12 bolt installation

[Doug]

I have a new Eaton series 4 carrier that I want to install in my 12 bolt with a new set of gears.

I have never done this before but really want to learn.

How bad is it? Anyone know of a good book that might help me?

[jim sanders]

I am a drum to drum type guy Doug.. maybe Flyin' or pro70 will help

[pro70z28]

I put aftermarket gears in a 12 bolt once back in my youth. As I recall it wasn't all that difficult, just time consuming. Keep adjustin' shims 'til you get a nice pattern on the gears, that's about all I remember. Bought the 9" for the "Z" from Danny Miller already set-up...... I cheated.

[jim sanders]

yep.. Danny for gears...

[flyinhillbilly]

you'll need a dial indicator to set backlash. your gear set should come with a sheet showing the pattern you want, the hardest part is getting the carrier bearings preloaded right ( the factory has a spreader, that's what the holes on either side of your diff are for) it's not too hard, just takes patience.

[Doug]

Thanks man, I think i'll see if I can find some directions on installing it before I start. Then I'll go at it.

I have the new diff.
By the way Toms differentials.GREAT guy to deal with. The Eaton that I got from him for $350 was something like 425 through summit.

I still have to get the gears and an install kit.

I have a dial indicator and base.
Wort case is that I can't get it and have to take it somewhere.

Thanks for the help.

[jim sanders]

this is what is so cool about this place and pro 60's site... real world answers to real questions.. no hype, no lies, no BS....

[Leon]

Seems to me that you need a 4 series case to install 4 sumpthin gears on 12 bolts.

[flyinhillbilly]

aren't a 4 series and a series 4 the same?^^^^ see 1st post^^^

[Doug]

Seems to me that you need a 4 series case to install 4 sumpthin gears on 12 bolts.

It's not the case, it's the carrier. I did buy a series 4 carrier.

I have also learned the difference is in the width of the ring gear.
You can buy a 4.10 for a series 3 carrier from richmond it's a 4.10 "thin"

There may be more to it than that but..... I dunno..

I know that I didn't do my homework all that well because i thought (there are always problems when I do that) I could get a 3.90 gear for this carrier and I can't. At least not an American made one that I know of from Richmond or US Gear.

That's ok though, I will use the 4.10 and a 28" tire instead of a 26" tire and still trap about 6300 rpm with the new motor.
Then I can save my pennies for 4 speed automatic that's beefy enough for me.