xupkid2

I need help brainstorming. I am hearing a loud clunk from the rear of my 951 race car. I recently torn out the trans and motor and when I got it all back together this clunk emerged. I thought my issue was a bad half shaft but have found that is not the issue. The car has a solid trans mount and Lindsey Ultra engine mounts that do not have any issues. The sound is def from the rear of the car and only happens when I hit the gas fairly hard and put some torque on the drivetrain, kind of like making it jerk when you are going slow and hit the throttle hard for a split second. It sounds like it comes from the drivers side but that may only be because Im sitting on that side of the car. Ive checked and it is not gear dependent. Does it in 1st, 2nd and 3rd. The clunk is very loud and solid sounding. Thought it could be the torque tube moving and hitting the tabs on the torsion casing but it is no where near hitting and there are no signs of contact. Ive looked over the entire rear of the car and can not find anything loose or any apparent cause for the clunk.

Here is a link to a video I shot so you can hear when the sound happens. Its at night so you cant see much. My headlights dont work well. Go to 1:30 in the video.

http://www.youtube.com/watch?v=4rTAk...ature=youtu.be

Any ideas what it could be and things I can check. Im out of ideas and am heading to Sebring on Wed.

Thanks
Brian

Dougs951S

Can you get the car on a lift and repeat to see what is making contact? maybe something in the drive line is flexing under torque and making contact that is not immediately obvious or close to making contact when the drive line is at rest. you would be surprised how much stuff moves around when you load it up. This can be done on jackstands too if you are safe and smart about it and use proper precautions.

xupkid2

The issue is that it requires a fairly heavy load to be put on the drive train to get the clunk. I got it up on stands and tried to get it to happen and have not had any luck. Seems I can't get enough load on it there.

User 52121

Damn too bad that axle didn't arrive 2 nights ago, I could've given you a hand! Though I love how you're making quick friends with the neighbors, riding around in the dark with that thing... LOL...

Could it be the exhaust bumping against the body?

Can you maybe have Colleen sit back there and go around again? I've found that the rear hatch area seems to work as a fantastic echo chamber... can be tough to pinpoint the noises coming from behind you. I've had Wesley riding in the back before when I heard a noise, and where he heard it was very different from where I thought I heard it.

xupkid2

Jim, we are on the same page and yes I was pissed that the axle didnt come on Thursday last week cause it would have bene a fun project for you and I haha.

Im headed home for lunch with a guy from work to do exactly what you are suggesting. I also talked to Schuh and he thinks it could maybe be a bad engine mount. I just replaced the mounts with the Lindsey Ultra ones so I may just order up a set of stock ones and have them overnighted in case that is the issue.

User 52121

Cool. Post back or call me when you figure out what it is. Curious.

"I just replaced the mounts".... as in - just now, with this most recent motor rebuild? Have you double checked them to make sure they're tight?

xupkid2

Think I figured it out. Its the other axle and it seems like the clip came off the CV or something and its allowing the axle to shoot out and hit the hub. I got under the car while someone was making it all move and saw it moving multiple inches shooting out to the hub. Ill get it fixed after work and see if that solves the issue. Its always something.