3.91 with jre posi mod

[CHRI55]

I have a stock a6 rear end. A homie trying to sell me a gpi built diff with 3.91s and jre posi mod for 700 and my stock diff. Pros and cons of going jre other then tru track

[Black_SS10]

$700 plus your diff? In my opinion, that's a lot. I've bought and sold complete used diffs with gears and trutracs for around that price. For prolly a few hundred more you could put gears and a trutrac in yours. I did a diff with new bearings, new 3.91 gears, new trutrac, and labor for around $1200.

[CHRI55]

Originally Posted by Black_SS10

$700 plus your diff? In my opinion, that's a lot. I've bought and sold complete used diffs with gears and trutracs for around that price. For prolly a few hundred more you could put gears and a trutrac in yours. I did a diff with new bearings, new 3.91 gears, new trutrac, and labor for around $1200.

The rear out of his car only have about 500 miles on it.. and I was qouted 1300 without tru track. 450 labor.. about 500 for the gm gear.. 250 for a rebuild kit..my area don't have many reliable options

[Black_SS10]

I guess it would be up to you then. Although, why does he want to sell/trade his, since it has such low miles?

You can get just the 3.91 ring and pinion for cheaper than $500. Also if your bearings are good, a half install kit is cheap. If you even need it. You may be able to resuse your shims. I rebuilt mine entirely, because I'm OCD like that.

[CHRI55]

Originally Posted by Black_SS10

I guess it would be up to you then. Although, why does he want to sell/trade his, since it has such low miles?

You can get just the 3.91 ring and pinion for cheaper than $500. Also if your bearings are good, a half install kit is cheap. If you even need it. You may be able to resuse your shims. I rebuilt mine entirely, because I'm OCD like that.

He's going whipple and nitrous 416 so he gearing down to a 3.45 I think. Im going 416 aannd centri eventually but as of now I'm cam only. And I was looking at thre kit that gpi has for 515 with the extra parts. That's what the builder recommended

[Black_SS10]

You really only need the ring and pinion. Sold here for half the price.
https://paceperformance.com/i-103067...-gear-kit.html

The factory gasket is reusable. Grab some Ac Delco OR fluid of choice that already has the friction modifier in it. As long as your bearings are good, then realistically all you need is the ring, pinion, and fluid. It should take less than 5 mins for a tuner to update your tune for the gear change.

I know I plan on going TT soon. So I have my factory diff with 3.45 sitting in my garage. I have an extra trutrac for it and it will get rebuilt. Then I can just swap diffs when I am ready. That may be a solution for you as well.

[CHRI55]

Originally Posted by Black_SS10

You really only need the ring and pinion. Sold here for half the price.
https://paceperformance.com/i-103067...-gear-kit.html

The factory gasket is reusable. Grab some Ac Delco OR fluid of choice that already has the friction modifier in it. As long as your bearings are good, then realistically all you need is the ring, pinion, and fluid. It should take less than 5 mins for a tuner to update your tune for the gear change.

I know I plan on going TT soon. So I have my factory diff with 3.45 sitting in my garage. I have an extra trutrac for it and it will get rebuilt. Then I can just swap diffs when I am ready. That may be a solution for you as well.

Thx.

[Greenhornet2]

I'd trade him and give him like 300. That's worth not having to open up the diff and just swap it in to me. Cons of the jre is you still have the stock spider gears which are a weak point. If it breaks those will likely be what breaks. All the posi mod does is driven up the posi so you don't check a one legger burnout. So swap it, break it then do a tru trac, or zl1 diff

[CHRI55]

Originally Posted by Greenhornet2

I'd trade him and give him like 300. That's worth not having to open up the diff and just swap it in to me. Cons of the jre is you still have the stock spider gears which are a weak point. If it breaks those will likely be what breaks. All the posi mod does is driven up the posi so you don't check a one legger burnout. So swap it, break it then do a tru trac, or zl1 diff

That was the plan. Wanted to do a zl1 diff, and 6l90 swap at the same time. give thst they both hold long enough lol

[Black_SS10]

There's plenty of fast people running a factory SS diff setup.
Drivetrain shock and wheel hop are what break things.

[CHRI55]

Originally Posted by Black_SS10

There's plenty of fast people running a factory SS diff setup.
Drivetrain shock and wheel hop are what break things.

So the posi mod is good?

[Black_SS10]

Originally Posted by CHRI55

So the posi mod is good?

If by good, you mean it works? Then yes. The posi mod is just clutches for the diff. The diff would have to come apart to install. Why not just put something better in? Such as a Trutrac. There are no clutches to wear out in a Trutrac. Unlike a stock unit or even the posi mod.

[CHRI55]

Originally Posted by Black_SS10

If by good, you mean it works? Then yes. The posi mod is just clutches for the diff. The diff would have to come apart to install. Why not just put something better in? Such as a Trutrac. There are no clutches to wear out in a Trutrac. Unlike a stock unit or even the posi mod.

If I had to go in it I would. But I dont.. im buying his complete differential unopened that he got from gpi.. if li end up going in it later down the line, I will