1995#263

I assume that everyone thinks that the Torsen Diff is the best? My question is---- What is wrong with using Detroit Lockers on the street? I have read a few comments on them on here in the past. The noise does not really bother me, Hell I can't hear anything over the straigt pipes! Any info would be appreciated.

BTW--my stock Posi gave up at 40k miles!!

Thundrn_Lightning

For now, I think the Torsen is pretty stout. I've got one in my truck. Haven't been to the track yet with it, but it sure does work well on wet, snowy, muddy, and dry asphalt surfaces (yes, my truck gets pretty dirty at times...).

My only beef with Detroit Lockers is that I've heard time and time again that they can be really harsh for the street. What I mean by that is that on wet surfaces, the tail tends to step out a LOT. And the locking and unlocking of the diff that tends to shock to the tires can make the rear step out at times in a corner. While there's no way I'd question their durability or track functionality, that was just a little bit more instability than I wanted for my truck, especially considering that it spends 98% of the time on the street. I also wanted to keep the door open for my wife to run the thing if (and I mean IF) she had to. It's ok for me to catch the thing in a powerslide, but I'd hate for her to have the tail step out on the way to the grocery store.

I've said this once and I'll say this again - ANYTHING is better than that stock differential. Mine was done at 60k miles and again at 75k after a 4-clutch rebuild. Hopefully that Torsen is the last one I'll pop in there...

BTW, I see you're from Hampton. Note that I'm in Williamsburg. You know of any other Lightning fanatics in the area?

Good luck!


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- Kevin
Black '94 #907
14.30@97

lil'Zeus

My stock diff. just went out at 67,000 miles. I had a friend of mine do it at his shop and it run about $800, and then I bought a Trick Flow rearend girdle on top of that!

Everybody this time wanted me to convert to a 9inch...but if it happens again in the future thats probably what I will do.

Shane

Lightning Struck

I'm just wondering how you spent that much on a diff..Did you convert to a Torsen, cuz I know they run about $500 for just the diff..Thanks,

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Curt
'93 Red Lightning #4232
http://www.geocities.com/lightning_struck93/index.html

POWERSTROKE

There's been some good discussions of diff's on forddiesel.com. About 1/2 the active posters use Amsoil in their diffs. Claim they don't need the FMC Friction Modifier. I've livened a Traction-Loc or two up just by adding a bottle of that to the oil. My last F-150 had an "Open" diff when I traded it. I replaced the rear axle seals and when I opened the diff case I found about 4 ears off the fiber plates in the brown stuff that used to be 90W gear oil. When You say yours was "Done" does that mean it doesn't lock up at all?
Biggest problem with Detroit Lockers is the increased tire wear on street driving. Like about double the wear!

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DENNY
'96 F-250 4x4 5-SPD
BRIGHT RED POWERSTROKE
LONG WHEEL BASE LIGHTNING!!!

oilwell1415

The Detroit lockers also have a ton of backlash. The side gears (for lack of a better term, I want to say dog clutches) have a lot of free play that allows the assembly to shift around as you go from coasting to accelerating and vice versa. That's hard on all the parts and doesn't sound very nice. On the newer Detroit "soft" locker this is supposed to be fixed. As previously mentioned, the rear likes to step out. When you turn a corner the outside wheel must turn faster than the inside one. That difference is what unlocks the gears. If the inside wheel starts to spin and gets to the same speed as the outside wheel, the DL thinks you are going straight and locks up again. When it locks up the energy of the spinning inside wheel is transferred to the outside and around it goes. The Powertrax unit uses a similar design, but is supposed to be much smoother on the street. I am going to try one when my bonus check comes in. The Powertrax for the 8.8 is about $425. www.powertrax.com

Thundrn_Lightning

Agreed, you'll end up spending all of 5 bills for a Torsen. That hurts...

Denny,
Defining "done": This is easy - one wheel peel on dry asphalt (very annoying coming off a corner, too). Also, when I opened the thing up, there were numerous ears off of the clutch discs floating in the oil. Doh! I rebuilt the thing the first time and restacked the clutches and spacers to get four clutches per side. I also soaked the friction plates in the old-style modifier for about 2 hours. And, on the 4-clutch rebuild, I didn't use the modifier with the 75W140 synthetic refill. To my understanding, all the modifier does is allow more clutch slip and reduce chatter noise. Now that may have contributed to the reduction of the life on the rebuild, but who knows. When the 4-clutch died, it was the same failure mode.

Couple of other observations. One, part of the reason the clutch ears fall off is because of a sharp edge on the cast iron diff case itself. Look at the base of the clutch ear and you'll most likely see where the sharp corner of the case digs into the ear. That creates a stress riser, and over time we know what happens as a result. Two, while I have done a few 8.8 4-clutch rebuilds on Mustangs successfully, I think in our application the stock-type diff is not up to the task. Here's why: weight, traction, and torque, all of which we have MUCH more of than a measly little Mustang. That just loads and heats up the differential and it just kills it. Add in a spot that creates a stress riser on the clutches, and voila, recipe for disaster. If you can't afford a mega-dollar diff (and I know they're not cheap!), then at least do yourself a favor and radius those corners of the diff case so you don't take off the clutch ears when the clutches burn out again.

Whew. I'm not trying to be the "final word" on this or anything, just sharing my experiences. Setting up a rear is a pain and I hope y'all don't have to go through it a million times.....there are much more fun things to do, like installing nitrous systems, superchargers, etc...

Hope that helps some.



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- Kevin
Black '94 #907
14.30@97

94SVT437

95,
I just got done putting a EATON diff. in my truck about 5k ago. I am really happy with it. It is unbelievable how it locks. At the track it has no problem and it is alright in the ran. It does how ever stay locked when you go around a corner in the rain witha a little gas (does not slide out but you can fell the inner tire skiping).
The best thing of all is that it only coast $379.00. Good luck and keep up updated.

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Justin DiPalma
NLOC # 555
Black 94 #437
14.762 @ 90.71 MPH
14* Timing ASP Pulleys


[This message has been edited by 94SVT437 (edited 01-24-2001).]

Speedy

The Eatons are the way to go.They have oem quality but awesome locking capabilty. They are also rebuildable. Oh affordable too.

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95 Red Lightning
No times
87 Buick Grand National
11.42 at 118 1.65 60ft.

Thundrn_Lightning

Eatons are good, too. It has a plate clutch-style unit with a pretty slick engagement system that works well.

I have this feeling that my brother will be pulling his Auburn Pro sometime soon and finding out firsthand since there is also an Eaton sitting in a box out in the garage. He and I aren't the biggest fans of Auburns.

Later!

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- Kevin
Black '94 #907
14.30@97

Subliminal Message

Kind of ironic, I came on to the bbs to write a letter about my differential. I just bought my truck at 36K, and now i have about 37k and i got stuck in my road today. I adjusted the mirrors to look at the back tires and only the drivers side was spinning. On pure ice at any rpm the other wouldn't lock. I was going to ask about limited slip additive and if it worked, but it sounds to me like differentials are a common problem.
Damon

1995#263

When i say done, I mean the spiders are gone. They have eroded to pratically nothing. The Posi unit still works reasonalby well---ie both tired still light up on dry pavement. The exciter ring is dinged due to the chunks of spider gear floating around. I have no clue why the spiders gave up at 40K but they did. I am jsut going to replace the whole diff as a precautionary step to eliminate doing this again when the clutch ears decide to part company.

Where do you get the Eaton diff unit from?

Litng1

You guys are making me sweat with all this Diffs going out with 40K and such.Ive got 58K miles of hard driving on mine guess I need to start saving.

93blksvtlightning

Marcus,
after seeing these things apart on three different occasions with the same result, I would strongly recommend looking at that rear especially since you are making "the beast"'s engine stronger. Even if all it needs is a simple oil change, look also in the axle tubes for metal shavings and pieces of clutch material - you'll be surprised what gets in there.

I think that the traction locs are just too light for this application. After seeing this, I'd think twice about having one in a stock F150 or Explorer for that matter.

I hope yours is the example of a good one.

BTW, how's your engine project coming along?

Whatever



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-KL
Black 93 #3194

Cruising along at Mach .80...
GM makes me