IgorT.455/406

Hi guys.

I have a big problem. I have vibration at speed (70 mph +) that shakes the car and I can no longer stand it. Over the last year, I have changed:

tires, lca, wheels, phr, torque arm, shocks, brakes, even a different rear end, no difference.

Took the driveshaft in, had it balanced, they said it had runout but was otherwise good. Its a 1LE shaft, said Ujoints are good (but I doubt that). I put it back in, still vibes. Put a '82 Camaro V6 T5 driveshaft in, still vibes only worse (when I hit the clutch at speed, vibes get worse). With 4.10s, they come in sooner at about 50 mph. Feel like driveshaft, but I don't know.

I was thinking change the U-joints, get a wheel alignment, and put some rubber inserts between the crossmember and the frame, and between the poly mount and the crossmemeber. I tried the rubber mounts, even 1LE, had 3 different ones in there, all broke. Plus, the vibes were still there only not as bad. Please help. What else could it be, I am going crazy.

vogel18

Check your pinion angle on your rearend especially if you have adjustable LCA's and TA. I have seen where this being out of adjustment can cause some nasty vibrations due to suspension bind from the angle being off. Ideal is 0 degree but I run my Pinion angle at -1 per the recomendations of my spohn TA instructions for daily driven cars and it helped some bad vibrations I had on my car... Good Luck

LPEdave

Is there anyone local to you that would swap driveshafts just for a test drive? Seems like an easy way to help diagnose it.

Dave

Wild1

How does it feel at 70 when you push the clutch in? Does the vibration go away or stay?

IgorT.455/406

Ok. The original driveshaft the car came with when I got it was a 1LE. I had that ds balanced and they told me U-joints were good, but ds had some runout. I tried a ds out of my friends '95 Camaro (steel), and it had vibes. Recently, after I broke the TA (hence why a new one is in there, but from a third gen), I put a ds out of an '82 Camaro with whatever U-joints were in there for comparison, now I can feel the vibes worsen when I push the clutch in at 70 mph. But otherwise, still vibrates. I have new U-joints I am going to put on the 1LE ds tomorrow and try that. But there has been 3 different ds in there, the vibration is still there! I find it hard to belive that ALL the U-joints were bad. But its possible I guess.

Wild1

You sound like you're on the right track... by pressing the clutch your isolating the issue to the rear of the car. I had a vibration and it turned out to be one of the two bolts that are on the torque arm by LG. It is the bar that connects the differential to the trans... One of the nuts was loose about 1 full turn and the vibration is now gone. You may want to snug down those bolts next time your under the car.

Not saying that is the only issue, but it solved my mysterious vibration. Good luck.

IgorT.455/406

I broke the stock torque arm where the bolt goes through it, and cracked it in 2 more places. When I put another torque arm on it, I used grade 8 bolts, with a lock washer and a nylon lock nut, they are snug 100%, I checked the other day. Also, both stock bolts stripped about 1/2 way when the crack happen. I am going to try new U-joints and some rubber inserts seriously, see what that does. After that, I will have to see what to do next.