Hey Guys, I got on some snow a few weeks ago, one tire on dry pavement, the other on the white stuff. You can guess what happened next... whole lotta tire spin, no go. So I'm faced with the proposition that my traction lock rear is blown, so now I need to think about replacing it...

Options:

1. Rebuild. Great until it blows out again.
2. Eaton. Anyone got one of these? How long does it last before it goes south like the stocker?
3. Power Trax? I know nothing about this one.

Are there other options? I need something that still gives me limited slip, i.e. I don't want a spool type behaving rear axle. I also don't want to drop a ton of skrilla and then have to rebuild/replace it again in 1.5 years, like my stocker.

I don't drive THAT hard, but I guess it was hard enough to kill the original. Ideas?

 

Ford posi units arnt hard or expensive to rebuild. Basicly all you have to do is replace the clutchs. Most people that do it put in 1 or 2 more clutch disks to make it lock harder and faster, yet still retain the posi effect. Usually the replacement clutch packs come with a few more disks anyway.

Unless you're at the track every weekend,thats what I would do.

Andy

 

I had a powertraxx in my 96 chevy and it locked EVERYTIME you wanted it too.Just hit the go pedal and its locked.i dont care if your on ice.The only problem is it makes a clunking,popping noise EVERY time you go around a corner without nailing the throttle.It sounds like something is wrong but its normal.It was cool for me back then but i dont think i would like the popping sound in a new Lightning.Does make it sound like a race truck though.You should see how many people stare at you and think your rearend is gonna blow any second.....

 

Currently there are only two available options, the Eaton limited slip, and the Auburn Street. I'm not a fan of Auburns, and I spoke with them about their unit and tey said it wouldn't handle much more than stock power for long. After having the Eaton in my truck for the past year, it's now on the shop floor (see me other thread for details).

Now, the only problem with rebuilding the stock Ford diff, is that it's no easy job. The diff has to be removed and you MUST have the proper Ford special tools to do it. It's not setup like the 8.8 with the spring in between the gears. But it would still be cheaper to have your dealer do the job than to go with an aftermarket unit.

 

Im no rear end specialist ( LOL) BUT is the example in the first post enough to doom the diff as shot ?

One tire on concrete and one on snow/ice....

This is NOT a locker it is a limited slip diff. My gut tells me that is normal. What I would do to test the diff is line the truck up on a straight empty road and launch as hard as you can... if you leave 2 even length black stripes your diff is still ok...

If the rear walks to one side or leaves a darker longer stripe on one side then there is a problem.

my $0.02

Doug

 

I with Doug on that one.

 

Doug, that's a very good point. A limited slip is not designed to give you equal traction on different surfaces. It's designed to give you equal traction basically in a straight line. So if you are on even pavement, and going straight, the axles should be working as one, and both wheels should get equal torque. But once one wheel has less grip than the other, at a certain torque point, the clutches disengage and power gets transmitted to the path of least resistance, like an open diff. That's where a "locker" type device comes into play. With a locker, you get more power to both wheels, even on uneven surfaces. Most "locker" devices are really just stronger limited slips. Even a Lock Rite, Powertrax, Detriot Locker, etc, will disengage at a certain torque level, it's just a higher torque level. The only "true" lockers are spools and ARB air lockers that physically lock the axles together. The ARB is about the best out there (Auburn and Eaton have electromagnetic lockers coming out), but again, nothing is available for our rear.

 

Well, to lay the other allegations to rest, it also one wheel peels.

Is there nothing like a torsen for the 10.25? That'd rock the hizzouse... I realize that by making 400 RWHP 500 tq, I'm subjecting ANY limited slip sort of setup to a TON of abuse.

I guess I could just get the rebuild done w/ extra clutches. Does the ring gear have to be removed to rebuild it? I thought it didn't, but I'm often mistaken...

 

Wow i stand corrected. I thought our rears were just like the 8.8s.
Seems like every time I start thinking,i get in trouble.

Andy

 

HI!... All LIGHTNING's and F-150's with the 5.4 come with the STERLING 9.75 not the 10.25. I don't have a LIGHTNING but a heavily modded N/A 5.4 and I blew my 9.75 posi. I tore all the clutch pack tabs off. Also the center carrier pin is wobbling a tiny bit. I still get two wheel peel 50% of the time. I'm currently saving up for a new EATON posi.

 

Darn, I had Sal and the Pawn agreeing with me and it didnt help the member.

My info about diff is based on hanging out with crazy guys with 4WD Jeeps. They had lockers that couldnt hardly be driven on the street. Hardly any slip at all at any time. On the right surface off road the Jeeps would plow through a corner cause the inside wheel tried to turn the same as the outside...

The TALON guys have pictures and video of mine doing 1 wheel peel on the autocross and that is normal. I was coming out of a corner the smoking tire was unweighted, yet they all were telling me my diff was shot. A year or more later I pulled 1.8x 60 foot on f1's and a 12.28 on et streets. Its working well enough for me.

Doug

 

Actually EATON bought Auburn Gear out. I live about 30 miles from Auburn,IN where they produce the diff's.

 

OK, so the thing is that I'm going to have to rebuild? Nobody really helped out too much here, apparently I don't have a 10.25 rear? (Although I know for a fact that I do...)

And I thought, much like the 8.8, that I could just pull it and rebuild it myself without specialized tools, but I'm guessing that's not the case?

Grrrrrr....

 

Lightnings came with the 9.75 rear, where'd you get a 10.25?

Dan

 

the 10.25 axle came in 1988-1998 f-250s heavy duty and the light duty. the 10.25 axle is also in the current single wheel not dually, superdutys. i dont know why you would need that big of an axle in a lightning.