chief455

iTrader: (21)

I just installed a TCI flexplate, Yank PT4000 restalled converter, Strange 12 bolt rear and a Spohn torque arm. I had to put the tq arm crossmember ON TOP of the SLP sfc because the xmember tubes were not cut enough to clear - instructions say to put xmemer to car, sfcs on top of xmember. I tapped the holes and used bigger/longer mounting bolts. Looks sturdy.
With the stock driveshaft and pinion angle at -1, the car was an instant rattle trap! Driving easy for the break in, I eased up the mph, trans shifted fine. The converter feels fine. The whole car is shaking as the mph gets 15-30. I finally get moving and on acceleration the car is vibrating constantly.. I get to 50 mph and pop it in nuetral. The vibrating stays. Rev the motor up and down and the car feels the same. Come coasting to a stop and it's growling down to 0 mph. Put in D, take off, shaking up to 30 mph, smooths out some as I get up to 70 mph, let of and it's "blap-blap-blap" on decel. touch the gas- goes away, let off, clunkity,clunk, blap, blap blap.
Figure pinion angle is off.
Read a zilion ways to set it just to confirm we set it right. Order a Spohn driveshaft and poly mount for the tq arm. Put the new driveshaft in, the rear pinion seal is dripping gear oil 50 miles. Set the angle at 0. Go back out and the car is exactly the same. Tonight while driving I tested things. I put in nuetral while the car was vibrating on accel - kept vibrating but since applied motor torque was released, it changed some. I had what sounds like gear whine at 60 mph and put the car from 4 to 3 - the whine stayed the same pitch relative to mph - not rpm. I coasted from 60 mph all the way to 0 and it was different but still vibrating, and clunky right to a stop. I hear so much noise I can't tell where it's starting!
What would you suspect/change?
1.)The torque arm is not right/violant compared to what I'm used to?
2.)The rear end is junk?
3.)The converter/flexplate?

WJ SOM SS

iTrader: (11)

Wow, chief. You changed so many things at once, that it's going to be a tough find.....My first guess would be a bad flex plate. Also, do a string measure on both sides (center-to-center, front-to-back of wheels) with a friend. That will tell you whether or not the rear is cocked to a angle....Not sure what those aftermarket torque arms will do, or the problems they can cause... WJ

WJ SOM SS

iTrader: (11)

You know, the more I think about it, I think my first step would be to remove that Denny's driveshaft and have it checked for correct balance....That's also a easy start, without having to rip everything apart....WJ

badaSS346

iTrader: (4)

I am having the same problem, where do i go to have the balanced checked?

chief455

iTrader: (21)

I would agree - but it was the same with the stock d/s AND the new Spohn. No change in vibration. I'm leaning toward rearend not centered/torque arm difficult to dial in and more noise with it even when set correctly.
I'm going to put the old BMR tq arm in Wednesday morning and set the pinion angle just as we did before with no issues.

98boxer

iTrader: (7)

Since the rearend is suspect then the panhard rod and lower control arms should be looked at since they help align the rearend, just a thought. Also lift the rear 'carpet' -not the car- enough to see that the rear shock bushing is seated correctly. I had the right side shock bushing not seat correctly through the hole and it caused problems for me, just something to also look at,good luck.

chief455

iTrader: (21)

Slowhawk, WJSOMSS, 98boxer and PurEvl - you were all right.
1. The rear was not centered left to right. We had checked simulated level on the lift - but after driving and on the ground we moved the rear 3/4" to the right with the panhard rod. Major vibes and rattles gone!
2. Slowhawk - took your advice and did the angle again, just went to where it looked best and the car was really smooth now. Still noisy for me - making the rear seem bad so we put the BMR tq arm back in - PERFECT!! -1.5 degrees pinion angle, no more gear noise than my 10 olt and ZERO rattles, vibes or clunks See you at LVD!!! THANKS FOR THE HELP

WJ SOM SS

iTrader: (11)

Cool....Now you'll probably whip my ***.....WJ Best wishes.