MilitaryIroc

Just curious if anyone thinks it worth rebuilding my 9 bolt. Parts for a 3 series carrier, gears and bearing and seals will run around $1300. I have rear discs and was just going to rebuild it, but are there any other options?

sofakingdom

iTrader: (1)

It should have the PBR (aluminum, 12" rotor) rear discs. If so, it's MUCH more nearly worth spending money on, than otherwise.

As far as "other options", that kinda depends on goals, budget, risk tolerance, etc. How fast are you willing to $$$?

MilitaryIroc

Yah I have the pbr rear calipers. The rear rotors were shot. Just don’t know if it’s worth spending the $1300 and then install around $400. The cost is getting up to almost to be able to buy a new rear end ($2500 give or take)

89GTASC

I had the 9bolt posi unit replaced in my 9bolt 3:27 gear rear axle some 15yrs ago, got the part from australia, not sure if their website still exists or not 9bolt.com I believe it was. But this probably doesn't answer you question, not sure if replacing the posi unit and rebuilt mean the same thing or not, guessing not. Was it worth it? I think so, I like it when the limited slip works. And Liked the 3:27 ratio gear so wanted to keep it the same for me. Anyways that's my 2 cents, I probably spent too much getting that done was between 1000-1500 including labor back in 2005-2010ish.

TTOP350

iTrader: (8)

There's a great torson upgrade to get rid of the factory cone diff. Threads here somewhere about it if you haven't seen it

MilitaryIroc

Yah I’ll have to order from 9bolt from Australia. Also I’m looking at $1300 for parts. I thought about going with the 3.70 gears but I’m not sure. I just got my rear axle powder coated, but debating if it’s worth buying something more updated and in the US. But then again I shouldn’t have to worry about getting it rebuilt again.

rhyno91

What engine and transmission do you have? Are you planning on upping the power in the future? If your engine is making decent power or you plan to upgrade in the future, I would go with a Ford 9 inch, especially if you have a manual transmission. At least that's what I would do if it were me and I was looking at spending that much. YMMV.

MilitaryIroc

To be honest, I’ll probably refresh the 5.7 motor. It was brothers who passed a long time ago and I’m just doing a resto mod from the ground up and then give it back to parents. Although I want reliability for them. It would be different if I was going to do an LS swap. Although I’ll look into a the ford 9” price

rhyno91

In that case you would be fine with the 9 bolt. If you want to go a cheaper route, you can pick up stock used f body rears pretty cheap.

MilitaryIroc

Yah only thing about that is. Can’t find any with disc brakes. Mine came with discs all around

89GTASC

I should share that 9bolt had to send me 2 9bolt "pig" whatever going int the middle of the 9bolt rear axle, becuase the 1st one they sent me was faulty. I had a professional performance shop install it, and there was metal shavings or whatever. But they owned up to it, and shipped me a 2nd one no charge.. Just FYI though, its a rare and old part so I guess your taking your chances... I find the 3:27 gear to be perfect for me. I rode in a 2004 GTO that had a 3:42 and to me and the owner its a bit too much. SO 3:70 what you werre saying, i mean it's all what you are wanting but to me it would be too much... Now w/the 305 w less hp the 3:42 I think is a good match. just my opinion, my 2 cents.

MilitaryIroc

I agree, I’m tasking a risk ordering from them. I’m almost debating about just forking the money and getting a new rear end all together. It’s hard pill to swallow but just be the answer though. I do appreciate the input though.

89GTASC

i'm not real knowledgable about swapping rear ends, so it might be better to do that. in my case i wanted to keep the 3:27 gear and not mess with speedometer gear corrections etc.

MilitaryIroc

I know enough to get myself in trouble and that’s about all. I guess I’ll just work on replacing the front suspension first, and tackle what I’ll do with rear as I get closer

89GTASC

i'm not exactly sure if im glad i replaed the inside pig unit with another 9bolt.. reason why I did it cuz my limited slip wasn't working 100% of the time... like sometimes only 1 wheel would spin.... and I felt like it was becuase of the 9bolt limited slip..... after having it having replaced I sorta noticed that it still sometimes only spins one wheel initially, but then after a second or two then the LSD kicks in and spins both.... but I do feel like it started to spin both more consistently.... then I test drove/bought a 2009 pontiac G8GT which happen to also have 3:27 rear axle and I was surprised when the LSD worked worse on it than my GTA... it made me think maybe it was supposed to work like that lol. needless to say I got disheartened w/that G8GT and returned it. (carmax 5 day satisfaction gaurentee thing).. now lately my LSD seems to be doing good so I'm happy I guess that I had it replaced... there was some break-in period or something. I guess my question is why do you want to rebuild your rear axle, is it not doing something right? if it's performing and doing what you want..then i'd venture to say if it aint broke why fix it?

89GTASC

i'm guessing you have the same 3:27 ratio that I do.. my gut instinct says if for some reason you had to rebuild yours or hunt for a new one, i'd venture to say you'd find a 10bolt 3:23 gear(if you can find it) cheaper than rebuilding the 9bolt... the 9bolt is supposed to be stronger than the 10bolt but prolly not much stronger, like 400hp rating instead of 300hp rating, and if rebuilding one guessing you can make the 10 bolt stronger than the 9bolt. my 2 cents, it's not like i know rear axles very well, just what i needed to know lol.