LSD vs Auto LSD

"Here there be dragons..!"

Not looking to get too deep into this but can anyone who understands the new "Auto LSD" issues help me decide if I should or should not install a fully mechanical LSD? I have a Toyota LSD third member that I was thinking of putting in my 2010 4x4 Tacoma. Its not an off roader truck, its an everyday driver with an occasional off road adventure but spends a lot of time on ice and snow. I understand how the newer "Auto LSD" works I just dont know how the mechanical LSD will interact with it and if it will be of any great benefit. Thanks in advance.

 

Wheel.....I done bought the darn thing after I was told I did not have a LSD. Then I checked the window sticker that cometh with my chariot Tacoma and discovered that it did inded have "Auto LSD". Then I discussed the issue with the stable master, (Service Manager) and well, all I have to do is toss it in. I do have traction issues now in the rain but in "Auto LSD" it is not all that bad. But you can ruin your sheetmetal if you have to have people push you out of a stuck spot in the mud, snow, or ice, the sheet metal is getting thinner to save weight and add MPG, it literally dents the bed and tailgate up with palms and shoulders when you have to get pushed out, and thats a heck of a time to have to say, "I wish I woulda..".

 

Right. See I knew I was missing something. Its a Toyota mechanical LSD. Its the entire third member, just switches right out.

 

I'm not sure I'd change to mechanical LSD for any on-pavement use - including rain, snow, etc... existing electronic traction control/Auto LSD is designed towards these conditions.

Off road is a little different - you can't enable the Auto-LSD function when you're in 4WD, which is really when you'd most want it. So for tough trails, I can see maybe making the switch - but then going all the way to selectable locker is probably a better choice anyway.

Your scenario talks about being stuck in a ditch. You know than no LSD of any sort will help to keep you *out* of the ditch in the first place, right?

I dunno. I'm still disappointed to find my 2011 has this AutoLSD function instead of mechanical. But that being said, if I do an upgrade I'm going to go to selectable locker since that fits how I use the truck.

 

Uhm, that new 3rd member you got - it *is* the same ratio as your existing diffs, right? Stupid question I know, but you'd be surprised at what people will do, or don't know not to do.

 

Hi Steve thanks. It matches the ratio ok. I was lined up to have the dealership install it then we all kind of backpedaled and now everyone is scratching their heads. Warranty issues and all. I am sure they will work together ok but what will it do to my warranty? (Service Manager is checking now). Its a Toyota add on part right out of the box but will it conflict with the "Auto LSD" computer and features? No one seems to know. The "Auto LSD" is a spinoff of race vehicles and really does work well but like you said, what about "real off-road"? The customer rep was trying to point out advantages of "Auto LSD" over the differential LSD and how the LSD clutches wear out after time, well "Auto LSD" will wear out your pads no? Course brake pads are easier to change. Selectable is great but I dint want to tear too far into this.

 

AUTO LSD (2WD) is the same mechanical function as TRAC (4WD-Hi): Both are traction control (limited slip) without engine output regulation. They just don't use the same name. TRAC in 2WD has engine output regulation... but sometimes you need to rev it up and that is why the push of a button to turn off TRAC (2WD), which turns on AUTO LSD.

When you go into H4, the TRAC system looses the engine regulation and becomes AUTO LSD but on all four tires, they didn't call it that name sadly.

Before you mess with a new truck, in warantee still, that has a great stock traction system, learn what it is you have and try it one winter.

 

Good info davidk. The problem however is TRAC shuts off in 4L leaving 2 open diffs. Here a mechanical LSD makes sense.

 

Ya he says he has a "2010 4x4"

 

yellow wire mod. search it

 

So, stay in H4... it will do better with TRAC than L4 anyway... The only exception is steep grades... for that he should have gotten the Off Road TRD so he could have A-TRAC or Rear Locker in L4.

All is not lost, however... He can have TRAC in L4 by performing the YELLOW WIRE MOD !!! It is for all non A-TRAC 4WD Tacomas 2009+

They report great advance in ability with TRAC in L4 (or call it AUTO LSD in L4)!

 

Your making this into something bigger then it should be. Swap them and be on your way with a true LSD installed. The auto-lsd crap will kick in even less if at all because both wheels will be spinning at the same time vs one faster then the other when you have an open diff. What auto-lsd is the brakes/abs taking control. There are no additional wires or computers that go to the rear end that control any of this stuff either.

There was a guy on a different forum who had an 09 xrunner that he put in a mechanical lsd with no effects to the traction control crap.

 

Thanks, its good stuff guys thanks. I really appreciate it. I had a 2000 V6 Access Cab TRD with the E-Locker and never had to use the E-Loc. I put about 18000 miles on the truck last winter and it was one harsh winter. The 4x4 and the right tires saved my hiney several times. I kind of leaning to just put the darn thing in and see how it goes but I do so hate being along a semi truck on the mountain roads passing them going up hill in the blowing snow at night and the darn truck starts to lose traction.

 

I have thought about this too, but have not pursued due to my concern that with 2 LSD systems in place, it's not clear which one will react first, or if they end up reacting at close to the same time and begin to fight each other to lock/unlock. It just seems a bit too much. Now if it was a switchable locker, then that makes some sense to me in combo with the auto-lsd, but it just seems like there may be "conflicts" in having 2 LSD systems in place. In theory anyway...

 

I think you should run with one or the other.

The Auto LSD is going to use wheel speed sensors to function.

If you put a mechanical LSD - then, that'll somewhat defeat the purpose of what the Auto LSD is trying to do. It might confuse the crap out of the system.

But who the hell knows....If you're gonna do it....do it and let us know how it works.

 

Why do you call it crap? You don't even have an '09+ Taco.

I had an '05 before the '10 and can tell you it is like night and day in improved traction.

What a great idea to use the brakes instead of clutches inside the differential, to achieve the same affect... slowing down a non-traction wheel.

It works, it is from Toyota, it is guaranteed.

 

x2

I had this problem last night while trying to get up a steep hill which was icy. I slid down it and scared the wife.

 

The only problem I have with the new computer controlled LSD is that it retards the engine, and when you need engine speed AND LSD, you can't get both...

 

ONLY IN 2WD TRAC, NOT IN 2WD AUTO LSD and NOT IN 4WD.

(you see friends, even though this information has been posted by me for a year and many others, people still don't know how it works)

This used to be my signature... It is the 9 drive modes we '09+ Off Road 4WD Tacomas have:

1) 2WD: VSC and TRAC active, engine regulated ('Limited Slip Lite').

2) 2WD: 'AUTO LSD' ('TRAC OFF MODE'). No engine regulation for 'strong' limited slip.

3) 2WD: 'VSC OFF MODE' (TRAC is off for 'open differential').

4) 4WD-Hi: VSC and TRAC active. No engine regulation for 'strong' limited slip.

5) 4WD-Hi: 'VSC OFF MODE' (TRAC is off for 'open differentials').

6) 4WD-Lo: VSC and TRAC are both off in L4 ('open differentials').

7) 4WD-Lo: 'A-TRAC' on gives a 'locker-like, super strong' limited slip, front and rear.

8) 4WD-Lo: Rear Differential Locked and open front differential (A-TRAC off).

9) 4WD-Lo: RR DIFF LOCK + A-TRAC on, 3 MPH limit.

Only the Off Road 4WD Tacomas have a hydraulic brake booster (for the A-TRAC system).

Now, the 2WD Tacomas have modes 1-3 and the Off Road 2WD Tacomas have 1-3 + a locking rear differential.

The 4WD non-Off Road Tacomas have modes 1-6.

 

and only TRAC in 2WD does...