Xophertony

buying 4th gen rear end.
out of 94 camaro. posi/disc/ 3.23


here is what i want to do:
put the posi unit in my 3rd gen rear, and keep my 3.42 ratio (keep current gears) is this feasable?

eventualy, put 4th gen discs from this rear onto my 3rd gen drum rear. (i know this can be done.) are the drum backing plates wealded on to our axles? are the disc brake backing plates wealded to 4th gen axles? i know on other cars i have worked on they were wealded, but last time i did a drum brake job on the birdie i could swear i saw like rivets or somthing. any ideas?

the main reason i am not swqapping out the entire rear is astetics mostly. i don't want my wheels sticking realy far out, i also do not want aftermarket wheels (with diff. offset to compensate for new rear) i love the look of stock wheels.

can anyone help me

V6sucker

feasible? Yes. But to be honest, it would be cheaper and easier to get a set of 4th gen rims and front wheel spacers to fit the 4th gen front rims.

Xophertony

yeah, but 4th gen rims are ugly as hell. and the rear end is going to cost me 250-350.

Project: 85 2.8 bird

save your $$$ and get a posi unit specifically for your rear.


how many spilines are your axles? how nay in the 4th gen?

what type carrier is your? what type carrier is the 4th gen?


the answers to these two questions will let you know of the feasability of your swap.

Xophertony

i don't supose all 2.8s have the same spline count?

where do you get a posi unit? summit does not seem to carry them, jeggs has a bunch, but i don't realy understand what i am looking at.. *** i hate not knowing all this stuff. i don't supose theres like a "the brand" when it comes to these things is there?

the ones for our cars seem to be about $400.

2_point8_boy

$400 is about right for a quality posi unit. I like Auburn myself and will eventually put one in my car. All 2.8's have the same carrier and spiders, and therefore spline count. The thing that you really have to worry about is the spline count on the 4th gen rears.

eric17422001

Fourth gen rear will be 28 spline, So in order to use that posi (limited slip) carrier in your housing with your 3:42 gears you'll need to buy/find a set of third gen '91-'92 28 spline axles.

V6#22

You guys have hit the nail on the head with your answers.

Your current 3rdgen carrier and axles are 26 spline. The 4th gen will be 28slpines. The carriers will not swap.

I favor Auburn "roadrace version" posi's. Its what I am currently running and they have stiffer spring rates than the standard versions Auburn posi carriers.

You can use the 28 spline carrier in the 3rd gen rear if you change your axles. Moser sells alloy drilled flange axles new delivered to your doorstep for $300 pair. I am running Moser drilled 26splines though, no need for 28's on a low HP V6 that will never see more than 250rwhp on a good day. Besides, 26mm is less unsprung and less rotation weight for both better handling and less hp loss through the drivetrain.

Xophertony

if i was sticking with a low horsepower application i would definatly not spend 300 on axles and 250 for the 4th gen rear. i would save 150 and just buy a brand new posi. however "no need for 28's on a low HP V6 that will never see more than 250rwhp"...

what if it will see 250 hp and 340 PF of torque? would 26 splines not be enough to handle this power? i never realised a rearend could just break (except from off-roading )

and before anyone asks, let me just say that no i don't expect to get that kind of power out of a 2.8. i expect to get it out of a 3.8

thanks for the help everyone.

eric17422001

I think that stock 28 spline axles would work fine for your application- I've seen 26 splines hold up with more power and abuse than you'll throw at it.

Check the board classifieds, axles come up from time to time.

V6#22

Just for the record, a decent average quality new posi is going to cost you $400 (not installed, thats if you setup the backlash yourself and know what you are doing). A very good posi is going to start at about $550 and go up from there. Just know you get what you pay for. At minimum, I recommend the RR version Auburn. I do not like the normal Auburns, nor do I like the Eatons. I have a detroit locker in my truck with a 9" for heavy duty use and the Vette has a Goldtrac racing unit in it.

Xophertony

would an Auburn be better than stock?
should i buy the 4th gen unit and just hunt down 28 splines?
do i realy need a great posi unit? i am not crawling over rocks or drifting, just looking for more fun on the street.

i am not looking to put this daily driver where deans "daily driver" is, that thing is a little nuts...

V6#22

Every car and truck I own is a little nuts with the exclusion of my '77 ElCamino. Its a cruiser, its a boat. I keep it as a backup worktruck in case mine goes down for a few days. I drive nothing stock- I can't stand pulling up to a stop light next to something someone else drove off a sales lot thats indentical except maybe rims- oohh boy, rims [Driving around So Cal is like-this light, Suburban with Foose rims, next light, Chrysler 300 with Boyd rims, next light Tahoe with Dubs- the common factor, they all spend thousands on rims but put them on $20 tires just so the car "looks cool"]

A decent posi that will work for daily commuting especially in wet wheather traction is a standard Eaton or Auburn. I don't know about these SLP takeoff units everyone buys- they are cheap for a reason and they have been taken off for a reason. I have burned up a standard version Auburn in my V6 from hard cornering hence why I went to the RR version- it has heavier springs so the cone clutches don't slip as much under force.

I would never buy anything used and use it- buy new or 95% of the time you will live to regret it.

Xophertony

by RR version do you mean the high performance one? that was th eone i was looking at getting.

however, on a slightly different subject, the project this was for is probably not going to happen. after pricing it out, including estimaded oops budget, this swap is going to cost 10 grand (the guys at turbobuick.com told it would be that much, but i had to see for myself ) so i think sometime in the spring i will be on the hunt for a higher mialage TTA. start building that...

i would rather spend the ten grand on 1 of 1555 then on somthing that can be called a hack job. plus the TTA (if taken care of) will atleast hold it's value. if i do all this work to my birdie then sell it i will bee lucky to get half the value out of it...

TransAmMike

Sorry to get a little off topic, but I've been thinking about converting my rear end to posi if it isn't too much work. For one that fits my year/model, will all I have to do is buy the differential unit and swap it in?

Project: 85 2.8 bird

why not start w/an L67 long/short block? parts are cheaper

I have it on good authority that the block will fit

Xophertony

whats an l67?

Project: 85 2.8 bird

it's the SUpercharged 3800 II in the GTP's. Might even look into teh "new" L32, The Supercharged 3800 III in the current generation GTP

V6#22

no, The *High Performance Series* is the standard Auburn unit. The *Pro Series*is the RR or roadrace version I am speaking of. I bought mine a few years back from Tom's rearends near me in Downey. I hear he is no longer there though- business moved? His website is dated 2003 still so the prices still listed might not be valid anymore. But he at that time had the best prices around. All the local racers would go to him.

The Proseries carrier for 26 spline axles and 3.23/up gears is Auburn # 542044 (Toms is listed as #7.5-AP3-PS $368.00)

The standard high perf series is Auburn # 542057 (Toms listed as #7.5-AP3 $305.00)
http://www.tomsdifferentials.com/cat38.htm

I strongly agree that hunting for a TTA is a very good investment. You willnot loose money buying one at a reasonable price. Any car is a money pit and a loosing propsition, so anytime you can buy a car and in 10 years get every penny back you first paid for it is a winning deal- A *decent* priced TTA is such an example.

PS- you do not want a detroit locker on a lighteweight car like these for any kind of daily street driving or even roadracing. They are more for light street driving and drag racing. They are very noisy and can click in violently when driving the car mildly- they pretty much need to be hammered all the time with hard driving,not a smooth engagement. Plus the inner rear wheel will slip and chirp around every little tight corner at low speeds

V6#22

Nope, not that easy. The carrier holds the ring gear and a new carrier will have to be shimmed properly so the gear mesh (backlash) is set at proper depth on the teeth. All carriers can and usually are different shimming. If this is not set correctly, you will have noise coming from the rearend and premature life failure of the componants- you need to know what you are doing.

The gears are marked with putty and spun forward then back to check backlash depth then reshimed and so on until correct shimming is done.

Xophertony

i am sorry i misread the auburn page. i was looking at the roadrace version before. that is the one i would get (however if i am going to be getting a TTA my 2.8 will just be my winter bird) so that would or wouldnot be a good diff for low traction situations like wet/snowy ground? and would or wouldnot be a good differential for normal/extreme on road driving?

more then likly if i get a TTA i will take its stock posi unti and axles and put them in my 2.8, then upgrade the axles and diff in the TTA hell yeh

drdave88

iTrader: (3)

heres what i did, i bought an SLP take off ( zexel torsen posi taken out of a 4th gen, mine was out of an 01 camaro) and bought 90-92 28 spline axle shafts and plopped it all right into my current axle housing. its a beautiful thing, and for $300, minus labor, a friend did it for $50. if you can set a rear end, its gravy. you dont need to do anything other than 28 splines for a 4th gen posi. just make sure theyre 3rd gen shafts, the 4th gen are longer. if you wanna go 4th gen discs, then i think youll need to swap the whole axle housing, but im not sure, im gonna stick w/ the drums.............. for now.

Xophertony

i could always go thirdgen discs....