Ok, I planned on odering a Powertrax Locker today, but I ran into a little problem; I don't know what rear is in this car. I know its a 7.5 or a 7.625, but I'm not sure. I put my RPO #s into the decoder and the only thing it said about the rear was that I had 3.08 gears. It said nothing about the ring gear size or the axle spline #s. Is there any way to find out without taking the cover off the rear and counting axle teeth? My guess is I have the 26 spline axles (assuming they're the more common ones), in the 7.5 inch rear (assuming I remember correctly). Sorry for the stupid questions, but I was never really big into F-bodies until I bought one, now I'm trying to learn as much as I can. Thanks in advance.

 

You have to many unaswered questions to be ordering parts for a rear axle. I suggest a little more reseach before putting a locking diff in the rear.

 

I'm not an expert on the thirdgen rear ends, but there was a changeover year (I THINK it was '88 or '89, but I'm not sure) when they started putting the 28 spline axles in instead of the 26 spline. That being the case I'm pretty sure you have the 28 spline axles. Do some searches through the boards and you should be able to find conclusive answers to most of your questions, I'm really not sure on the 7.5 vs. 7.625 inch thing myself, and that's a question I'll have to answer before I order my Powertrax unit (somewhere down the road ) Anyway, sorry I can't be more help, but like I said, you should be able to find a lot of answers to your questions by searching the boards! Good luck!

-Paul

 

I am not sure what you have, sorry can't help. Do a seach and I am sure you can find out what you need. Those changeover years and different sizes don't help either.

 

What are you saying? That post doesn't make sense. I was trying to help the guy out a little. Sorry if that bothered you.

-Paul

Edit: Going by his screen name I was asuming that his car was a '92 and thus would have the 28 spline axles

 

If you have a 92 firebird, you probably have the 28 spline axles since the change over year was in 89. I have a 5 spd 91 camaro and I ordered the Powertrax No-Slip unit with the 28 spline axles from Jeg's part# 754-92-0776-2805 which only comes in one ring gear size 7.625 and it fit perfectly.

 

To support what GKK said I just did a quick search through the boards and '89 was the changeover year for the axles, so basically '90 and up 3rd gens should have 28 spline axles. Also, 7.5 and 7.625 ring gear sizes are the same thing. From what I read GM just decided to change how they denoted the ring gear size, but there is nothing different between the 7.5 and 7.625 ring gears, according to the information I found. Good luck!

-Paul

 

Ditto
S-D

 

Just make sure the rearend hasn't been swapped out for an older one somewhere in its past.

 

no, the car is all original, i have all the records from the original owner i bought it from. i ordered the locker today. i can't wait till it comes in.

 

thats a bad *** part man....it takes some getting used to, but you'll love it

 

ok, guys with the powertrax, what kind of fluid do you have in the rear? do you need a posi additive?

 

just regular 80w90....it doesnt have clutches so it doesnt need additive

 

So what is a powertrax locker? What makes it more badass than limited slip/positraction?

 

i may be wrong about this, but from what i understand it stays locked under most driving conditions(but not turning)almost acting like a spool, where a posi will only put power to both wheels when one starts slipping. once again, that's my understanding about it, i could be horribly wrong.

 

think if it as a posi with teeth and ratchets instead of clutches....

when your going straight, the wheels are always locked together.....this is true in a positraction differential as well.

if one wheel starts to spin at a faster speed (turning) it will unlock the axle from the driveline (locker) or release the clutches allowing the axle to rotate freely (posi)

and yes, its way tougher than a posi is

its lasts alot longer because there are not clutches to wear out, and it gives you all the benefits of a spool at the track without actually having one

 

This is a good thing. I will look into this in the future when I do the "daniel burk 7.5" beef up"

Thanks!

 

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read what you quoted AGAIN.

He said it has the benefits of positraction but it is less complex so it is tougher to break. From that you can assume the powertrax is superior to limited slip.

 

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For you, I would forget about rear axle work and just work on your engine for starters. One project at a time.

 

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I have a Powertrax in my Dodge Ram and in a straight line there is no doubt that the Powertrax is Awesome. Although, around corners the Powertrax manners could use some refinement. The Powertrax disconnects the outside wheel around a corner, making the inside wheel slip very easily due all engine power being received. What's even more weird is that the wheel on the inside will not spin up like an open diff, it just hopps as the Powertrax engauges and disengauges. Another attribute is that thier is alot more drive train slop as you come on and off of the throttle, especially with a manual. This might not bother some but I find it frustrating and I wonder if the slop is hard on my differential case? Just thought you might like to know.

 

I have the Powertrax No-Slip unit in my 5spd 91 Camaro and I have no drivetrain slop at all. Driving around corners I push in the clutch lightly or coast around the turn and the Powertrax unit engages and disengages smoothly.

 

its not the smoothest thing on the planet for sure.....but how it behaves has alot to do with how the rear is setup.....if the gears arent setup perfect, or the carrier isnt perfectly centered or anything is misaligned.....that unit will makeit more apparent....

it also doesnt have any more slop to it....but it sure will make you notice any slop that was there before alot more quickly.

the fun thing with the locker though, is going around a corner and nailing the throttle....because when power is applied it will automatically lock both axles in and give you a nice slide.

 

Me want.

 

How can it not have any more slop! The instructions state that thier is more slop/play after installation and if you look at the assembly out of the box it is pretty obvious where the slop is coming from. The cross shaft is allowed to move inside the drivers to activate the syncros. Maybe it's because I have a 5300lb truck with leaf springs vs. a 3000lb Camaro with coil springs.

 

I have one in the '57. Since its main duty is straight-line 1320's, it's fantastic for that. I do drive it to the track, though, and since I used the heavier track springs, I don't even power it around corners.

I ran it for a year, took the rear apart to get the 3.73's installed (the shop didn't want to mess with the PowerTrax), and the thing looked brand new still. It did seem quieter after I put it in the 2nd time, for some reason.

 

I loved mine. I had it for over 3 years in my Camaro before swapping the rear out. I saved the Powertrax and junked the rear. It's literally in like new condition. After cleaning it the wear marks are almost invisible. It's going in my S10. The Torsen I have now is better behaved, especially on twisty roads and parking lots, but in wet weather the locker performed noticably better than my Torsen.

 

well, i got the locker last night, and the weather said snow today(and we sure got some snow), so we decided to try and put it in last night. well that didn't work, the coupler was .003" bigger than the original gear and would not fir into the hole on the driver's side inside the ring gear. needless to say, i was a little annoyed, not only because we spent a total of 1.5 hours taking the rear apart, and trying to fit this thing in, but also because i got stuck twice in the snow today. all you guys w/ 92s or the 7.625" w/ 28 spline axles, what part number did you order? i got part # 9207762805, it said 7.625" 28 spline axle. does it matter i have 3.08 gears and therefore the smaller carrier? is there a seperate unit for this? i'm still waiting on a responce from someone at richmond to see what's going on, but i was hoping maybe someone here knew. thanks in advance.

 

I ordered part #754-92-0776-2805 from Jeg's for a 91 Camaro with the 5spd, 3.08 gears with 28 spline axles and the first unit was shipped with the correct part # on the box but had 26 splines.

It just sounds like the wrong unit was packaged in the box with the part # you ordered.

 

it fit my axles fine, i'm hoping it was the wrong unit or somthing like that, my other guess was the tolerance was off a little. apparently it seems to be a common problem with them, my friend had to send back 3 untis before they sent him the right one for his camaro.