Drivetrain shudder?

[Nessumsar]

Getting relatively bad drive train shudder at 70mph and 3500rpm. The shudder "pulses" about twice a second. It seems to do it worse on deceleration too. I do have solid engine mounts and a poly tranny mount.

[astroracer]

The solid mounts will definetly transmit more vibration. The 1st thing I would check for yours would be the u-joints. It sounds like one or both may be dry. If they are not greasable they should be replaced.
Mark

[Nessumsar]

I replaced both u-joints when I got the car running; the first time I put the car in gear, the rear joint exploded, sitting in my driveway!

But the shudder is enough to make the change in my center console rattle.

[Chad-1stGen]

Does it shudder at cruise or only under acceleration/deceleration?

[Nessumsar]

It shudders more so on decel, and less on cruise and accel.

[mikes69z]

Is your driveshaft balanced?

[Josh]

I had a similar problem and I went through everything from new mounts to pinion angle changes. The driveshaft was balanced a few years before when I changed rear ends so I never did that. I finnaly had it done when I was on power tour in Indiana because it was unbearable, and that did the job!

[Nessumsar]

Awesome, I will look into getting it balanced.

[CarlC]

Balance and pinion angle.

[Josh]

Be sure to get back to us on the solution..

[Vegas69]

Have been doing a lot of research on pinion and driveline angles. Decel vibration is a sign of a pinion angle problem. I think it's to little. Driveline and pinion angle should be equal but opposite. Meaning the driveline points down 3 degrees...the rearend points up 3 degrees. The driveshaft must also be at the right angle. Classic chevy 5 speed has a good article on it along with googl.e If you just replaced U Joints and they are bad already, there is a good chance you have to little angle as well.

[Nessumsar]

I also just had the Hotchkis leafs put on, the car only has 2800 miles, and the shudder hasn't always been there. Only like the past 2 months.

[Vegas69]

Let me guess....you lowered the car?

[Nessumsar]

Yeah, the 1.5" the leafs gave me, but the car doesn't appear to sit much lower. I will check the pinion angle this weekend, and the drive shaft.