NCcowboy

iTrader: (2)

Managed to find what turned out to be a 2000 Firebird Formula in the U-pull it yard down the road from me and have pulled some parts from it, including the rear end that the GM dealer has confirmed is 3.23 gears with Posi. so I was ecstatic to be able to go pull it and pick it up for $80. with the brake components and all. My question though, this one has the rear wheel speed sensor for w/o traction control, that bolts onto the top center of the housing. Has anyone else encountered this, and if so did y'all plug the hole somehow or just unplug the sensor and leave it disconnected? I do plan on cleaning, painting, and replacing the brake hoses. As far as the gear oil, I was going to use Mobil 1 75-90 and lube guards limited slip additive. Anyone have any bad results from either of these? thanks for the input as always!

BuiltZ28

Is it a true clutch type posh or a torsen. If torsen there is varying opinions on whether to use the additive or not.

NCcowboy

iTrader: (2)

I'm not 100% sure, I plan on opening the case tonight to find out.

sofakingdom

iTrader: (1)

Why didn't you take a look for yourself while he had the cover off?

Yes you can just plug the sensor hole. No unfortunately I don't know the thread size offhand.

Yes that fluid combo may be OK. I guess that depends on what you saw when the GM dealer pulled the cover off to verify its contents. Tell us what it looked like.

If it's a Torsen it doesn't need additive. If it's an Auburn it does, for what little difference it will make, if it still works at all; it's probably already wore out.

BuiltZ28

guessing he ran the numbers to the dealer not brought the diff there

sofakingdom

iTrader: (1)

Oh that... total waste of time money and effort IMO... I thought I read somewhere he said something about "confirmed" as opposed to a bunch of THAT crap. Maybe I misinterpreted the word?

I guess my idea of "confirm" (LOOK AT THE PARTS and see what they are) is different from "guess what they might still be based on some numbers I found written on something somewhere that might or might not maybe be related to what the assembly or the car came with but who knows whether it was associated with the car or whether anybody has ever changed anything about it".

My 83 car still has its weenie stock gear ratio (3.73) except in a 90-ish housing (that DID NOT come with that ratio) with an Eaton posi and PBR brakes on it. Run the numbers on THAT and see what "the GM dealer" comes back with. Granted, not EVERY junk rear you come across has such an active history; but there's A WORLD of difference between "run the numbers" and "verify", no matter what.

NCcowboy

iTrader: (2)

Sorry, guess I should have clarified. Yes, I called the dealership gave them the vin and had them tell me what the axle from the factory was. As far as opening it, I was going to get into it tonight, but didnt because i test fitted my wheels and they don't have the clearance to bolt on, so I'm scrabbling to find something relatively cheap to get me by on for the moment. I don't want to get into it too much time and money wise without knowing I'm going to use the axle.

NCcowboy

iTrader: (2)

NCcowboy

iTrader: (2)

Ok, opened it up and cleaned it up, had a little bit of material on the magnet, not a lot. Fluid was not burnt and the teeth on the ring gear looked good. Anyone see anything that doesn't look right? Tried taking pictures of the stamping numbers I could find

sofakingdom

iTrader: (1)

It is a torsen. The gear is 13:42, i.e. 42÷13, which is 3.23. Meaning, it evidently still matches whatever was looked up. Sometimes you get lucky that way.

Being a torsen, it doesn't need additive. Use Mobil1 75W-90.

If the pinion or axles seals aren't leaking you should be good to go.

big gear head

I'll second that, no additive needed. The additive is only for clutch type differentials, like the Eaton Posi, Auburn, Yukon Dura Grip ....

Jorlain

iTrader: (4)

Huh. Learn something new every day. I thought the rears with Torsens only came with 3:42s.

BuiltZ28

M6 cars came with 3.42, I have a low mileage gm 3.42 ring and pinion out of 02 ws6 if your interested.

I think your better off in that situation being a junkyard rear end that it's a torsen. They either work or they don't. Spin the pinion only one axle should turn.

NCcowboy

iTrader: (2)

Thanks for the input guys, yes, I spin the pinion and only the drivers moves, with some slight movement (not much) from the passenger side. I cleaned the gears and assembly the best I could and filled with the Mobil 75-90. All the seals seem fine. No tears visibly but will keep an eye out.but for 90 bucks (including the $10 core) I got the axle and all the brake stuff attached to the axle. I think i did alright lol

BuiltZ28

Thats a steal

Ty92Z

iTrader: (11)

Where in eastern NC are you? I’m in the Fayetteville area. Nice score, you did well for yourself! I just picked up a 3.42 SLP complete rear for $120! I’m transferring the guts to my 3rd gen housing to keep my stock width.

NCcowboy

iTrader: (2)

I'm in New Bern, I've actually spent so time in Fayetteville in college there, and use to hang out with Camaro South club there.

big gear head

Be sure to do a pattern check (take pictures of the drive and coast pattern) and measure the backlash before you disassemble the 4th gen rear end so that you will know how to set it up when you put it in the 3rd gen housing. If you don't then you will have no idea where to set the pinion depth and backlash when you put it back together.

Ty92Z

iTrader: (11)

Thank you sir for the advice and the previous advice given concerning bearing and shim kits. I’ll admit that I’m putting this in the hands of someone who has many years of experience. This is one of those times where I rather spend the money and know it’s right.

NCcowboy

iTrader: (2)

So for anyone else that has done this swap, I also got the Founders LCA and relocation bracket, I'm trying to bolt everything up but for some reason am struggling to get the E-brake cable/brake line bracket that use to mount at the axle with the LCA to bolt up. Any pointers or helpful notes? Will the stock 4th gen bracket not work any more?

//<86TA>\\

iTrader: (14)

You have to cut the e brake bracket since the width of the mount is wrong once you add the relocation bracket.