: Loud bang/clunk in reverse



sciroccokid
03-10-13, 10:18 PM
When I place my car into reverse and let the clutch out about 90% of the way I get a very loud single bang noise from the rear. Once rolling in reverse it seems okay.

The car was fine then other day. Then while driving a bit hard I heard a noise from the rear. Drove home slowly. Ever since the bang noise in reverse has happened.

I can drive forward with no noises or issues at low speeds (have not gone over 15mph).

I put in a creative steel diff bushing and block (and v4 rear diff) last year.

Any ideas?

darkman
03-10-13, 10:25 PM
Well if we assume away the differential bushing, which is usually the first suspect, it sounds like something with the driveshaft or rust between the rear hub and the axle splines that other have reported.

http://www.cadillacforums.com/forums/2004-2007-cadillac-cts-v-performance/282296-new-community-any-advice-helps.html

sciroccokid
03-10-13, 10:40 PM
Hmmm... Interesting thread. Thanks for the link. However, this bang is loud (makes you cringe loud...). It doesn't sound like the clicking issue being described here.

I did notice some light rub on the CV of my 1000hp driver's side axle. Looks like new rub. I believe this indicates a shift in the differential. But I could be wrong.

Has anyone seen a creative steel bushing go bad in a year? If so, was it progressive, or did it just "go."

Again, most indicative symptom is that when the clutch is almost all the way released I get this loud bang.

Thanks for the help!

darkman
03-10-13, 10:48 PM
Need clarification - what does "light rub" on the axle mean?

See also:

http://www.cadillacforums.com/forums/2004-2007-cadillac-cts-v-performance/282296-new-community-any-advice-helps.html

sciroccokid
03-10-13, 11:17 PM
In regards to the "rub", its circular scratch on the CV (larger than stock), which appears to come from a nearby bolt. Its minimal, a few scratch rings, which makes me think its associated with the new noise.

I'll try to take a pic this week to clarify.

darkman
03-10-13, 11:28 PM
In regards to the "rub", its circular scratch on the CV (larger than stock), which appears to come from a nearby bolt. Its minimal, a few scratch rings, which makes me think its associated with the new noise.

I'll try to take a pic this week to clarify.

I have the Hendrix 1000hp axles, which I think are similar to the others. They have a set bolts on the inside of each hub that can come loose. They are supposed to torqued to 57 foot pounds. I used red threadlocker on mine and have not problems, but others have has these come loose.

Cadillac Cust Svc
03-11-13, 02:54 PM
Sciroccokid, I do recommend bringing your V to your dealer's attention if the concern persists, in order to have their technicians view the concern firsthand and run the proper diagnostic checks. If you would like assistance working with a dealership at any point, I'm just an email away at Katie_Lucille@gmexpert.com.

Best,

Katie
Cadillac Customer Service

sciroccokid
03-11-13, 04:58 PM
I have the Hendrix 1000hp axles, which I think are similar to the others. They have a set bolts on the inside of each hub that can come loose. They are supposed to torqued to 57 foot pounds. I used red threadlocker on mine and have not problems, but others have has these come loose.

Yes.... This very well may be the problem... I should have thought of that... It addresses each of the symptoms.

I'll check the torque and confirm if that's the issue.

Thanks, you may have just saved me a bunch of time and money.

sciroccokid
03-20-13, 11:03 AM
Resolved.

As it turns out I snapped the bolt holding up the diff on the drivers' side.

This bolt was used to hold up my first diff that was replaced. I advise anyone changing differentials to get new bolts to hold the diff up (carrier bolts?).

Does anyone know the part number for the drivers' side bolt holding the diff up?

NCOGNITO
03-20-13, 10:46 PM
If you're looking for carrier mounting bolts, all 3 bolts are the same # 11519079 --> http://parts.nalleygmc.com/showAssembly.aspx?ukey_assembly=376183&ukey_make=1023&ukey_model=14463&modelYear=2005&ukey_category=19396&ukey_trimLevel=15571

IIRC, you have to drop the cradle to get the bolts through the rear bushings because there isn't enough clearance between the spare tire well and the cradle. The bolts are longer than the what will fit through the bushing. Since your's is snapped off, you *might* be able to get it out, pull the bushing out and reinstall the bolt/bushing as once piece to get it to fit through the cradle.

sciroccokid
04-01-13, 09:50 AM
If you're looking for carrier mounting bolts, all 3 bolts are the same # 11519079 --> http://parts.nalleygmc.com/showAssembly.aspx?ukey_assembly=376183&ukey_make=1023&ukey_model=14463&modelYear=2005&ukey_category=19396&ukey_trimLevel=15571

IIRC, you have to drop the cradle to get the bolts through the rear bushings because there isn't enough clearance between the spare tire well and the cradle. The bolts are longer than the what will fit through the bushing. Since your's is snapped off, you *might* be able to get it out, pull the bushing out and reinstall the bolt/bushing as once piece to get it to fit through the cradle.

Thanks!