I am quite happy with my current gearing, 3.08. This car probably sees 70 percent highway. I was wondering what the cheapest way to get Posi would be. I was looking at the SLP Zexel-Torsen unit. I could buy that and have it installed for almost half what I would pay for a Powertrax unit. Is the SLP unit all that I would need to convert and would this work in my 3.08 "peg leg"? Thanks in advance.

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1989 Firebird Formula L03
Stock except for K&N and Flowmasters. Much more to come.

 

I am 99.99% sure that your 3.08 rear has a 2-series carrier. The SLP take-off Zexel-Torsen unit is a 3-series carrier. You would need to get gears made for a 3-series carrier as your current gears would not work with the take-off unit. Still, $99 for an almost new posi unit is a good deal IMHO. I think SLP is running a special right now for $299 that includes the posi unit, gears, a nice diff cover, and a speedo calibration box. I bought one of the posi units a few weeks ago just to have when I do my future gear swap.

 

Another option is Auburns posi units. They are $304 in summit. You need the 28 spline 10bolt one.

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'92 Formula
305 TPI 5speed
1LE package
Mods: SLP headers,SLP catback,SLP air foil,ported plenum,Crane AFPR (42psi),MSD6AL,homemade cold air,K&Ns,3:73s,JET fan switch, Macewen white face gauges...ZZ9 cam (i still have to install it )

 

Ok. What exactly is a carrier? Is that the outside shell or something inside? if it is inside can you change it using the same shell?

pardon my ignorance. Trying to educate myself here.

Bill

 

More or less, the carrier is the actual posi unit you are looking at buying. Basically, the overall height of the two styles of differentials is the same, but the thickness of the thing that the ring gear bolts to is different for 2 vs 3 series... I think.

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1984 z28 w/ a 357 cu in. monster engine which is looking like the posterchild for Edelbrock... all the suspension stuff... 9-bolt posi disk is in... K&N filter... 93 octane...

-=ICON Motorsports=-

 

Right. The part you see from the outside is the same on all 10 bolts. It's the "guts" that are different. You can replace your 2-series internals(carrier) with a 3-series , but you'd have to get new gears. If you want a posi by going to a 3-series, you might as well get 3.42's since you'd have to get new gears anyways. Also, you need to make sure you have 28 spline axles for the $99.00 auburn unit(It's a good unit - they put them in the new camaros and firebirds). 89 was a switch over year for the axles. The only way to tell really is to open the cover and try to count them.

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88 firebird formula
350 Vortec TBI
214int/224exh, .471int/.491exh
Edelbrock headers
SIX-speed
Eats LS1's with a 2.73 open rear and 2 1/4 stock catback

My Formula

 

Just get the powertrax if you want to keep your gears. You won't have to replace the carrier or the gears. You use what you have and add the powertrax. The install doesn't take very long(the carrier and gears don't get removed) and by the time you buy the posi, gears, bearings, and have it installed and set up it will cost more than the slp limited slip and have less traction.


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82 camaro--original steering wheel, brake/gas pedals, seats--everything else modified
82camaro

[This message has been edited by 82camaro (edited November 24, 2000).]