12 bolt gear breaking problems.... - Page 2

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!

SSDiv6 · 08-14-2007, 09:39 AM

Are you using a solid spacer or a crush sleeve in the pinion? If you have a crush sleeve, switch to a solid spacer with shims.

Jeff Niceswanger · 08-14-2007, 09:47 AM

Eric,we finally gave up and did put a nine inch in.But back when we ran a 5.57 gear we never broke any gears.It wasn't until we started running a 6.00 gear and the pinion got so small that every 50 runs or so it would bust one.We set them tight, loose, bought MW caps,T/A cover etc.... Alot of it has to do with weight.We know alot of folks with the lighter class cars that run a twelve bolt and punish the crap out of them and they don't have problems.But when you get over 3100 or 3200 pounds ( our car is @ 3255 in F) they are on the edge,especially with the steep ratios. Buy the way I have a 5 gallon pail of that Redline Shockproof 140w gear oil that never has been opened setting here collecting dust. Anybody give me 50 bucks ?

ericsz · 08-14-2007, 09:57 AM

I am in fact using a Crush Sleeve, the car also has a Richmond Mini Spool in it.

Mark Ruset · 08-14-2007, 10:53 AM

Eric I've been running a 12 bolt 5:14 Richmond street gears for the past 3 years and have had no problems I run a 68 camaro in G automatic and launch about 2600 rpm. I feel the key to longevity with a 12 bolt is pinion depth. You ensure that both the ring and pinion are getting the most contact when you are dead on this, will make for long life.

SSDiv6 · 08-14-2007, 01:23 PM

Get rid of the crush sleeve and use a spacer kit with shims. This will maintain the pinion depth. The shock everytime you drop the clutch will have an effect on the crush sleeve.

JDEMARZO · 08-14-2007, 02:57 PM

I used a street gear with a 31 spline axle in a G/SA (3250 lbs) for 15 years with no breakage, same gear set. Leaving on the converter is different than leaving on a trans brake. I have a A/SA with a pro gear because all the other A/SA cars ripped the street gears out within 10 runs on a 2-step or foot braking not even a trans brake.

I really do no think you can use a street gear with a trans brake.... Too much stress to the gear set on the launch. If A/S (leaving @ 7000 plus ) and super stock cars using trans brakes are using a 12 bolt your combo should be fine with a pro-gear with the trans brake. Buying pro gears is lot cheaper than changing the rear to a 9 inch.

J.DeMarzo

08-13-2007, 04:00 PM	#11
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, 03:10 AM	#12
John Duzac Member Join Date: May 2005 Location: Covington, La Posts: 310 Likes: 61 Liked 85 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, 08:33 AM	#13
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, 08:59 AM	#14
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!

08-14-2007, 09:39 AM	#15
SSDiv6 VIP Member Join Date: Feb 2003 Location: Glendale, Arizona Posts: 2,991 Likes: 693 Liked 1,457 Times in 543 Posts	Re: 12 bolt gear breaking problems.... Are you using a solid spacer or a crush sleeve in the pinion? If you have a crush sleeve, switch to a solid spacer with shims.

08-14-2007, 09:47 AM	#16
Jeff Niceswanger Senior Member Join Date: Jul 2003 Posts: 778 Likes: 596 Liked 852 Times in 299 Posts	Re: 12 bolt gear breaking problems.... Eric,we finally gave up and did put a nine inch in.But back when we ran a 5.57 gear we never broke any gears.It wasn't until we started running a 6.00 gear and the pinion got so small that every 50 runs or so it would bust one.We set them tight, loose, bought MW caps,T/A cover etc.... Alot of it has to do with weight.We know alot of folks with the lighter class cars that run a twelve bolt and punish the crap out of them and they don't have problems.But when you get over 3100 or 3200 pounds ( our car is @ 3255 in F) they are on the edge,especially with the steep ratios. Buy the way I have a 5 gallon pail of that Redline Shockproof 140w gear oil that never has been opened setting here collecting dust. Anybody give me 50 bucks ?

08-14-2007, 09:57 AM	#17
ericsz Member Join Date: Jul 2007 Posts: 140 Likes: 0 Liked 0 Times in 0 Posts	Re: 12 bolt gear breaking problems.... I am in fact using a Crush Sleeve, the car also has a Richmond Mini Spool in it.

08-14-2007, 10:53 AM	#18
Mark Ruset Member Join Date: May 2006 Location: Southwest Florida Posts: 250 Likes: 23 Liked 34 Times in 24 Posts	Re: 12 bolt gear breaking problems.... Eric I've been running a 12 bolt 5:14 Richmond street gears for the past 3 years and have had no problems I run a 68 camaro in G automatic and launch about 2600 rpm. I feel the key to longevity with a 12 bolt is pinion depth. You ensure that both the ring and pinion are getting the most contact when you are dead on this, will make for long life. __________________ Mark Ruset 2048 STK

08-14-2007, 01:23 PM	#19
SSDiv6 VIP Member Join Date: Feb 2003 Location: Glendale, Arizona Posts: 2,991 Likes: 693 Liked 1,457 Times in 543 Posts	Re: 12 bolt gear breaking problems.... Get rid of the crush sleeve and use a spacer kit with shims. This will maintain the pinion depth. The shock everytime you drop the clutch will have an effect on the crush sleeve.

08-14-2007, 02:57 PM	#20
JDEMARZO Junior Member Join Date: Mar 2003 Posts: 72 Likes: 0 Liked 0 Times in 0 Posts	Re: 12 bolt gear breaking problems.... I used a street gear with a 31 spline axle in a G/SA (3250 lbs) for 15 years with no breakage, same gear set. Leaving on the converter is different than leaving on a trans brake. I have a A/SA with a pro gear because all the other A/SA cars ripped the street gears out within 10 runs on a 2-step or foot braking not even a trans brake. I really do no think you can use a street gear with a trans brake.... Too much stress to the gear set on the launch. If A/S (leaving @ 7000 plus ) and super stock cars using trans brakes are using a 12 bolt your combo should be fine with a pro-gear with the trans brake. Buying pro gears is lot cheaper than changing the rear to a 9 inch. J.DeMarzo