LS1/T56 1st gen Camaro guys.....I need andvice with a driveshaft issue......

[Kokamo]

Hey guys, I have a 69 Camaro with an LS1 and a T56. I think I am having an angle problem on the driveshaft that is giving me some serious vibes.

Just to let you know what I have changed/done recently.........I have had the motor and trans working in the car for a few weeks turning a stock original 2.73 geared 10 bolt 8.2" rear end. Recently I upgraded to a 2nd gen Camaro 10 bolt 8.5" rear with 4.88 gears and shortend the driveshaft 1" and had it reballanced.

Now at around 50ish MPH I have one bad high frequency vibe. It gets worse the faster I go.

So last night I pulled the wheels and put it on jack stands. Put it in gear and I still get the same vibe. Then I measured driveshaft angle. I come up with the following......I hope you can follow me here.......

I zeroed out my protractor on the driveshaft, the rear yoke going into the rear axle is pointing down at 1.5 degrees....seems ok, but could be better. Then I get a measurement on the front yoke....the one coming out of the trans that is hooked to the driveshaft.....it is at 8 degrees pointing down as well. So it looks kinda like this......\___/.....but not as steep....you get the idea. So basically the driveshaft is hanging between yokes.

My thoughts are that the transmission angle is too steep and needs to be pointing directly at the driveshaft or higher.

So here is my question......does the shifter come up inside the cab of the car? I think if it did, I would have a better output shaft angle and my vibes might go away. Also I might be able to lower the front of the motor a little bit, but not much. Don't know how I'd go upon doing that.

Keep in mind I havent had the shaft re-ballanced just yet, so thats still up in the air.

Also, before you ask, the u-joints are new and it has the clips in the rear joint with absolutly no play, caps are at 17 pounds tightness, axles are not bent, new bearings everywhere, and synthetic oil in the rear if it makes any difference.

I am kinda looking for guys that have had a vibe with the same setup.

Thanks for any help, I would really appreciate it.

Joe

BTW.....I will be getting the shaft re-ballanced tomorrow and I will reply back with results.

[ErikLS2]

In my opinion, while checking the driveshaft balance won't hurt, your problem is your u-joint angles. In a perfect world, the pinion gear/rear yoke should point up the same amount the transmission output shaft points down. Around 3 degrees each max probably, 8 degrees is a lot.

Assuming the driveshaft is balanced, I would raise the transmission as much as you can without hitting the floor pan and test drive it. The vibration should at least be much better, if it's not gone, then you'll have to rotate your differential upwards a bit. I would also check for a tight u-joint, with the driveshaft out of the car, if you feel any "tight" spots in the joint that could cause this too but it's usually a less severe higher frequency vibration.

Erik