bigfatls6

iTrader: (34)

I just installed a Midwest Chassis TQ arm with the true dual tunnel mount on a 2001 Trans Am. I Also installed an S60 rearend and chromoly driveshaft. The car is a 6 speed and now has a pretty good vibration from about 65 mph up really noticeable at 70. I set the Pinion angle with the drive shaft down 1 degree and with the pinion down 1 degree which should put it right about -2. I set it properly with the weight on the tires. The rear of my car sits at about 28" the front sits about 27". Do you guys think this is an issue with the drive shaft or do I have my pinion angle jacked up some how?

MidwestChassis

iTrader: (5)

Where did you purchase the driveshaft?

Floorman279

iTrader: (11)

try -1 after checking driveshaft. the sweet spot is between -1 and -2......closer to -1 tho is what I've seen on street cars.

bigfatls6

iTrader: (34)

Driveshaft is used and came from a local shop here in Houston. I'm probably fixing to pull it out and possibly take it and have them check the balance on it again.
I also have the TQ arm installed on the lower hole of the two mounting points on the tunnel mount

bigfatls6

iTrader: (34)

bigfatls6

iTrader: (34)

Control arms are in the upper holes on the brackets

bigfatls6

iTrader: (34)

Here's a pic trying to show the angle at the joint

MidwestChassis

iTrader: (5)

My guess is it's the yoke its self is the problem. Measure the outside diameter of the yoke I would be willing to bet that it measures 1.500.

bigfatls6

iTrader: (34)

The Yoke on the drive shaft? Are you talking about where the ujoint goes

MidwestChassis

iTrader: (5)

Yes the slip yoke on the driveshaft.

bigfatls6

iTrader: (34)

Not sure of the measurement your looking for

bigfatls6

iTrader: (34)

bigfatls6

iTrader: (34)

Forgot to mention but it is a 6 speed car

MidwestChassis2

iTrader: (1)

It is your yoke causing the vibration. We have the correct yoke available for the T-56 transmissions.

bigfatls6

iTrader: (34)

What is the issue with the yoke I have?

Launch

He talking about your front yoke that goes into the transmission. The inner splines aren't cut right on some of those forged yokes and they have too much movement on the splines causing vibration.

MidwestChassis

iTrader: (5)

The outside diameter of the yoke is to small I would be willing to bet it measures 1.500 and it should be 1.503 causing your vibration we have seen it numerous times that is why we only use Sonnax yokes on t56 applications.

MidwestChassis2

iTrader: (1)

A couple options for a new driveshaft. Keep in mind we are the only ones that offer this yoke knowing of other issues from multiple different yokes on the market when using a T-56 transmission.

3" Steel

Strange 3" C/M Driveshaft

3.5 Aluminum

Purchase the Yoke separate

bigfatls6

iTrader: (34)

I talked with the guy today that I got the S60 rearend and driveshaft from and I was wrong the shaft is actually a strange chromoly that was purchased with the S60 the local driveshaft shop actually only checked the balance on it due to an issue with loosing a plastic piece located under the cap on one of the ujoints. I also installed my racestar wheels today and it actually got rid of most of the vibration. Weird deal I've never felt a tire balance issue feel like this vibration. Now I just need to get rid of the clunking from the Tq Arm.
What are the Recomendeed TQ specs for the TQ arm bracket to the rear end and the TQ arm attachment at the tunnel mount?

MidwestChassis2

iTrader: (1)

You would torque the bolts that attach the torque arm bracket to the housing back to factory specs and as far as a grade eight 1/2 bolt they have a torque range between 80- and 90.

You have an aftermarket torque arm and a manual transmission, it will react every time you get on and off the gas differently than an automatic will.