap" i missed some place so i use a key and i thighten the bolts pretty hard.

For the angle precision, i place my car on 4 ramp and check many times and everything seems to be just fine.

I saw this thread:

https://ls1tech.com/forums/suspension-brakes/531597-spohn-torque-arm-install-question.html

He has the same problem as mine except that he successfully fix it.

I ve follow the instruction here:

http://www.streetissuecustoms.com/pinionangle.html

And the noise is still there.The thing that really make me crazy is that i know where the problem is but doens t know how to fix it

Thank you