12 bolt rearend

[SB'72]

Looking at upgrading my 12 bolt rearend (1972 C/10). Looking at getting the Trutrac with 3.42 gears, also thinking about upgrading to rear disc brakes as well. Currently have 3.08 gears with drum brakes. Any ideas on the brakes, and thoughts/feedback on the gears and Trutrac.


Thanks

[Ole Greenie]

Originally Posted by SB'72

Looking at upgrading my 12 bolt rearend (1972 C/10). Looking at getting the Trutrac with 3.42 gears, also thinking about upgrading to rear disc brakes as well. Currently have 3.08 gears with drum brakes. Any ideas on the brakes, and thoughts/feedback on the gears and Trutrac.


Thanks

I too am looking to swap 3.08 gears for a 3.42 set with LS (Limited Slip) so this thread interests me. I chose the 3.42 due primarily to having an OD tranny. The 3.42 set seems to be a good gear as GM still uses it in their new trucks (10 bolt) today. Kind of torn between the Auburn LS and Detroit LS though. subscribed...

[71meangreenc10]

Just put in 3.42 in my 12 bolt, also did the camaro calipers, works well so far.

http://67-72chevytrucks.com/vboard/s...d.php?t=518599

Smitty

[406 Q-ship]

Originally Posted by SB'72

Looking at upgrading my 12 bolt rearend (1972 C/10). Looking at getting the Trutrac with 3.42 gears, also thinking about upgrading to rear disc brakes as well. Currently have 3.08 gears with drum brakes. Any ideas on the brakes, and thoughts/feedback on the gears and Trutrac.


Thanks

Here is the Summit link to the Truetrac

http://www.summitracing.com/search/B...c&autoview=SKU

[BossHogg69]

I have a Truetrac, 3.73's, Moser axles and Moser diff cover/brace in my 12 bolt also. Camaro calipers/Impala SS drilled & slotted rotors. I haven't driven it yet with the Truetrac, but when I was doing my shopping, everything I heard and read about the Truetrac was in line with what I needed. Try doing some searching on Team Chevelle (www.chevelles.com), a lot of those guys run the Truetrac in their car 12 bolts.

I will say that I have run the Auburn HP Series LSD in another truck I had and it performed well also.

And what good would a post be without pics???

[Already Gone]

Originally Posted by BossHogg69

I have a Truetrac, 3.73's, Moser axles and Moser diff cover/brace in my 12 bolt also. Camaro calipers/Impala SS drilled & slotted rotors. I haven't driven it yet with the Truetrac, but when I was doing my shopping, everything I heard and read about the Truetrac was in line with what I needed. Try doing some searching on Team Chevelle (www.chevelles.com), a lot of those guys run the Truetrac in their car 12 bolts.

I will say that I have run the Auburn HP Series LSD in another truck I had and it performed well also.

And what good would a post be without pics???

Adam, what is the purpose of the diff cover brace, besides it looking real cool ?

[Already Gone]

I've read and researched tons of stuff on diffs and I agree, a 4L60E or 700R4 with a 3:42 gear with Tru-Trac is a great combo for all around use.

[BossHogg69]

The two allen head studs on each side of the 'Moser' logo in the pic above go all the way into the gear case and adjust up against the bearing caps on each side of the differential. They are supposed to stabilize the caps and keep them from 'walking' or moving around under load.

[RexDodge]

There is a member on here that makes the brackets to bolt the Camaro and Cadillac calipers onto the 12 bolt. That's on my list for next winter.

[AusTx68]

Originally Posted by RexDodge

There is a member on here that makes the brackets to bolt the Camaro and Cadillac calipers onto the 12 bolt. That's on my list for next winter.

Right, here is the link: http://67-72chevytrucks.com/vboard/s...d.php?t=382633

I used Captain's brackets for my rear brakes. Came out nice and they work great. I'm using an Eaton posi with 4:11s and a 700r4. I wouldn't change a thing.

[dznucks]

I am currently working on a similar project.

12 bolt with Eaton TruTrac and 4.10's. Using Cadillac D-52 calipers, Astro Van Rotors, and Captain Fabs brackets.

I got the gears shimmed correctly, just need to clean it for final assembly and install it.

[dennislbrooks]

I have been running 82 camaro calipers on the rear for a few years. They perform well but they do turn the emergency brake into a parking brake. To get mine to hold at a safety check beforee I shift into drive, I need to depress the pedal then pull the lever handle as much as I can get. I can just pass the test.

The foot parking brake may apply a little more pull. How did others fare on this?

It is kind of a toss to me on disc on rear. My 2006 WT 4wd has drums. My former 2002 Z71 4wd had disc.

[RexDodge]

Originally Posted by dznucks

I am currently working on a similar project.

12 bolt with Eaton TruTrac and 4.10's. Using Cadillac D-52 calipers, Astro Van Rotors, and Captain Fabs brackets.

I got the gears shimmed correctly, just need to clean it for final assembly and install it.

Not to pirate the thread but what year on those Astro van rotors?

[dznucks]

Not to pirate the thread but what year on those Astro van rotors?

1992-2002 AWD Astro Van. This is one of the setups Captain Fab offers brackets for. There is a lengthy thread in the Vendor section.

For anyone looking for these rotors, Summit currently has a set of Astro van drilled and slotted rotors on clearance for $50 each. I almost bought them, but then i would have to change the fronts to drilled and slotted too.

[SB'72]

Thanks for the ideas and feedback. Anyone know of a complete disc brake kit that works on the truck 12 bolt. By the way I have a TH350, and thought that 3.73 in the rear would be to low for me. What do you think about the change from 3.08 to 3.42, will it be a noticeable jump?

[Jay W]

This is a copy of an email from the guy i bought my posi from.

"Jason-
We ship to Canada daily. Here is what we can do for you:

$450 - GM 12-Bolt Truck Eaton Posi Unit - 30 Spline
$135 - GM 12-Bolt Truck Ring & Pinion (3.73 Ratio)
$65 - GM 12-Bolt Truck Master Bearing/Installation Kit
-------------------------------------------------------------------------------------
$100 - SHIPPING via UPS Worldwide Standard (3-5 Days)
-------------------------------------------------------------------------------------
$750 - TOTAL

You would have a flat $10 brokerage fee and the taxes would run $20-$30.

Let me know if you have any other questions.

Thanks,
BRYDON
641-751-8060
staticz2229@gmail.com"


I think shipping to the US was free. Great product for a great price. I found his stuff on ebay.

[oldspowered67C10]

Tru-trac is a nice traction device for the street but if Im not mistaken its only offered in 12-bolt truck in the 3.73-up carrier. If you want 3.42 gears you gonna have to use a clutch or cone type. Too bad, I wanted a tru-trac but 3.73s are too tall for my th400 and 28" tires

[SB'72]

Well that sucks, I came across Moser's website, and they offer the 3.42 gear set/trutrac for their 12 bolt. Since theirs is a custom rearend explains why they are probably able to offer it.

[jtp67-72]

Just had Moser build this one....true trac....3.73.....33 spline.....Grand sport brakes...kore 3 brackets....

Here's link to board member's kit for truck c5 kit.....I bought one ...but then changed to big ford bearing rear...sold mine...nice kit.....

http://67-72chevytrucks.com/vboard/s...d.php?t=415021

here's pic of kit also...........jim

[71meangreenc10]

Originally Posted by SB'72

Thanks for the ideas and feedback. Anyone know of a complete disc brake kit that works on the truck 12 bolt. By the way I have a TH350, and thought that 3.73 in the rear would be to low for me. What do you think about the change from 3.08 to 3.42, will it be a noticeable jump?

I went from 3.08 to 3.42 along with 350 to 700R4 and the truck is alot more responsive.

The camaro calipers work well on the 12 bolts.

Smitty

[SB'72]

Jp that looks awesome, thanks for the info.
Posted via Mobile Device