12 bolt rear end rebuilt help

[flamingbig10]

I plan on completely rebuilding the 12bolt in my truck with new bearings, seals, 3.73 ring and pinon, posi traction carrier but I don't know what brand parts to use and what type of ring a carrier to use

[68 TT]

Originally Posted by flamingbig10

I plan on completely rebuilding the 12bolt in my truck with new bearings, seals, 3.73 ring and pinon, posi traction carrier but I don't know what brand parts to use and what type of ring a carrier to use

Find a local shop that rebuilds rear ends and has a good reputation and take it to them to do it. It won't cost you much more than the parts and you will know the pinion preload and the backlash on the gears are set properly. These are very easy to mess up if you do not have experience doing it.

You may be better off looking for a 12-bolt with the gears and posi you want then having it freshened up. A new posi carrier will run you $400 plus $300 for the gears and bearing kit to install them.

I see posi 12-bolts on CL for around $300 so that might save you a bunch of money if you can find one local.

[flamingbig10]

A guy I work with rebuilds rear ends all time so I got that part covered.
I do now how high ring & pinons, and carriers are but I want brand new stuff

[nlped]

I bought my Brand New Auburn posi unit off of Ebay (actually came from Driveshaftsource.com) for $295 shipped...great deal! I bought my R&P and install set from Nationaldrivetrain.com for $227 shipped. I then bought the new axle bearings and seals locally for about $35. And I paid a guy who has built 3 other rearends for me $100 to install everything. I did take the rearend out from under the truck and deliver it to him though. So for roughly $550, I have a new Positrac 12 bolt rearend.

Now that being said, I did also buy an aluminum diff cover too , just for some coolness factor, but it also allowed for another 1/2 quart of gear fluid and it has a drain plug in it, so I won't have to pull the cover to change the fluid Oh yeah, I also put the McGaughy 13" rear brake kit on it too It's back under the Blazer, but I haven't gotten around to lowering the front yet, so it looks like a drag car that just left the line...front end is about 12' higher than the rear.

[silvereagle07]

Here is an article I found on rebuilding a GM12t. I am interested in doing the same for my truck. I'm want to use 3.42's and the Detroit trutrac but the don't make them only 37.3 and up.
http://www.classictrucks.com/tech/10...ild/index.html

[68 TT]

Originally Posted by nlped

I bought my Brand New Auburn posi unit off of Ebay (actually came from Driveshaftsource.com) for $295 shipped...great deal! I bought my R&P and install set from Nationaldrivetrain.com for $227 shipped. I then bought the new axle bearings and seals locally for about $35. And I paid a guy who has built 3 other rearends for me $100 to install everything. I did take the rearend out from under the truck and deliver it to him though. So for roughly $550, I have a new Positrac 12 bolt rearend.

Now that being said, I did also buy an aluminum diff cover too , just for some coolness factor, but it also allowed for another 1/2 quart of gear fluid and it has a drain plug in it, so I won't have to pull the cover to change the fluid Oh yeah, I also put the McGaughy 13" rear brake kit on it too It's back under the Blazer, but I haven't gotten around to lowering the front yet, so it looks like a drag car that just left the line...front end is about 12' higher than the rear.

You got a great deal on that Posi carrier. The same source is now $340 plus $25 shipping. Still not a bad price but getting it shipped for under $300 was a steal.

[nlped]

Originally Posted by 68 TT

You got a great deal on that Posi carrier. The same source is now $340 plus $25 shipping. Still not a bad price but getting it shipped for under $300 was a steal.

Exactly why I bought it. I searched around after finding this one and the closest I could get was about $350 shipped. Every once in a while Ebaying pays off...every once in a while.

[flamingbig10]

I've also found a complete kit for 700 includes gears, carrier, and a master install kit
http://cgi.ebay.com/ebaymotors/Aubur...Q5fAccessories

[nlped]

That, certainly, isn't a bad deal! I lucked up on mine, but I still had to piece everything together after that. I have had several Auburn diffs in Mustangs and they have done FANTASTICALLY, so that's why I went with one for the "Bull". It seems like a large expense up front, but if you do it right the first time, you won't be doing it again...and that is a major financial factoid! Do it right the 1st time & you won't have to do it again!

Semper Fi!

[flamingbig10]

I guess its a done deal I will be ordering the kit, then a rear disc kit and a disc/disc master cylinder, booster, and proportional valve, and so on

[nlped]

^^^I totally understand that! I have everything you just mentioned sitting here in my garage floor

[68 TT]

Originally Posted by flamingbig10

I guess its a done deal I will be ordering the kit, then a rear disc kit and a disc/disc master cylinder, booster, and proportional valve, and so on

For a truck I would look for a carrier like the Detroit Truetrac that does not use clutches.

If you get in a situation where one wheel has traction and the other does not then you can tear up the clutches in a typical posi very quiclkly.