12 bolt gear breaking problems....

Daran Summerton · 08-13-2007, 01:54 PM

I'd go back to.012 and easy out of the water!

Joe Helms · 08-13-2007, 02:35 PM

I used Mark Williams(part #58100) needs minor machining as I remember. I think Moser also makes them. I would spend money on the caps before I spent on the preload covers.

Haywood · 08-13-2007, 02:42 PM

Eric,
For sure on the pro gears. I'm 3100 and a 404 with dot tires and using transbrake i made 20 passes and kaboom with the front wheels in the air. Even had the 12 bolt cover from JA that holds bearing caps in place. Teeth are to brittle and will break sooner then later.

JDEMARZO · 08-13-2007, 04:00 PM

Do not think you can use a street gear with a trans break, to much stress on the teeth, go right to a pro gear and it should not break. You could get by with a street gear if you were just foot braking.

Good luck

John Duzac · 08-14-2007, 03:10 AM

Ericsz: I run a stick shift Camaro with a 12 bolt rear end. I can tell you for sure if my 12 bolt stands up to the loads I put on it, a 12 bold will wokk for you too. 7800 rpm starting line launch and so far no trauble. Pro gear is the way to go!

Don Fardie · 08-14-2007, 08:33 AM

Ericsz,
I know a lot of automatics are running Street gears and the RPM?s you are leaving at should be alright, but Pro Gears will take the most abuse because of the softness at which they are harden to. Setting the BL at .012 is too loose for new and .004 is way too tight for new. Try setting them at ..007 and make sure the pinion depth is set correctly to get the pattern favoring the front of the tooth from center. What type of Gear oil are you running? Red Line makes different Shock rated rear end lubes that have always worked great for me. I run a Stick car with Pro Gears (Richmond) and I had great success in setting my rear ends up this way, after a LONG RUN of breakage in trying to find the right set up.
Good Luck??..Don

ericsz · 08-14-2007, 08:59 AM

Thanks so much guys, I knew I get some real answers from you guys, I keep hearing people say welp its time for a 9 inch. You guys have proven differently which is why I asked you folks...Thanks a lot!

08-13-2007, 01:54 PM	#1
Daran Summerton Senior Member Join Date: Jun 2003 Location: Las Vegas nv Posts: 600 Likes: 18 Liked 66 Times in 37 Posts	Re: 12 bolt gear breaking problems.... I'd go back to.012 and easy out of the water!

08-13-2007, 02:35 PM	#2
Joe Helms Junior Member Join Date: Jun 2007 Posts: 9 Likes: 0 Liked 0 Times in 0 Posts	Re: 12 bolt gear breaking problems.... I used Mark Williams(part #58100) needs minor machining as I remember. I think Moser also makes them. I would spend money on the caps before I spent on the preload covers.

08-13-2007, 02:42 PM	#3
Haywood Junior Member Join Date: Jul 2007 Posts: 21 Likes: 0 Liked 0 Times in 0 Posts	Re: 12 bolt gear breaking problems.... Eric, For sure on the pro gears. I'm 3100 and a 404 with dot tires and using transbrake i made 20 passes and kaboom with the front wheels in the air. Even had the 12 bolt cover from JA that holds bearing caps in place. Teeth are to brittle and will break sooner then later.

08-13-2007, 04:00 PM	#4
JDEMARZO Junior Member Join Date: Mar 2003 Posts: 72 Likes: 0 Liked 0 Times in 0 Posts	Re: 12 bolt gear breaking problems.... Do not think you can use a street gear with a trans break, to much stress on the teeth, go right to a pro gear and it should not break. You could get by with a street gear if you were just foot braking. Good luck

08-14-2007, 08:33 AM	#6
Don Fardie Member Join Date: Feb 2003 Location: Lakeville, Ma Posts: 253 Likes: 0 Liked 0 Times in 0 Posts	Re: 12 bolt gear breaking problems.... Ericsz, I know a lot of automatics are running Street gears and the RPM?s you are leaving at should be alright, but Pro Gears will take the most abuse because of the softness at which they are harden to. Setting the BL at .012 is too loose for new and .004 is way too tight for new. Try setting them at ..007 and make sure the pinion depth is set correctly to get the pattern favoring the front of the tooth from center. What type of Gear oil are you running? Red Line makes different Shock rated rear end lubes that have always worked great for me. I run a Stick car with Pro Gears (Richmond) and I had great success in setting my rear ends up this way, after a LONG RUN of breakage in trying to find the right set up. Good Luck??..Don __________________ Don Fardie 1582 F/S B/G

08-14-2007, 03:10 AM	#5
John Duzac Member Join Date: May 2005 Location: Covington, La Posts: 313 Likes: 63 Liked 83 Times in 20 Posts	Re: 12 bolt gear breaking problems.... Ericsz: I run a stick shift Camaro with a 12 bolt rear end. I can tell you for sure if my 12 bolt stands up to the loads I put on it, a 12 bold will wokk for you too. 7800 rpm starting line launch and so far no trauble. Pro gear is the way to go! __________________ John Duzac D/S 4448 STK

08-14-2007, 08:59 AM	#7
ericsz Member Join Date: Jul 2007 Posts: 140 Likes: 0 Liked 0 Times in 0 Posts	Re: 12 bolt gear breaking problems.... Thanks so much guys, I knew I get some real answers from you guys, I keep hearing people say welp its time for a 9 inch. You guys have proven differently which is why I asked you folks...Thanks a lot!

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