Building my 10 bolt, best steps and worth it?

[Josh69]

I have a '71 Nova 10 bolt with the 8.5" ring gear that I was planning on putting in my '69 Firebird. I'm trying to decide if it's worth it to rebuild and use, or just get a new complete axle. I don't want to cheap out, but I want to be economical.

The housing I have is complete, I haven't opened it since I'm not an expert on rear-ends by any stretch. It spins freely, it's an open diff.

My concern is what kind of shape does the housing and tubes have to be in to justify re-using? Mine had quite a few areas of flaking off rusty layers. On the cast center I'm not concerned, but the tubes look like the surface of a golf ball/the moon, whatever.

I was going to blast it, expoxy seal it and paint it then have a local shop install a set of forged or alloy 30 spline axles, a Trutrac, etc.

Is it a requirement to have new bearing housings welded on and something like Torino bearings to use the 30 splines?

At that point, it starts to get right in the total cost neighborhood of a brand new Moser 12bolt.

[rohrt]

Some where on this site I beat this question to death. You end up spending around the same amount of money upgrading any rear weather ist a 10 bolt 12 bolt or 9 inch ford. If you have the 8.5 10 bolt then I would use it. I would not go with the true track but thats just me. I would use an Eaton Posi, US Gears, 30 spline Axles and Ford axle bearings. I should be strong enough for what ever you plan on doing with it.

[Josh69]

Do the ends need to be machined for a new bearing carrier to run the ford bearings?

What's your basis for choosing Eaton over Trutrac?

I have the 10 bolt sitting at home, but wonder at what point does it get too crusty and worn to reuse...for example the tubes, how thick are they and what goes beyond cosmetic and becomes structural concern?

[Midnight68]

I have a axle out of a 72 Nova in my 68 camaro. I got the axle for 30 bucks at the junk yard, i took everything out wire brushed and painted it. I stole the auburn posi out of my 90 full size blazer. In 89 the 10 bolts went to 30 spline axles so the carriers fit right in the old axle. I got moser axles for like $300, they are basically 12 bolt axles but the button on the end is smaller. I got all new bearings and new gears for like $200. If you are really on a budget you could get used gears and a used gm posi for cheaper. Stay away from the true track. You do not have to change any of the bearing carriers to run 30 spline axles. I doubt it would have rusted enough to be a structural concern.

[big gear head]

What do you plan on doing with this car? If it is a drag racer then the Eaton is the way to go. If it will be used for cornering then the Truetrac will be smoother. If you plan on using slicks and launching hard then the housing needs more prep before you start to build it. The axle tubes need to be welded to the center casting with nickel rods by someone who knows houw to weld cast iron. The rusty tubes shoiuld not be a problem if this will be a street car, but if it will be a fast drag racer then a Moser 12 bolt would be best. The 30 spline axles can be used with c clips and the stock houisng ends. If you go with the Ford axle bearings then you will need custom axles and the housing ends will have to be welded on using a housing fixture.

[rohrt]

I have hear a few bad things abou the true track but I don't recall what the problem were. I remeber moser quoted me 400 for axles with the ford bearings already on and the ends I think.

I stole the auburn posi out of my 90 full size blazer. In 89 the 10 bolts went to 30 spline axles so the carriers fit right in

I didn't know that. I wouldn't want a auburn but if I was on a budget that is a slick trick.

[Josh69]

The car is a street car, 18" street tires, Z rated, no slicks, no hard launches, mostly spirited driving and commuting and hitting the twisties for fun. No track time.

My concern is parts longevity from daily use and occasionally wringing it out, but not really abuse. The car may very well end up with a torque monster 455 or stroked 400 so whatever I do has to live behind that on the street.

So the truetrac is smoother?

So all I need is a diff/carrier, gears, axles and a set up kit and I should be able to have a competent shop put it together?

Do I need to reweld the tubes for a street car? I'd hate to get this far into it and have them warp it...then I'd have to find another housing and the whole time I'll be pissed I didn't just get the Moser 12.

I budgeted for the build, but you know how it goes, every time you turn around something else costs you.

[big gear head]

The plug welds that hold the axle tubes in place are pretty bad on the 8.5 housings. I usually weld the tubes on any 8.5 that I build to sell because you never know what someone might do with it. If it will be used for street driving and you can controll the wheel hop then it might be all right like it is.

The Truetrac will be good for this, but the Eaton will also work. The carbon fiber clutches that are used in the new Eaton posi will last as long as the car, or much longer.