No one (except Borg Warner in Aus) makes any gear sets for the 9 bolt except the one Chinese 3.70 gear set that is rebranded by everyone. I bought mine as a Yukon but I'm 100% sure it's the same as the Motive and several others. Get a 3 series Torsen carrier from Australia and you'll be set. That's what I did.

GD

 

 

No, it is 3 series. Which is why you buy a 3 series carrier to go with it.

 

 

No you get a new 3 series Torsen carrier. Here's my post on the subject:

https://www.thirdgen.org/forums/tran...rg-warner.html

Unfortunately my experience with 9bolt.com was terrible. He stopped replying to my emails. I threw away a lot of money on his "rebuilt" carrier and it was junk.

GD

 

 

Recently? I thought I read here that someone bought the domain and site and was selling stuff, but the previous owner disappeared

 

Yeah fairly recent. About 1.5 to 2 years ago I guess. It was after the acquisition - I read about that. The unromantic truth is that you can't rebuild these carriers and to try is foolish. Especially since for the same relative price you can get a Torsen that is 1000x better.

GD

 

On another note, not saying it would make a huge difference from the 2.77 but I also found that the '89 9 bolts came with 3.08 as an upgraded option, but can't find those gears to fit the 2 position carrier either.

 

Correct, but all the stock carriers are junk anyway. If they aren't worn out they soon will be and they are 100% non-rebuildable so the only way forward really is to junk the whole 9 bolt rear end or find a better carrier option. We have done that with the Holden Commodore VL carrier that is a perfect fit. You will still spend $1000 by the time you by it, the gears, and all the rebuild parts. And even more if you intend to do it yourself and need the tools like the pinion depth and special torque wrench to set the preload. But it's still a stronger option than a 10 bolt, and much cheaper than a 9" or a 12 bolt, etc which will cost about $2500+ with shipping, etc.

GD

 

Thanks again GD for helping me understand all of that!

 

You think that is true? I have a 9 bolt in my car that broke, haven't opened it yet to know what broke though. Car still rolls, so I am THINKING spider gears? I have been eyeing that torsen style carrier and I am wondering whether I should bother spending the money on it. I have a STOCK 4.8, T56 and the 3.45 gears and hard as a rock tires.

 

Actually the Borg Warner differential in the 9 bolt can usually be reconditioned once. It requires a little work on a lathe and some shimming, but they work pretty well for a while after this. They will eventually wear out again. It's the same basic differential that was used in the '64 to '72 GTO, and people, including me, have been rebuilding them for many years. The Auburn can not be rebuilt, but the Borg Warner can, once.

 

Perhaps your skills are better than Glenn at 9bolt.com. His rebuild immediately made tons of metal - oil looked like silver paint - and it creaked and popped like crazy when warmed up. Worthless in my opinion. The Torsen didn't even cost much more.

GD

 

The Torsen on the 9 bolt would work fine for you. The 4.8 has about the same torque as an L98, with only a little more HP. The 9 bolt has 28 spline axles and a larger R&P than the 10 bolt, and overall a heavier duty construction. With the torsen carrier there is no spider gears. The Australian guys are putting 500+ HP through them routinely.

GD

 

I "reconditioned" my carrier too, it wasn't hard. I just ground the end of the cones off and the lip inside the carrier until it was flat, shimmed the spider/cone interface and I didn't even have any issue like you're describing. I don't know about the metal in the oil as I glued a hard drive magnet inside the bottom of my housing to try to keep the flake out of suspension, if possible. I didn't even use any friction modifier in mine and it didn't make any popping noises.

OK, I think I will give it one more shot then since I have no plans on getting more power out of the 4.8

Are the spiders the common failure in the stock 9 bolt then? I have the girdle from TA Performance, so I am guessing the spider gears let go, unless I broke an axle or gear teeth, but I think that is unlikely. I was not under a lot of power, I heard a pop, car bucked slightly, I let off, pop again, let off, then gave it a little throttle and it was like the engine was freewheeling. Had a colleague help me later check. When he let up on the clutch the DS spins freely, but car no move. There were no other bad noises than the two low pops, no grinding or crunching like I would think you would get from broken teeth.

 

Mine wasn't broken when I pulled it apart but it is certainly possible to break the spiders, or even the carrier itself maybe. Doubt you would have broken an axle... I'm curious - how long did it last after reconditioning? Mine from 9Bolt.com was terrible - made so much slurry and bad noises (with additive - several different types - and the Amsoil gear oil has it in it already), that I got the Torsen and swapped it out after only 6 months. It wasn't even really working as a limited slip. I couldn't break them loose easily with it like the Torsen. With the Torsen carrier I'm sideways from every stop and it never makes any noises or metal.

I really think you would be happy with the Torsen and my upgraded LB9 makes probably near the same torque as your 4.8. I also have a 700R4 race trans with a 3k converter that shifts so hard it goes sideways into second. So I'm putting plenty of shock loading on it and no problems. I have the TA rear cover also.

GD

 

I got a little over a year out of it and around 11k miles, plus one track event after reconditioning. The track event was 2 days, one of auto cross, and a 140 mile cruise, day two was speed-stop and 3 sessions of the road course getting to around 120mph at the end of the front straight. I must have done the speed stop 25-30 times. I also beat on the car every chance I get.

Although there may be extenuating circumstances with mine breaking. My LH axle leaks out of the end of the tube, so I think the oil is low and has been for some time, but I took an off ramp and sustained the high G, when I got home I could smell gear oil. It puked a bunch on the ramp, so I was even lower level after that. I was going to pull the axle soon to try to fix the leak, but this happened first, lol. I know the TA cover increases the oil capacity slightly, so I think before the initial puke there was still enough oil, but the second one may have done it in

I have another stock 9 bolt I am borrowing to get me back on the road, I will open mine after and see what the damage is, the amount of flake on the magnet. I had changed the oil after about 5,000 miles and it looked good, so either there isn't a lot of wear in that time, or the magnet is really doing it job well. I had planned on doing the oil every 5k miles since they shed so much. When I initially pulled it apart, it was like yours, metal soup and the cones had galled the carrier pretty good since the oil couldn't do it's job. I was hoping the frequent changes would prevent the buildup inside the hard parts and get me a good amount of life. I figured the ~$30 gear oil at my engine oil change was worth the effort and cost, especially since it is easy to change with the TA cover and I have a hand pump on a bottle, wasn't a lot more effort than the engine.

 

I can imagine that running it low on oil is worse for the spiders than it is for the R&P just based on their height above the sump.

I had a tube seal fail shortly after my Torsen swap - it was original (I hadn't done the wheel bearings at the same time) and probably the metal slurry from the cone diff damaged it as well. Fortunately it was just streaming down the tire a bit and hadn't leaked any real quantity so I haven't run low.

I did notice on the TA cover you need to seal the threads for the carrier bearing cap reinforcing studs. Otherwise they weep gear oil.

GD

 

I don't think I have noticed any oil leaking there, I may have put stuff on the threads and forgot though