[Melrose RS]

I’m planning to swap my car over from 4spd and 12 bolt 2.73 posi to 200-4r and 3.73 posi so will need a new 3series carrier and gears.
I see that Jegs offers both under their own brand name. Are these of good quality?

I’d very much like to try the assembly/setup myself and would put a value on parts that go together well, instead of lowest price.
This is and will always be a driver car, 75-80mph sustained highway often, so not building the rear for the strip.
Thanks, Tom

 

[Vega$69]

Eaton
Yukon
Auburn

Some don't like the Auburn because it can't be rebuilt but for a street car I have had no issues with them.

 

[Larry Madsen]

This is what I purchased. I had a local shop do the install. I'm happy with it.

DSC_2025 by Larry Madsen, on Flickr
DSC_2026 by Larry Madsen, on Flickr

 

[ilikeike]

Eaton Trutrac Detroit Locker 913A315 Eaton Detroit Truetrac Differentials | Summit Racing

Made in USA, US Gear lighting series = no break in. 3.73 they have the standard non-polished series also for less $ US gear website

 

[rp930]

I’ve had good results with Motive Performance gears.

 

[Vega$69]

OP is asking about carrier.

 

[Melrose RS]

Carrier and gears.

 

[Fred Mertz]

I went with a Moser 12 bolt axle assy with a True-Trac 3:73 geared posi. All I had to add was the brakes.

 

[350sshugger]

I used the factory carrier, but installed US gears and installation kit. Their kit has the better Timken bearings. It’s detailed in my build thread on page 45 I believe. Setup went well and gears make no noise. At 700 miles I changed the fluid and the wear pattern looks excellent.

GM 12 Bolt Car 8.875

US Gear manufactures ring and pinion gears for the high performance and motorsports markets. High quality gears made with pride in the USA.

www.usgear.com

edit: I forgot I had this thread as well in case it is helpful. I included my shopping list. 12 bolt overhaul opinions

 

[rp930]

OP is asking about carrier.

And gears.

 

[Farm Boy]

Popular Differential Options Explained
The Truetrac carrier looks like a good option.

Detroit Truetrac - Helical-gear limited-slip (worm differential) is the modern replacement for the classic clutch-type posi. Under normal light throttle driving conditions, a Truetrac operates much like a standard open differential, allowing the rear wheels to rotate at slightly different speeds for smooth cornering. However, when accelerating (torque applied), the six helical-gears inside the unit smoothly and quietly engage, applying torque to both rear wheels equally, maximizing traction (think two equal length black stripes). Unlike a traditional clutch-type posi, a Truetrac requires no special oil additive or maintenance. With silky-smooth positive operation and no components to wear out, the Truetrac maintains day-one performance for the life of the unit.

 

[57vette]

I'm not there yet but moving slowly down a somewhat similar path. I'm going from a 8.2" 10-Bolt to a 8.5" 10-Bolt 72 Nova donor multi-leaf rear which I already have. I also already have the Hotchkis 1.5" leafs and shackles sitting in the parts shed along with some temporary KYB shocks and a set of subframe connectors. I've heard nothing but good stuff about Motiv gears so I bought a brand new 3.42 ring and pinion set (car has a 4-speed), their premium line which I think is made in Italy. I'm not sure about their "regular" line of gears when it comes to where they are made.
I have several friends who spend a lot of time at the track and many have switched from "conventional" style Eaton Posi limited-slip clutch setups to Eaton True-Tracs although they ran their clutch rears pretty hard, a few of them are making 750-850 RWHP and it took a while before the clutches gave out. They love the true-trac with its all gear internals. For street use and occasional hits at the track, the Yukon gets pretty good marks so that's probably where I'll be going although some people have said that the Yukon can be a little noiser than the TrueTrac. Typically its a extra $250 for a TrueTrac over a Yukon DuraGrip, so its all about your budget.
I'm tempted to use 30 spline axles but several friends who know me and my driving habits keep telling me that the 28's would be OK bc some people use them in a Ford 9" and are OK for street use. If I'm buying new axles and bearings, etc., I think I might as well go 30 which is the same as a 12-bolt. I don't think there's much difference in price on the axles/bearings.

 

[ilikeike]

I even put a Trutrac in my daily driver GMC z71 truck, ditched that crappy GM Eaton rpo code#G80 locker.

 

[Melrose RS]

I'm not there yet but moving slowly down a somewhat similar path. I'm going from a 8.2" 10-Bolt to a 8.5" 10-Bolt 72 Nova donor multi-leaf rear which I already have. I also already have the Hotchkis 1.5" leafs and shackles sitting in the parts shed along with some temporary KYB shocks and a set of subframe connectors. I've heard nothing but good stuff about Motiv gears so I bought a brand new 3.42 ring and pinion set (car has a 4-speed), their premium line which I think is made in Italy. I'm not sure about their "regular" line of gears when it comes to where they are made.
I have several friends who spend a lot of time at the track and many have switched from "conventional" style Eaton Posi limited-slip clutch setups to Eaton True-Tracs although they ran their clutch rears pretty hard, a few of them are making 750-850 RWHP and it took a while before the clutches gave out. They love the true-trac with its all gear internals. For street use and occasional hits at the track, the Yukon gets pretty good marks so that's probably where I'll be going although some people have said that the Yukon can be a little noiser than the TrueTrac. Typically its a extra $250 for a TrueTrac over a Yukon DuraGrip, so its all about your budget.
I'm tempted to use 30 spline axles but several friends who know me and my driving habits keep telling me that the 28's would be OK bc some people use them in a Ford 9" and are OK for street use. If I'm buying new axles and bearings, etc., I think I might as well go 30 which is the same as a 12-bolt. I don't think there's much difference in price on the axles/bearings.

Sounds like you are describing the parts in my shed! Hotchkis and subframe connectors…
I had the rear rebuilt about 10 years ago (a few thousand miles) and the original axles were mint(no abuse ever) so i won’t have to change those.

 

[DOUG G]

Eaton LS
Motive gears

NO Richmond....noisy. (many reports and personal exp.)

 

[rp930]

This. ^^^^

 

[Melrose RS]

How many splines on original 1967 12 bolt axles?

 

[StevieBB54]

I'm not there yet but moving slowly down a somewhat similar path. I'm going from a 8.2" 10-Bolt to a 8.5" 10-Bolt 72 Nova donor multi-leaf rear which I already have. I also already have the Hotchkis 1.5" leafs and shackles sitting in the parts shed along with some temporary KYB shocks and a set of subframe connectors. I've heard nothing but good stuff about Motiv gears so I bought a brand new 3.42 ring and pinion set (car has a 4-speed), their premium line which I think is made in Italy. I'm not sure about their "regular" line of gears when it comes to where they are made.
I have several friends who spend a lot of time at the track and many have switched from "conventional" style Eaton Posi limited-slip clutch setups to Eaton True-Tracs although they ran their clutch rears pretty hard, a few of them are making 750-850 RWHP and it took a while before the clutches gave out. They love the true-trac with its all gear internals. For street use and occasional hits at the track, the Yukon gets pretty good marks so that's probably where I'll be going although some people have said that the Yukon can be a little noiser than the TrueTrac. Typically its a extra $250 for a TrueTrac over a Yukon DuraGrip, so its all about your budget.
I'm tempted to use 30 spline axles but several friends who know me and my driving habits keep telling me that the 28's would be OK bc some people use them in a Ford 9" and are OK for street use. If I'm buying new axles and bearings, etc., I think I might as well go 30 which is the same as a 12-bolt. I don't think there's much difference in price on the axles/bearings.

Mike, I have the 8.5 10 bolt with 30 spline MG axles with Auburn posi I think. Mines just a street car so I am sure it is more than adequate. My neighbor has a 67 with a 427 and 10 bolt and it has spent most of its life as a drag car, it is still holding up but it is a whiner lol.
Any chance you can send me a pic of your Hotchkiss rear springs and shakles in your shed? I have 2" blocks and want to get rid of them, but Im not sure what leaf springs the PO installed. Id like to compare the differences before I order another set of springs.

 

[57vette]

How many splines on original 1967 12 bolt axles?

AFAIK... original 1st gen Camaros with a 12-bolt have 30 splines.