I have a $99 SLP take off diff in a Camaro and have a question.

When I jacked it up today to change gear oil, I spun the tires in neutral to make sure brakes were not dragging. The tires spun in same direction all of the time. There was no differential action, i.e. tires turning in opposite directions. I tried also in park too. The only way to get tires to move independantly was to push in opposite directions with two people. I went ahead and pulled girdle cover to check condidtions. There is no idication of any bearing or axle problem. Pinion bearings are good and backlash is fine. Car is drag only w/3500 stall converter and slicks.

Is this normal or an early indication that Diff is going bad?

 

I believe you have to put resistance on one wheel then turn the other. The Torsens work differently from what I've read.

 

Edit: XXXXX operation with a Torsen. Do make sure that you run Synthetic oil with a Torsen.

Edit: Re-reading your post. Something may be starting to go. With both wheels in the air and transmission in neutral, a Torsen will normally rotate wheels in opposite direction when one wheel is rotated by hand.

 

hows the take-off posi holding up? I need posi and I have been thinking about getting a slp unit. (well I had one but sold it thinking I was gonna get a eaton).

How much power of the 99$ slp take-offs good for?

 

They're OK for street use. You absolutely MUST use synthetic gear oil if you wnat them to last for any amount of time.

They will fail from excessive wear if used for Autocross or Road Racing use. The components inside simply cannot be made large enough to handle the axial and radial loads placed on them. The ring gear is too small. The carrier has to fit inside the ring gear and that means that everything inside the carrier has to be made smaller.

Once the ring gear size gets to about 8.5", the internal compenents can be made strong enough that you don't have a problem. That's why Mustang owner don't have the wear problem that we have.

Talked to Zexel Torsen Tech some years ago about this problem about three years ago when my T2-HD failed after three seasons and they explianed in detail the issues. Usually the cross shafts will enlongate the holes in the carrier, that causes the worm gears to move away from the spur gears. Shortly thereafter the whole thing will go ....KABLOOEY ( To use a technical term ).

Zexel was surprised that I got 3 years out of the unit when they heard the details and use of my car. Another Hunter Motorsorts Team member only got about 3 months out of his before he blew it up.....but he was a bit of an animal. Note that we were using the HD unit, not the OEM SLP take-off units. The HD units have a higher " Bias " ratio than the OEM takeoffs. The higher Bias ratio does create higher loadings on the internal components...which of course accelerates the wear problem. So I would expect the OEM take of units to be better for longevity for ordinary street use.

At that point they were just developing the T2R prototype and they offered me a developement unit at cost. It was still pretty pricey and the Eaton had just come out so I went with that.

So far the Eaton has taken everything I can throw at it without a whimper. But if I went to a larger diff, such as a 9", I would definately go back to a Torsen. The incraese in traction during cornering is amazing...particularily in the wet.

Hopefully that hasn't " muddied " the waters too much.

 

I'm planning on a ~340-350 FWHP motor with a small shot of nitrous (50-75). I really doubt I'll ever use slicks on the 10 bolt. I just don't think it would hold up. With street tires or some drag radials (245-255 width) would I be ok with the OEM torsen or should I go with a eaton?

This will be with an automatic so it should take some of the stress off of everything.

This is a everyday street car (even thought it sucks driving a carbed, cowl hooded, non-ACed car all year) so I need drivability.

Also I will be going with 3.42 or 3.73 gears. I haven't decided which yet since I'm still debating between a th350 or a built 700r4.

But anyways I am just trying to figure out what I should do with my rear-end. I will probably put a good stud girdle on it also. And MAYBE moser c clip axles.

I know a guy running a 02 TA automatic with a SLP catback exhaust and a 150 shot of nitrous. Running 7.7's in the 1/8th with wheel spin and with his stock rear and its still going strong.

 

We have over 100 passes with slicks behind a 305 then a 350. So far the only noticable wear is the tires always wanting to move in same direction. When I originally installed the unit, it felt like a regular limited slip unit. Now it almost feels like a spool. I started this thread because of this change. Torque and Horsepower will force us into a 12 bolt or 9" shortly.

Other than the restriction on wheels turning opposite direction, there is no wear evident in rear assembly. No loose pinion, carrier or axle bearings. I am using a girdle cover and have welded tubes to center section. This should help reduce wear by limiting deflection. There was a fair amount of fine blackish shavings on magnetic plug, no real sign of where it came from. Most likely tooth wear from gears, but could also come from inside carrier.

We have gone a best 60' of 1.61, with 4.10 gears and 2600 RPM launch with 3500 stall converter and TH-350.

We have used synthetic from day one. D#@% expensive oil. This is the first oil change, when I saw plug we pulled cover. Really suprised the 10 bolt has lasted this long. It is 1992 RS rear w/28 spline axles. When I originally pulled rear, car had 135,000 miles on it and axle bearing surfaces had zero wear. We have already destroyed a 1999 Bravada locker (30 passes behind 305). Car looked real funny wiggling as power went from one wheel to other on burnouts.

 

Do you think a regular OEM torsen would hold up with my setup? Like I mentioned I doubt it will ever see slicks.

 

What really stres's and wears a Torsen is applying power exiting corners...so that is not likely to happen when Drag Racing....unless something goes horribly wrong

 

Keep an eye on things. Blackish shavings are usually bits of carrier housing that have started to wear. Could be first sign of trouble...or just normal break-in particles. If you keep finding more Blackish shavings, inspect the ends of the worm gear shafts where they ride in the carrier housing. ANY indication of enlongation or ovalizing of holes is a sure sign that the carrier is starting to wear.

Edit:Re-reading your original post I realise that I mis-read it. A Torsen will normally act like an open diff when both wheels are jacked up and one wheel is rotated by hand. ie: Wheels will rotate in an opposite direction.

Sorry about that My bad.

Definately could be an indication that things are starting to go bad. Fair amoumt of Blackish shavings and the fact that both wheels now rotate in the same direction could very well indicate a problem. Check it with tranny in neutral and both wheels with no load...wheels should rotate in opposite directions. This is the normal action for a Torsen.

Possible causes for abnormal action. Holes in carrier starting to elongate or have excessive play. Binding or damage to worm\spur gears. Material jammed in housing.

 

Does not matter whether in gear or not. Tires want to move in same direction. If in gear they just don't move. Actually behaves like a spool, unless you push really hard in opposite directions. I did not disassemble carrier, internal gears seem to move okay. C clip block is free, no sign of jamming or wear. I am thinking it might be wise to pack carrier with JB Weld........ Just kidding. Will order new rear next week.