Edit: sorry sticky answered most of my questions.

 

I would buy a late model ten bolt that has 28 spline axles. I believe 91-02 rears have them, with 91-92 being thirdgen rears obviously and 93-97 being first generation of the 4th gen rears and 98-02 being last generation. There are slight differences between the 4th gens.

Ones from ls1 cars have bigger brake rotors and could come with zexel torsen diffs which i like. Worm gear type so no clutches to wear out like old auburns and eatons, and no cones like 9 bolts. Ls1 rears are slightly narrower than early 4th gens. Just a wee bit.

Both will make your wheels stick out alittle so keep that in mind.

I wouldnt spend too much money on the rear either. Maybe a diff girdle/cover but not much else. If it blows buy another drop out. Unless you can put in diffs and gears yourself

Ls1 rears with an auto trans can handle decent hp in a somewhat light car

 

Thanks for the info. I have a lead on here for a posi disc 3.27 9 bolt with the cast calipers. For 200 bucks. My motor makes close to 400hp and I don't go to any tracks or plan to run slicks. Would this be enough? Also what would you expect to pay for an ls1 cars rear?

 

Oh and how can I tell which posi unit is in it? Thanks.

 

9 bolts are ok if not worn. If cones inside are worn they will lose posi ability after some use. My rear did this. I also broke that 9 bolt with 300 hp...this may not have been typical but it didnt last and replacement parts are rare

My 4th gen 10 bolt has held 800 hp but relatively soft launches at track. Not all survive this abuse but i like the worm gear style of posi. Great for street apps.

You can tell by looking at them. Would need to pop cover off but most 99-02 should have zexel torsen diffs from the SS or trans am ws6 models. Other models may not have them.

You can get 4th gen rears from 200-400$ but i would not pay more than 300-325 for typical 3.23-3.42 rear that has complete brakes. Rear with no brakes is kinda worthless imo but would bring much less money. 100-150 perhaps.
I bought a brakeless 2.73 rear for 60$. Been 9.73 in 1/4 mile. Again, results like that are not the norm

 

Was that 300 at the crank that you broke the 9 bolt with? And did you launch it, or just drive around

 

That was 230's whp not quite 300 crank i suppose. That was on a launch at track on drag tires but posi was wearing out, it wouldnt leave as dark a tire mark on one side as it would the other, and i noticed it sometimes didnt spin both at the track initially.

But you can break them on the street from time to time.

 

Great thanks for the tips. I may hold out for an ls1 rear but have a feeling I'll be waiting a long time. I'll probably grab that 9 bolt this weekend though. For 200 bucks I at least gain posi and disc brakes for now. Thanks for answerin my questions

 

just to be clear again, there is no way to tell for sure from a picture if it has the zexel torsen?

 

If the cover is off.

 

Ive had a hard time just finding axles for sale for some reason. Where do you guys find these? Junkyards? They dont pop up in online classifieds often.

Im hoping my 9-bolt lasts a while, but I'd like to have a spare 10-bolt around.

I've actually read somewhere that, somehow I dont understand, the 9-bolts are prone to breaking when the cones wear out. Maybe something to do with the internal spider gears? So if the cones are okay they're probably a good bit tougher... but as hard as it is to get parts for them when mine goes I'm gonna go 10-bolt. I only got it because of the PBRs anyway.

 

As the cones wear the axle gears move farther apart. This causes the gears to run farther out at the face off the teeth instead of closer to the center where they are stronger. This is why they break when they are worn.

 

Thats what happened to me. Was wearing out and i broke a spider gear

 

You can tell by looking. If you can see the opening in the diff case you can see worm gears in the zexel

 

I got a friend who has a gm salvage yard. Gets 4th ten bolts from time to time. Can ship them but its not as cheap that way. Also if you post a want ad on ls1 tech you will get some action. They may not pop up in classifieds by themselves. Part out threads usually have them

 

It's really not that hard to find 9 bolt parts anymore.
Yukon and Motive sell gears, 9bolt.com has posi units, cones, and spider gear sets. Ratech has ring gear bolts, shims, pinion nuts etc. And Autozone has all the bearings.
9bolt.com is kind of pricey, but shipping from Australia isn't cheap.
Hope this helps.

 

Trust me I've been there and done it. My 9-bolt has decent looking cones, so I dont consider it a waste, but after $200 in gears, $150 in shims and pinion spacers and bearings and gear oil and replacement this part and that part and new pinion nuts and gaskets....

Plus the cost of the cones if I needed those replaced... plus I believe new cones require machining to function properly.

That's halfway to a bolt in 9 inch... for a rear end that will still break if you push it. I am a big believer in the 9-bolt being a much stronger axle and a much better design than the 10-bolt, but when you can buy 10-bolt parts from a junkyard for fractions of the cost of 9-bolt parts, and you can buy a 9 inch for a little more than sprucing up a 9-bolt... It hits a point of diminishing returns VERY quickly.

 

I feel ya Vortex, things add up quickly! If i could have found a used Moser 9" I would have probably gone that route. I don't mind putting the bucks into my car, but coming up with large lump sums of cash is a problem on my budget. That's why i rebuilt a 9 bolt. Easier to piece it together.
Same reason I didn't go out and buy a new, Camaro. Besides, it's a great learning experience building a car from the ground up!

 

Thats a raelly good attitude. I can definitely relate to that.