Differential Help - Camaro5 Chevy Camaro Forum / Camaro ZL1, SS and V6 Forums

376LS3 · 03-16-2014, 11:53 PM

So I had a diff built about 3 months ago with a TruTrac and 3.91s. Ever since I put it in, Ive heard and felt a clunk when I shift. I thought it was the GFORCE driveshaft, put the original back in, clunk got better, but still there. Took the guy that built it for a ride, he couldnt feel it, blames the PFADT bushings, yaddy yadda. Over time clunk seemed to get worse, and then out of no where, the back end of the car would move out, and scare the shit out of. Feels like the axles are moving side to side. I talked to a friend that used to build diffs and he said it sounds like my clunk is too much backlash, and the side to side action is a bearing that holds the axles or something. What do you guys think? The first video is my original diff, the second video is the diff thats in the car, and the third video is how much movement the tire has before the input shaft moves. I called the guy that built it, he has called me back.....

Cruz-lo · 03-17-2014, 08:03 PM

Now I cant say if you have a real problem or not but... For what its worth I dont see anything much different than what I have.

As soon as I changed diff bushings the car made all kinds of new noises. Cradle bushings even more. Including the clunking. Been through numerous axle changes (back to stock more than once also), a gear change, new driveshaft parts, engine, clutch etc.. and the noise remains unchanged today.

I am fine with it. Just less dampening from the stiffer bushings imo.

SWAT · 03-17-2014, 08:33 PM

I'm not sure with a TruTrac, but my Detroit Locker has a bunch more movement than stock of the tire to input, like you show in your 3rd vid. That was play in the dif internals themselves & not actual pinion to ring gear backlash....if that makes sense. In my case, that is just how the lockers are & it is nothing to worry about. Like I said though, not sure about the TruTrac.

376LS3 · 03-17-2014, 09:16 PM

Well, I took it over to the guy today and he agreed to open it up on Wednesday. I learned a little more about how TruTracs work and theres a chance everything might be ok. I just wanna be sure since I built this to run at the track, and Im definitely not comfortable at this time running it. The rear end changing directions scares me the most. My take on that is it could be something internally wrong, the tire grabbing a ridge on the road and bushings not "slopping" and taking the car with it, or when the tire grabs a ridge, the TruTrac locks up. Im hoping theres just something wrong because it scares the shit out of me when it does!! Lol!

GFORCE1320 · 03-18-2014, 02:10 PM

Did you have the car aligned after the bushing install? I've seen car that are out of alignment drive pretty crazy especially under acceleration.

376LS3 · 03-18-2014, 07:11 PM

Yes, I had it aligned about 3 days after I did the work. (I did not drive in between) It didnt always do the shimmy after the install. It was fine for about a month after the alignment. Our local Camaro club had a west side meet so us east siders caravanned together over there, so we were doing about 85-90mph. That was the first time it did it, and I was literally expecting to see one of my rear tires roll on by! Lol! The best way to explain how it feels, is it feels like the tire comes undone, makes an "S" shape, then goes back to normal. Hope they dont tell me its "normal."

Synner · 03-18-2014, 07:17 PM

Some ppl have had that happen when a bolt loosened and altered alignment.

376LS3 · 03-18-2014, 07:32 PM

That was my first thought.....toe rod came undone. Everythings tight. Been reading about some TruTracs coming with loose bolts in them. Hoping they'll find something like that tomorrow. If this is the way its going to be now, Ill be ordering a 9".

Synner · 03-18-2014, 08:43 PM

I don't see how a loose bolt in the posi would create a shimmy like that. Bad toe or trailing arm bushing/bolts/alignment I've seen a number of times on here. Maybe cradle bolts are loose or didn't get aligned right on the pins? My trutrac is quiet as can be, I've only heard of a couple factory duds but usually they grenade or sound like a box of bolts.

376LS3 · 03-20-2014, 09:08 PM

Took the car in last night to have the guy that built the diff look at it. He found nothing wrong on the inside except for particles in the oil. Looks like the powdercoat from the axles wore down at the seal. No biggie. The only thing he said he noticed was the passenger side axle has 3/8" play in it, when the driver side is tight. I emailed GFORCE to see if this is normal. Just waiting for a response. All suspension is stock except for PFADT trailing arms, which have been on the car for almost a year. I guess my next plan of action is to remove the PFADT diff bushings and put BMR ones in there. The BMRs are softer, so maybe theyll absorb the driveline clunk and road variances better....

GFORCE1320 · 03-20-2014, 10:52 PM

Quote:

Originally Posted by 376LS3

Took the car in last night to have the guy that built the diff look at it. He found nothing wrong on the inside except for particles in the oil. Looks like the powdercoat from the axles wore down at the seal. No biggie. The only thing he said he noticed was the passenger side axle has 3/8" play in it, when the driver side is tight. I emailed GFORCE to see if this is normal. Just waiting for a response. All suspension is stock except for PFADT trailing arms, which have been on the car for almost a year. I guess my next plan of action is to remove the PFADT diff bushings and put BMR ones in there. The BMRs are softer, so maybe theyll absorb the driveline clunk and road variances better....

Sounds like the inner stub may not be locked in like it should.
I PM'd ya on what to look for.

376LS3 · 03-21-2014, 02:05 AM

Thanks Chris! Ill have an update for you on Sunday.

376LS3 · 03-23-2014, 03:44 PM

Hey Chris,
Here is the movement in the passenger axle. Im not real sure what the guy was talking about, but both axles have the same amount. I undid the axle from the spindle and pulled on it, and it does not come out of the diff. Assuming the retaining clip is doing its job. Does this amount of play look ok?

GFORCE1320 · 03-23-2014, 03:58 PM

Looks pretty normal to me, it might not be axle related or even diff related.

03-16-2014, 11:53 PM	#1
376LS3 Eh, that'll happen Drives: 2010 2SS Join Date: Apr 2012 Location: Mesa, Arizona Posts: 1,841	Differential Help So I had a diff built about 3 months ago with a TruTrac and 3.91s. Ever since I put it in, Ive heard and felt a clunk when I shift. I thought it was the GFORCE driveshaft, put the original back in, clunk got better, but still there. Took the guy that built it for a ride, he couldnt feel it, blames the PFADT bushings, yaddy yadda. Over time clunk seemed to get worse, and then out of no where, the back end of the car would move out, and scare the shit out of. Feels like the axles are moving side to side. I talked to a friend that used to build diffs and he said it sounds like my clunk is too much backlash, and the side to side action is a bearing that holds the axles or something. What do you guys think? The first video is my original diff, the second video is the diff thats in the car, and the third video is how much movement the tire has before the input shaft moves. I called the guy that built it, he has called me back..... __________________ 2010 Camaro SS LS3 - No Modz

03-17-2014, 09:16 PM	#4
376LS3 Eh, that'll happen Drives: 2010 2SS Join Date: Apr 2012 Location: Mesa, Arizona Posts: 1,841	Well, I took it over to the guy today and he agreed to open it up on Wednesday. I learned a little more about how TruTracs work and theres a chance everything might be ok. I just wanna be sure since I built this to run at the track, and Im definitely not comfortable at this time running it. The rear end changing directions scares me the most. My take on that is it could be something internally wrong, the tire grabbing a ridge on the road and bushings not "slopping" and taking the car with it, or when the tire grabs a ridge, the TruTrac locks up. Im hoping theres just something wrong because it scares the shit out of me when it does!! Lol! __________________ 2010 Camaro SS LS3 - No Modz

03-18-2014, 07:11 PM	#6
376LS3 Eh, that'll happen Drives: 2010 2SS Join Date: Apr 2012 Location: Mesa, Arizona Posts: 1,841	Yes, I had it aligned about 3 days after I did the work. (I did not drive in between) It didnt always do the shimmy after the install. It was fine for about a month after the alignment. Our local Camaro club had a west side meet so us east siders caravanned together over there, so we were doing about 85-90mph. That was the first time it did it, and I was literally expecting to see one of my rear tires roll on by! Lol! The best way to explain how it feels, is it feels like the tire comes undone, makes an "S" shape, then goes back to normal. Hope they dont tell me its "normal." __________________ 2010 Camaro SS LS3 - No Modz

03-18-2014, 07:32 PM	#8
376LS3 Eh, that'll happen Drives: 2010 2SS Join Date: Apr 2012 Location: Mesa, Arizona Posts: 1,841	That was my first thought.....toe rod came undone. Everythings tight. Been reading about some TruTracs coming with loose bolts in them. Hoping they'll find something like that tomorrow. If this is the way its going to be now, Ill be ordering a 9". __________________ 2010 Camaro SS LS3 - No Modz

03-20-2014, 09:08 PM	#10
376LS3 Eh, that'll happen Drives: 2010 2SS Join Date: Apr 2012 Location: Mesa, Arizona Posts: 1,841	Took the car in last night to have the guy that built the diff look at it. He found nothing wrong on the inside except for particles in the oil. Looks like the powdercoat from the axles wore down at the seal. No biggie. The only thing he said he noticed was the passenger side axle has 3/8" play in it, when the driver side is tight. I emailed GFORCE to see if this is normal. Just waiting for a response. All suspension is stock except for PFADT trailing arms, which have been on the car for almost a year. I guess my next plan of action is to remove the PFADT diff bushings and put BMR ones in there. The BMRs are softer, so maybe theyll absorb the driveline clunk and road variances better.... __________________ 2010 Camaro SS LS3 - No Modz

03-17-2014, 08:03 PM	#2
Cruz-lo Drives: 2010 2ss RS Join Date: Jun 2009 Location: N KY Posts: 119	Now I cant say if you have a real problem or not but... For what its worth I dont see anything much different than what I have. As soon as I changed diff bushings the car made all kinds of new noises. Cradle bushings even more. Including the clunking. Been through numerous axle changes (back to stock more than once also), a gear change, new driveshaft parts, engine, clutch etc.. and the noise remains unchanged today. I am fine with it. Just less dampening from the stiffer bushings imo.

03-17-2014, 08:33 PM	#3
SWAT Drives: 2011 2SS RS L99 Join Date: Jan 2011 Location: Grand Rapids, MI Posts: 5,708	I'm not sure with a TruTrac, but my Detroit Locker has a bunch more movement than stock of the tire to input, like you show in your 3rd vid. That was play in the dif internals themselves & not actual pinion to ring gear backlash....if that makes sense. In my case, that is just how the lockers are & it is nothing to worry about. Like I said though, not sure about the TruTrac.

03-18-2014, 02:10 PM	#5
GFORCE1320 Drives: 05 GTO Join Date: Jul 2009 Location: Wichita, KS Posts: 1,243	Did you have the car aligned after the bushing install? I've seen car that are out of alignment drive pretty crazy especially under acceleration.

03-18-2014, 07:17 PM	#7
Synner Drives: cars Join Date: May 2011 Location: Oversneeze Posts: 4,544	Some ppl have had that happen when a bolt loosened and altered alignment.

03-18-2014, 08:43 PM	#9
Synner Drives: cars Join Date: May 2011 Location: Oversneeze Posts: 4,544	I don't see how a loose bolt in the posi would create a shimmy like that. Bad toe or trailing arm bushing/bolts/alignment I've seen a number of times on here. Maybe cradle bolts are loose or didn't get aligned right on the pins? My trutrac is quiet as can be, I've only heard of a couple factory duds but usually they grenade or sound like a box of bolts.

03-21-2014, 02:05 AM	#12
376LS3 Eh, that'll happen Drives: 2010 2SS Join Date: Apr 2012 Location: Mesa, Arizona Posts: 1,841	Thanks Chris! Ill have an update for you on Sunday. __________________ 2010 Camaro SS LS3 - No Modz

03-23-2014, 03:44 PM	#13
376LS3 Eh, that'll happen Drives: 2010 2SS Join Date: Apr 2012 Location: Mesa, Arizona Posts: 1,841	Hey Chris, Here is the movement in the passenger axle. Im not real sure what the guy was talking about, but both axles have the same amount. I undid the axle from the spindle and pulled on it, and it does not come out of the diff. Assuming the retaining clip is doing its job. Does this amount of play look ok? __________________ 2010 Camaro SS LS3 - No Modz

03-23-2014, 03:58 PM	#14
GFORCE1320 Drives: 05 GTO Join Date: Jul 2009 Location: Wichita, KS Posts: 1,243	Looks pretty normal to me, it might not be axle related or even diff related.