WhiteLightningZ

Well I just installed my Strange 12 bolt rear end, Lingenfelter alum. driveshaft, and BMR adj. TA. Now my problem is when I put 1 or more passengers in the car I get a vibration in the drivetrain that gets worse with the more passengers I carry. When its just me driving I have barely any vibration. According to my angle finder I have 2 degrees of pinion angle. Not sure if its positive or negative. Could my pinion angle be getting thrown off so much by adding passengers in the car that its causing the u joint to bind and vibrate? Any help is appreciated.



-Dan

97FormulaWS-6

First thought says you have the wrong length driveshaft, adding weight drops the car, and puts more of the shaft into the tranny. My guess is the DS is too long and bottoming out inside the tranny.

Did you measure for the new DS or just order it?

WhiteLightningZ

I didn't measure for the driveshaft. I just ordered the Lingenfelter alum. DS. According to Strange I didn't need to alter DS length with their axle which is one of the reasons I ordered it over the Moser.


-Dan

OBE1 95Z28

Proper pinion angle is a "V", with the driveshaft and rear end pinion both pointing down where they meet.

You might also try flipping the driveshaft over and mounting it 180 degrees from it current mounting position.

97FormulaWS-6

We're having a discussion about the Spohn DS in the driveline forum here you maybe interested in.

Basically to sum it up, every car is different, thus the driveshaft lengths for all cars are slightly different. When aftermarket parts are installed things change again; for the time and issues that it can cause, it's easier and only takes a min or so to measure the exact length needed for the DS and not just bolt one on the supossedly works.

I'm running a Strange 12-bolt myself, and had a Denny's NR shaft built... my DS is about 1/2" longer than "normal" for a Strange 12-bolt driveshaft; Denny had me measure it like 2 or 3 times to verify the measurement, so take what MFGs say with a grain of salt when it comes to compadibility.

WhiteLightningZ

I got around to reading the whole discussion about the Spohn DS this morning and wound up measuring my DS. I have exactly an inch of slip yoke clearance before bottoming out on the tailshaft with the car fully loaded with 4 people in it. I even had everybody sit on the back to bottom out the suspension and it still didn't hit. So I went back to checking my pinion angle and realized I had 2 positive degrees of pinion angle with nobody in the car. D'OH! . I wound up setting it for negative 2.5 degrees and poof! no more vibration. So thanks to everyone that gave a suggestion because it made me check just in case. This time it wound up costing me nothing but a few minutes of time and a little embarassment.

-Dan

Joe 97RA

Once I lowered mine, I had the same problem. My solution was -2º pinion angle and airlift bags in the rear springs to keep the suspension from going lower as weight was added. Another degree of pinion angle would have probably done it too.