Gear Swap Woes - Camaro5 Chevy Camaro Forum / Camaro ZL1, SS and V6 Forums

2010BlackCamaroSS · 10-15-2021, 07:42 PM

I bought 3.91 gears, Truetrac carrier, all new bearings and seals. I took all the new parts to a local shop to install. I told them I want to check preload, backlash, and pattern when they were finished. They were very nice and agreed.

After having my diff and all the new parts for 4 weeks, I sent them an email to check on the status. They replied that it was done and they were getting a good pattern, but that it probably wasn't the "perfect" pattern I wanted. I replied saying "Send me some pics. If it's good, it's good".

After not getting a reply to the email, I drove down there to put my eyes on it. The drive side contact is at the heel and top land, and the coast side contact is at the toe and top land. Since these are face hobbed gears, it seems that there is too much backlash; but the shop said this is the best they could do.

Since I was not satisfied with the pattern, the shop did not charge me for the work and let me take the diff home. Now I'm looking for another shop to adjust the pattern.

Would you guys run the gears with the pattern shown in these pics?

2010BlackCamaroSS · 10-15-2021, 08:00 PM

Also, the shop gouged the crap out of my housing while they had it. It looks like they were using the edges as leverage to pry the internals.

2010BlackCamaroSS · 10-20-2021, 08:52 PM

Any opinions on the pattern shown in the 1st post?

Rick@RKT56 · 10-21-2021, 01:56 PM

It should be more like these.

CamaroCracka · 10-21-2021, 02:17 PM

I would get a new crush sleeve and find another shop. I'm no expert, but it's pretty clear that pattern is pretty far off.

2010BlackCamaroSS · 10-21-2021, 06:18 PM

Quote:

Originally Posted by CamaroCracka

I would get a new crush sleeve and find another shop. I'm no expert, but it's pretty clear that pattern is pretty far off.

That was my thinking as well. Problem is, I don't know where to take it. The shop I took it to talked a good game, but couldn't get it done. I hate to take it to the dealership.

brick59 · 10-21-2021, 06:59 PM

It looks like the pinion depth is off.

brick59 · 10-21-2021, 07:04 PM

Here's what mine looks like.

CamaroCracka · 10-21-2021, 09:03 PM

A lot of shops that do just fine with solid axles don't do so well with IRS diffs. Those crush sleeves take a lot of force. One guy on here suggested starting the crush in a press before you put it together to reduce the initial effort. They really need something like a case spreader bolted to the ground to hold it still while tightening the pinion nut.

The problem you have now is a shop like JRE probably won't touch it because someone else has already been working on it.

oldman14ss · 10-30-2021, 08:06 PM

everyone is right find a shop that knows our diffs. after a supposedly good shop did mine. bad problems!!!!!!!!!!! to get to the point. I had to buy new gears and get someone else to do it. be glad its not back in your car. fwiw I used no shims for the pinion depth. because of modern techniques.

2010BlackCamaroSS · 11-02-2021, 08:41 PM

Quote:

Originally Posted by oldman14ss

everyone is right find a shop that knows our diffs. after a supposedly good shop did mine. bad problems!!!!!!!!!!! to get to the point. I had to buy new gears and get someone else to do it. be glad its not back in your car. fwiw I used no shims for the pinion depth. because of modern techniques.

Only shop I know of locally that knows these cars is the dealership. I'm having trouble on that front as well.

CamaroCracka · 11-03-2021, 08:39 AM

Depending where you are in MS, Gwatney is in Jacksonville, AR.

2010BlackCamaroSS · 12-11-2021, 05:06 PM

Quote:

Originally Posted by CamaroCracka

Depending where you are in MS, Gwatney is in Jacksonville, AR.

Had to drive 2.5 hours to get there, but decided taking it to GPI was the best course of action. Dropped it off yesterday.

CamaroCracka · 12-11-2021, 05:22 PM

I wish they were closer. I would take mine there too.

10-15-2021, 07:42 PM	#1
2010BlackCamaroSS Drives: 2010 Camaro 2SS/RS - L99 Join Date: Jun 2021 Location: MS Posts: 128 View My Garage	Gear Swap Woes I bought 3.91 gears, Truetrac carrier, all new bearings and seals. I took all the new parts to a local shop to install. I told them I want to check preload, backlash, and pattern when they were finished. They were very nice and agreed. After having my diff and all the new parts for 4 weeks, I sent them an email to check on the status. They replied that it was done and they were getting a good pattern, but that it probably wasn't the "perfect" pattern I wanted. I replied saying "Send me some pics. If it's good, it's good". After not getting a reply to the email, I drove down there to put my eyes on it. The drive side contact is at the heel and top land, and the coast side contact is at the toe and top land. Since these are face hobbed gears, it seems that there is too much backlash; but the shop said this is the best they could do. Since I was not satisfied with the pattern, the shop did not charge me for the work and let me take the diff home. Now I'm looking for another shop to adjust the pattern. Would you guys run the gears with the pattern shown in these pics? Attached Images

10-15-2021, 08:00 PM	#2
2010BlackCamaroSS Drives: 2010 Camaro 2SS/RS - L99 Join Date: Jun 2021 Location: MS Posts: 128 View My Garage	Also, the shop gouged the crap out of my housing while they had it. It looks like they were using the edges as leverage to pry the internals. Attached Images

10-21-2021, 01:56 PM	#4
Rick@RKT56 Drives: Corvette Join Date: Jan 2011 Location: Maryland Posts: 135	It should be more like these. __________________

10-21-2021, 02:17 PM	#5
CamaroCracka Drives: 2010 Turbo LS3 Join Date: Dec 2009 Location: Palm Bay, FL Posts: 2,734	I would get a new crush sleeve and find another shop. I'm no expert, but it's pretty clear that pattern is pretty far off. __________________ 2010 SS - On3 kit with downpipe cutout, CTR 78/80, CompCam 239/251 620/632 122+4, E85, Z28 suspension and ZL1 diff with Outlaw axles. Gen6 ZL1/1LE brakes. 2011 Vert - 416/w 230/236 .612/.602 115lsa, 1LE suspension w/32mm rear bar. Z28 diff. ZL1 brakes.

10-21-2021, 06:59 PM	#7
brick59 Sucker Punch Drives: 2013 Black ZL1, 2007 Silverado LTZ Join Date: Jul 2014 Location: N.E. Ohio Posts: 275	It looks like the pinion depth is off. __________________ 427 Dart SHP Pro LS Block, Callies Magnum Crank, Callies Ultra I Beam Rods, Diamond Pistons, AGP twin Turbos 6865, Mast heads, Cam Motion LLR cam, Morel tie bar lifters, Crower roller rockers, NW 103MM TB, ID2600 XDS, Fore Triple, DSX, E85, ARH Turbo Headers, Corsa, Jakes stage 5 4L80, Circle D, RPM Roll Bar, BMR, Carlyle Racing 15" conversion kit.

10-20-2021, 08:52 PM	#3
2010BlackCamaroSS Drives: 2010 Camaro 2SS/RS - L99 Join Date: Jun 2021 Location: MS Posts: 128 View My Garage	Any opinions on the pattern shown in the 1st post?

10-21-2021, 07:04 PM	#8
brick59 Sucker Punch Drives: 2013 Black ZL1, 2007 Silverado LTZ Join Date: Jul 2014 Location: N.E. Ohio Posts: 275	Here's what mine looks like. Attached Images __________________ 427 Dart SHP Pro LS Block, Callies Magnum Crank, Callies Ultra I Beam Rods, Diamond Pistons, AGP twin Turbos 6865, Mast heads, Cam Motion LLR cam, Morel tie bar lifters, Crower roller rockers, NW 103MM TB, ID2600 XDS, Fore Triple, DSX, E85, ARH Turbo Headers, Corsa, Jakes stage 5 4L80, Circle D, RPM Roll Bar, BMR, Carlyle Racing 15" conversion kit.

10-21-2021, 09:03 PM	#9
CamaroCracka Drives: 2010 Turbo LS3 Join Date: Dec 2009 Location: Palm Bay, FL Posts: 2,734	A lot of shops that do just fine with solid axles don't do so well with IRS diffs. Those crush sleeves take a lot of force. One guy on here suggested starting the crush in a press before you put it together to reduce the initial effort. They really need something like a case spreader bolted to the ground to hold it still while tightening the pinion nut. The problem you have now is a shop like JRE probably won't touch it because someone else has already been working on it. __________________ 2010 SS - On3 kit with downpipe cutout, CTR 78/80, CompCam 239/251 620/632 122+4, E85, Z28 suspension and ZL1 diff with Outlaw axles. Gen6 ZL1/1LE brakes. 2011 Vert - 416/w 230/236 .612/.602 115lsa, 1LE suspension w/32mm rear bar. Z28 diff. ZL1 brakes. Last edited by CamaroCracka; 10-23-2021 at 11:57 AM.

10-30-2021, 08:06 PM	#10
oldman14ss Drives: 2014 1ss camaro Join Date: Jul 2017 Location: missouri Posts: 705	everyone is right find a shop that knows our diffs. after a supposedly good shop did mine. bad problems!!!!!!!!!!! to get to the point. I had to buy new gears and get someone else to do it. be glad its not back in your car. fwiw I used no shims for the pinion depth. because of modern techniques.

11-03-2021, 08:39 AM	#12
CamaroCracka Drives: 2010 Turbo LS3 Join Date: Dec 2009 Location: Palm Bay, FL Posts: 2,734	Depending where you are in MS, Gwatney is in Jacksonville, AR. __________________ 2010 SS - On3 kit with downpipe cutout, CTR 78/80, CompCam 239/251 620/632 122+4, E85, Z28 suspension and ZL1 diff with Outlaw axles. Gen6 ZL1/1LE brakes. 2011 Vert - 416/w 230/236 .612/.602 115lsa, 1LE suspension w/32mm rear bar. Z28 diff. ZL1 brakes.

12-11-2021, 05:22 PM	#14
CamaroCracka Drives: 2010 Turbo LS3 Join Date: Dec 2009 Location: Palm Bay, FL Posts: 2,734	I wish they were closer. I would take mine there too. __________________ 2010 SS - On3 kit with downpipe cutout, CTR 78/80, CompCam 239/251 620/632 122+4, E85, Z28 suspension and ZL1 diff with Outlaw axles. Gen6 ZL1/1LE brakes. 2011 Vert - 416/w 230/236 .612/.602 115lsa, 1LE suspension w/32mm rear bar. Z28 diff. ZL1 brakes.