LSD for the street: worm gear or clutch type? (toyota tacoma): Grassroots Motorsports forum: Grassroots Motorsports Magazine

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July 8, 2009 8:04 a.m. problemaddict Reader

Hey all, I'm looking to get an LSD for my '03 Tacoma S-Runner. It should transform the way this truck performs. So the question comes down to which type? The truck is a daily driver, sometimes tow vehicle, infrequent autocross and drag strip use as well, but nothing serious. The two available LSDs are:

TRD/Kazuma/Eaton clutch type - $299 This is/was a dealer option and i think a factory option on other Toyota pickups. I can't find much info on it, like whether its a 1-way or 1.5, or what. The site where its listed says "pre-tensioned to 400 ft-lbs as opposed to the 200ft-lb pre-tension units the factory installed LSD."

Detroit TrueTrac worm gear type - $450.

I reread the recent "Whats teh Diff" article w/ the S2000 and it leads me to believe that the clutch type may be a bit sketchier on the street? Maybe a handful in the rain/snow? But then i also factor in that it was a factory option, so how hairy could it be?

The Detroit, on the other hand, could be more mild mannered? but could also unload in the rain/snow. THat, and its $150 more...

So, any experience w/ TRD/Kaz/Eaton and/or Detroit stuff anyone could share? Does anyone have one type of LSD and wish they had the other? why/why not?

thanks!

Mike
July 8, 2009 11:06 a.m. iceracer HalfDork

I have the "Trac-loc" differential in my Liberty. It is a clutch type. Sometimes I hate it, sometimes I'm glad I have it. On ice or very limited traction it tends to break the back end loose making it necessary to shift into 4wd. which eliminates the problem.
July 8, 2009 1:51 p.m. foxtrapper SuperDork

I'm almost positive that Toyota never put a limited slip in their trucks. They went with the e-locker exclusively.

The Eaton type clutched limited slip was OEM on Volvo's and such. Nice unit, it acts like an open differential until you get too much slip, then it locks up. That seems like a nice setup to me (never drove one).

The e-locker seems like the best imo. You're running an open normal differential which is very docile and easily control. Throw the switch on the dashboard to lock the differential when you need it locked.
July 8, 2009 1:59 p.m. GameboyRMH SuperDork

E-lockers could be a good choice - nothing to wear out and they're as street-friendly as an open diff, but I imagine an LSD could be quicker for drags (I doubt diffs would help for AutoX in this case). Once a locker locks up...it's locked up.
July 9, 2009 2:36 p.m. problemaddict Reader

The TRD clutch type was OEM on some Tundras, but never in Tacomas. However the two trucks share the same diff/carrier.

I'm not really interetsed in a locker or e-locker. I'm looking for a diff that will help put power to the ground in spirited driving and autocross. When i autocrossed this truck, i had one-wheel-peel throughout almost the entire run. Why would you say an LSD wouldn't help for AutoX in this case?

I guess what i'm really looking for is anyone with experience with both worm-gear types and clutch type diffs and could compare/contrast how they might act in my application?

Thanks!
July 9, 2009 3:25 p.m. Strizzo Dork

the clutch type will always put at least however much power to the "grip" wheel as its pre-tension gives. when theres more grip on the spinning wheel, this puts more tension on the clutch and it grabs more. not sure about the worm gear, but i think it needs at least a little preload from the "slip" wheel to start locking up (so if one tire were in the air, for example, you'd have to tap the brakes to make it grab), in which case i think some can fully lock up. the clutch type will almost never be fully locked.

iirc, the aftermarket e-lockers are of the LSD type until you hit the switch to fully lock them up. not sure how the toyota e-locker acts though
July 9, 2009 5:21 p.m. EPcivic New Reader

I had the factory LSD in my Tundra, and it actually worked quite well. That being said, for a mostly street application, I would go with the Tru-Trac helical style for only $150 difference. All clutch diffs will wear out eventually, and if you do a lot of aggressive driving, some will wear out quite quickly. The helical ones are pretty much bulletproof and don't wear like clutches do. They also tend to be smoother in their action. The big downside to the helical style is that they open up if you completely unload the inside tire. This can be a problem off road, or on a racecar that lifts the inside drive wheel. For your application, I wouldn't think either of those situations would be likely.

-Chris
July 9, 2009 6:33 p.m. wherethefmi Dork

Strizzo wrote:

the clutch type will always put at least however much power to the "grip" wheel as its pre-tension gives. when theres more grip on the spinning wheel, this puts more tension on the clutch and it grabs more. not sure about the worm gear, but i think it needs at least a little preload from the "slip" wheel to start locking up (so if one tire were in the air, for example, you'd have to tap the brakes to make it grab), in which case i think some can fully lock up. the clutch type will almost never be fully locked.

iirc, the aftermarket e-lockers are of the LSD type until you hit the switch to fully lock them up. not sure how the toyota e-locker acts though

Clutch type are much better than worm gear, you'll always have traction, don't the helical kind act more like an automatic torque biasing unit? It'll keep moving power from wheel to wheel in limited grip situations, causing all sorts of wonky handling, rjust my .02 and it's probably not even worth that much
July 11, 2009 1:14 a.m. ww SuperDork

I have a couple of each. The worm/torsen units are unlocked until you start to slip and require there to be at least some grip on both wheels. They're torque "multipliers" and require some torque on the other wheel to "multiply" in order to work and they never wear out.

The clutch type can "chatter" while going around a turn, they don't require the "slipping" wheel to have any traction at all to work and they need rebuilt over time to replace the plates with the friction material just like a clutch.

I've used both on the race track and I prefer the torsen as long as the suspension is configured to keep both drive wheels on the ground.
July 11, 2009 4:55 a.m. problemaddict Reader

Thanks guys! i'm gettin some good insight. Would either type be more/less helpful for "steering with the throttle"? The open diff really kept me from being able to get the back end to rotate on command.
July 11, 2009 3:35 p.m. Appleseed HalfDork

I've found that the Eaton on my Caprice tends to try to make the car push more than the old worn out one did. I assume this is due to the positive locking action. But, in lower traction situations, like snow, I drive with the throttle, rotating on command. In fact, that's the only way I can steer that tub.

I've also heard that worm gear diffs don't like the high shock loads of drag racing.