Rear End Clunk - Driveline

[Rawyzf]

Video of Driveshaft movement, LMK if you think this is an issue:

http://www.youtube.com/watch?v=b4BqcveV_Ds

[Rawyzf]

While I was under, I also tried twisting the front of the driveshaft by the Tranny. That side didn't seem to make as much noise. There was only a very tiny amount of play up there, compared to the rear it seemed.

[Rawyzf]

One more thing

While looking at the Diff I noticed that the Pass side bushing had a little gap, I am wondering if I can tighten that up some?

Driver Side, No gap:



Pass Side, Gap:

[spartan466]

Subscribed. I noticed the same clunk after I put in my gForce axles and thought it was the new CV joints in the axles, but when I went under there to check, I have the exact same slop in the driveshaft/diff as in your video. So, not sure if it's normal slop or if I'm starting down the slow path of killing my diff.

[Rawyzf]

Charlie told me that some play is ok, so I am not sure if that is what is causing my clunking.

I'm hoping others who have had this issue will post what the found for a cure.

[Eidolon]

There's always a little bit of play in the shaft through the gears in the diff. But various mods either increase it or make it more apparent.

New bushings in the rear end will make the clunk more noticeable because they transmit it to the chassis. Rawzyf, it looks like you're running the BMR Street bushings, so that'll give you some noticeable transmission of additional diff noise. You may also notice a slight whine on the highway even though your diff fluid is topped up.

I also wouldn't worry about that gap between the bushing "flange" and diff unless the bolt through the diff is loose. The gap between the bushing flange and the diff body will be there because the bushings are internally mated to one another and that half couldn't be pressed in any further.

If you're running GForce axles, the CV joints do have ever so slightly more play. You can evince this by putting the rear up, leaving the car in gear (or in Park to lock the shaft) with the parking brake off, and rotating a wheel by hand. The shaft shouldn't be allowed to move by the transmission, but that lone wheel will still wiggle back and forth. In my car, this does result in a very noticeable low speed clunk when switching from forward to reverse and back. It's been there and more noticeable since the day I installed both the differential bushings and the GForce shafts, but 12,000 miles later, it's still good to go.

[jscruick]

check diff. fluid; a drain and refill with carbon diff. fluid cured my noise problem!

[Eidolon]

check diff. fluid; a drain and refill with carbon diff. fluid cured my noise problem!

That is something to try, and it's not too spendy. GM dealers stock the stuff, and it's about $35 per liter, I want to say. You'll need two. I want to say the diff takes... 1.4 quarts? If the fluid's never been changed, it can't hurt, either.

[spartan466]

There's always a little bit of play in the shaft through the gears in the diff. But various mods either increase it or make it more apparent.

New bushings in the rear end will make the clunk more noticeable because they transmit it to the chassis. Rawzyf, it looks like you're running the BMR Street bushings, so that'll give you some noticeable transmission of additional diff noise. You may also notice a slight whine on the highway even though your diff fluid is topped up.

I also wouldn't worry about that gap between the bushing "flange" and diff unless the bolt through the diff is loose. The gap between the bushing flange and the diff body will be there because the bushings are internally mated to one another and that half couldn't be pressed in any further.

If you're running GForce axles, the CV joints do have ever so slightly more play. You can evince this by putting the rear up, leaving the car in gear (or in Park to lock the shaft) with the parking brake off, and rotating a wheel by hand. The shaft shouldn't be allowed to move by the transmission, but that lone wheel will still wiggle back and forth. In my car, this does result in a very noticeable low speed clunk when switching from forward to reverse and back. It's been there and more noticeable since the day I installed both the differential bushings and the GForce shafts, but 12,000 miles later, it's still good to go.

Thanks... I've read that other people notice a little bump with the gForce axles. I'm not panicking about it right now as everything is still pretty solid in the driveline and even on DRs, I haven't noticed any issues. With all the extra power I have since the Maggie, I'm actually VERY cautious about taking up driveline slack before doing a burnout or launch though... especially now that I see what kind of slop there is in the driveline. The last thing I need is for all that torque to get a running start at my drivetrain!

[thebeast]

I have the same sound. Hasn't caused any issues, but is very noticeable