Posi Woes

[JoeliusZ28]

some of you guys might remember a thread i posted way back when saying i think my posi might be going out. well im about 95% sure shes on her last leg. im pretty sure that my frequent, albeit gentle, sidesteps are an influence on this situation. i had multiple witnesses confirm a one-wheel-wondering tonight

I cant spare an extra washington ( a quarter mind you ) to get it fixed right now, id just like to get an idea of what im looking at here. Can i replace a posi on my own, or is that as involved as a gear swap? Also does anyone know how much the auburn posi's run? (the better one that came in firehawks)

thanks!

[Insomnya3AM]

I do not believe our gear-based Posi's, a Zexel, can be rebuilt. I believe it is the gears wearing out.

Also, you do NOT want an Auburn Posi. They say they are suited for the street and strip, but the bolts WILL back out and it WILL frag. Auburns are suited better to something like offroading where there is a ton of slip. If you hook, it will die. No maybes. I have seen them frag with my own eyes, even in a V6 Stang. My buddies Dad is the head up at Ring and Pinion and he has also said these exact things.

You need something that will give instead of break. An Eaton Posi is your best bet for the street. It is a clutch-based unit, which means that at the end of it's respectable lifespan you can rebuilt it for cheap and rebuild it in a matter of hours.

[JoeliusZ28]

I do not believe our gear-based Posi's, a Zexel, can be rebuilt. I believe it is the gears wearing out.

Also, you do NOT want an Auburn Posi. They say they are suited for the street and strip, but the bolts WILL back out and it WILL frag. Auburns are suited better to something like offroading where there is a ton of slip. If you hook, it will die. No maybes. I have seen them frag with my own eyes, even in a V6 Stang. My buddies Dad is the head up at Ring and Pinion and he has also said these exact things.

You need something that will give instead of break. An Eaton Posi is your best bet for the street. It is a clutch-based unit, which means that at the end of it's respectable lifespan you can rebuilt it for cheap and rebuild it in a matter of hours.

thanks for the info, i wasnt sure if the auburn was the right one or not. but i definitely want one thats capable of handling a few holeshots on street tires

[JoeliusZ28]

on second thought, im debating whether or not i should even mess with this POS ten bolt. perhaps a 12 bolt fund would be the smarter choice. I already learned my lesson not to cheap out in the clutch department.

[Insomnya3AM]

I'd do a Moser 12-bolt with an Eaton Posi. Indestructible.

When it finally does wear out like everything does, you can pull it off the car, swap in new bearings, rebuild the clutch packs in the Posi, bolt it in and have a brand new rear-end all over again. That's all accomplished in a couple hours and about $30.

Just drive your car like a girl (Sorry Ang) for a while so your Zexel doesn't pull a Matt and explode.

EDIT - Did you check your fluid level lately?

[JoeliusZ28]

I'd do a Moser 12-bolt with an Eaton Posi. Indestructible.

When it finally does wear out like everything does, you can pull it off the car, swap in new bearings, rebuild the clutch packs in the Posi, bolt it in and have a brand new rear-end all over again. That's all accomplished in a couple hours and about $30.

Just drive your car like a girl (Sorry Ang) for a while so your Zexel doesn't pull a Matt and explode.

EDIT - Did you check your fluid level lately?

i changed the fluid in it about 6k miles ago, the stain from the old oil spilling is still on the diff cover haha. Yea... i think im just gonna have to restrain myself on the holeshots for a while - probably a good thing anyway

btw, will the zexel really explode? i thought they just slowly became one-wheel-wonders.

[Insomnya3AM]

It's all gear based. The reason why yours is launching one-wheeled is because the clearances inside of it are getting larger. If you beat on it throughout this, eventually the clearances will get to the point where the gears do not even mesh and you won't go forward.

[JoeliusZ28]

It's all gear based. The reason why yours is launching one-wheeled is because the clearances inside of it are getting larger. If you beat on it throughout this, eventually the clearances will get to the point where the gears do not even mesh and you won't go forward.

i wish i undestood howexactly it works, but ill trust you on that.

ive still been getting some rubber out of both tires if i take off straight, but if i gun it making even the slightest right turn, the right rear breaks free and the posi doesnt grab until i let off (i let off right away obviously)

[Insomnya3AM]

Zexel is the company that makes them, it's called a Zexel Torsen Differential.

I could break it down from an engineering standpoint as to how this works, but I think that'd get boring fast.

Basically, it torsen stands for TORque SENsing. Imagine a big mess of high-pitch helical cut gears. When one wheel starts slipping, the multiplied torque is sent to the one wheel with traction. This usually sets the one wheel with traction spinning, so it goes back to the other wheel. This happens so instantaneously that it appears that both wheels are burning out, and they are.

It's a good thing, but once it's life span is finished, the unit must be sent back in to Zexel to be rebuilt. No clutchpacks means no shadetree fixup. It is an incredibly good design and it does offer you better traction than a clutch-based differential would, but for street reliability and ease of maintainence, you can't beat an Eaton Posi.

[1bad83ta]

I don't agree, the eaton is the best posi out there for street/strip application. The gears in the zexel break under larger HP numbers. Believe me mine did twice in one week.

[DETROITMUSCLE]

I don't agree, the eaton is the best posi out there for street/strip application. The gears in the zexel break under larger HP numbers. Believe me mine did twice in one week.

That is exactly what he is saying, so you do agree.

[phoenix_rising]

Yay Eaton!!! Thats the one I wanted. Someone told me to take the rear end off a Z28. which would be better? An Eaton is about $500.

[wezeles]

lol you tell me were to get an eaton to fit an f body for 500 bucks and ill be there in 10 minutes

try more like 1500 for fully assembled...

[phoenix_rising]

I saw it in the Summit Catalogue. Maybe it would not fit???

[DETROITMUSCLE]

Mike (Concept) or one of his friends knows someone who just got a Z28 rear end for dirt cheap, you should look into buying that for a good price it'd be more than enough for your V6 until you really start modding heavily.