Ok, so I read the article on "beefing up the 7.625 10 bolt" and I'm looking into getting a 4th gen posi unit, because it says they are a direct fit, except for the 28Spline Axles (mine are 26, but I'm perfectly willing to get aftermarket ones or whatever). But all the ads I've seen say they will except only 3.42 gear ratio's and above, mine is the stock 2.73. I have an 87 TA by the way, and it's s limited slip, but I don't think it's working, and I think the clutches are burned out. The only clutches I can find are like, $200!!!! which is the cost of a whole new clutchless-posi!!!! So I guess my question is. 1: if it's the right size (7.5 or 7.625), doesn't it HAVE to work with the 2.73, just as well as the bigger gears? I mean, arn't they the same? 2. I'm I missing a cheaper source of clutch-packs? I simply can't find more than ONE place that sells them, and their some obscure place on the net????!!!! Thanks in Advance!!!!

Stuart

 

First, your '87 TA will have the Auburn differential, which can not be rebuilt. There are no clutches available for it because it doesn't have replacable clutches. When it wears out you take the whole thing out and toss it in the trash. Then you clean all of the powdered metal sludge out of the axle tubes and housnig before putting something else in it.

The 7.5 rear end uses a 2 series differential for 3.08 to 2.41 gears and a 3 series differential for 3.23 to 4.10 gears. If you have a 2.73 gear then you are going to need a 2 series differential or change your gears.

If you find a 4th gen Auburn then pass on it. In no time it will be worn out too, if it isn't already. If you find a 4th gen Torsen then it will probably be all right. If you want to put in something that you don't have to worry about then get a new Eaton Posi.

 

Ok, thanks for the help! So, what your saying, is since the 4th gen Torsen's seem to only come in 3.42ish or higher (or am I wrong on that?), my only option is change the gear ratio's, or go with a eaton? Can I get a part # or whatever for what is going to be a stock replacement? or what I can upgrade to 28 spline with (if I get the axles of course) Oh, by the way, I'm running a 400SBC cranking about 450-475Ft.Pounds of Torque, with a 700r4, and fairly sticky wide-ish mickey thompson indy profile tires. If that factors in to anybody's recommendations. Thanks.

 

"Oh, by the way, I'm running a 400SBC cranking about 450-475Ft.Pounds of Torque, with a 700r4, and fairly sticky wide-ish mickey thompson indy profile tires. If that factors in to anybody's recommendations."

Yea, that factors in. I recommend that you get a stronger rear end and don't spend more money on one that's probably going to break soon.

As far as I know Eaton only makes a 3 series posi for the 7.5, so that leaves them out if you want to keep the 2.73 gears. Your only option is going to be a new Auburn, which is sad. If you change the gears then you are open to many more options.

 

What about a Detroit TruTrac? like this one? http://cgi.ebay.com/ebaymotors/ws/eB...=STRK:MEWAX:IT

 

That would work. The Truetrac is better for auto cross than for drag racing, but it will work.

 

My objection to changing my gears, is I'm already finding it IMPOSSIBLE to hold traction in first gear as it is, that 400 just makes a cloud of smoke, ALL the way through first gear, the tire(s) don't quit spinning until right before it shifts into second. It really isn't any fun that way. I'm going to find out (as soon as it's dry, and can get someone to watch from outside the car) for sure if my posi is actually bad, because I'm sure THAT will have a large effect on traction (duh). I also don't have my MT's yet, I'm currently running wide-ish generic all-weather tires from Les Shwab, and nice though they may be, they are NOT up to high power apps. I'm just REALLY frustrated, I mean, is it common to have traction be a HUGE issue like this? I mean, I know I'm not running drag slicks, but I'm also not running a 1200HP BB or whatever!

 

I'm not drag racing, it's a daily driver, But I don't want to flinch everytime I step on it and go "please don't blow up..." in my head every time. I also just want it to HOOK UP DANGIT when I DO step on it. not just make a cloud (I'm not holding my breaks or anything, just flooring it, at anything under 30MPH, it just smokes, and smokes, until EVENTUALLY they catch)

The thing is, I have NO desire to go FAST it's the getting up to the speed limit as fast as possible that's the fun part . and my lack of traction is taking all the fun out of it. I can only accelerate fast if I'm already GOING 30MPH or so. Basically, I'm after the "Holy Crap" neck snapping effect of a great launch in first gear. I know that technically I'd be getting MORE torque gonig to "lower" gears (3.23 etc...) but It's already a high-torque, not high-reving engine, so it tops out pretty quick as it is, and making MORE smoke doesn't really appeal to me . Thanks for all the help!

Stuart

 

The thirdgens are notorious for being "traction limited" even with stock motors..... Might want to dip into the suspension boards for some tips/tricks on making the car hook better with what you have.

Making sure your posi is actually doing something is a good starting point.

 

I've never dug into the suspension stuff, are there any basic mods that are accepted as worth it? I'm not willing to spend ALOT of time on this (well, within reason ).

Stuart