Woodbert

Can someone explain, in laymans terms, under what conditions I would want/need to lock the diff on an 03 Surf with LSD?

We have no snow or ice here, but primarily I would need the extra grab in sand, usually, wet beach sand.

Thanks!

knemo77

hey id only use it if i got stuck the first time going through something. or something i was coming up on was very difficult and i knew extra traction would be needed. i could see never using it over the life of truck if your off-road love is limited.

Los Gatos?

Well I would probably try to engage the LSD, then laugh at myeslf, because I would remember that LSDs function automatically and don't need to be "engaged" to work.


If you really have a limited-slip (not a full locker) it will turn on when it is needed automatically.

knemo77

i dont believe that is what he was saying...i believe he wants to know when to operate the locker on a vehicle with lsd.

Woodbert

Thank you knemo77. Yes, that is my question.

I thought it was a pretty straight forward question.

Los Gatos?

You guys are still confusing me. You can't have both a locker and an LSD on the same axle...do you have a locker OR a limited slip? THey are NOT the same thing.

Woodbert

I have a limited slip differential.

I can also lock the diff. My question is under what conditions, not snow or ice, but beach sand, would I want to lock it?

HBoss

I believe he's referring to an LSD in the rear differential & a locker for the center differential.

The LSD is automatic, yes. And you probably want to lock the center diff in low traction offroad situations only.

Even with your LSD as it stands, technically, you could get stuck if you lost traction in one (any) tire. With the center differential locked, your steering at slow speeds (i.e. parking) will be comprised & it will stress your steering & drivetrain components in these situations, and on dry pavement. But you would have to lose traction in one front AND one rear tire (at the same time) to get stuck.

Hope that helps. Again, personally I'd only lock the center diff in low traction, offroad situations. But that's just my opinion on it.

You should read my articles on 4WD & differentials for more detail:

4WD Info

Differential Info

Woodbert

Thanks Boss! I'll check your articles out as well.

And your correct, the lock is for the center diff. I would only use it for going through beach sand and only for a very short period to get out of same.

Thanks again.

Woodbert

One more 4WD question.

I believe mine is called "multi mode" in that I can select 4WD or 2WD and there is a 4WDH and 4WDL.

Since I've had the truck, about one month, it has been in 4WDH mode.

Is there any problem/disadvantage with always running in the 4WDH mode?:confused:

Thanks again.

gwhayduke

Woodbert...
I looked at a 2003 yesterday and if I remember correctly, you have a LSD (torsen) center differential and a rear electric locker.

The torsen allows torque to be shifted between front and rear...whichever has better traction.

The locker just locks the rear axle so both tires are turning at the same rate.

knemo77

only problem i can think of is GaS MiLeAgE, and it might be harder on your drive train than running 2wd, but im not sure. The gas mileae is the real difference.

Los Gatos?

I don't think it's harder on your drivetrain by very much if you have a center LSD...wouldn't most of the power be going to the rear wheels until they started slipping, just like rwd?

BlindSpot

Woody,
I have an example for you. I am currently lurking on this forum, but I own a 2000 V8 Tundra access cab 2wd and a 31' Center Console (boat). When I trailer it down to the Keys, I often have trouble pulling the boat out of the ramp at low tide. Seaweed and other slime cover the ramp and even with LSD one wheel spins and the boat and truck go nowhere. Its not a power issue, its a traction thing. I can get the boat out, but I need weight in the bed to build friction for the wheels. A good friend of mine has a Taco with a locking diff, V6, 2wd. He can lock his diff and crawl my boat right out with no problem. This is in florida and on pavement so there is one example. Lockers are nice to have,but not frequently used.

Robinhood150

As I understand it, the 4th gens do not have a rear locker nor a rear lsd, at least in the US. Both axles are entirely open. The center diff has a torsen lsd which can be locked with the push of the button. The rear lockers were discontinued in the 4runners after 2001 because toyota implemented traction control, so the traction control takes the place of the rear locker.

So the question is when to lock up the center diff. For sand I'd say lock it up all the time. However, since nobody here has significant experience with the torsen diff and how it behaves in sand, I think you (woodbert) should do some testing with all the different settings and let us know what the best setting is.

FYI, Eaton does have an electric locker that will act as an lsd but with a push of a button will lock up. They do not make one for toyotas.

Steve

tom_993

Check this out:
http://www.toyota-4runner.org/showth...hp?threadid=12

It's seems the "transfer case" has been renamed the "center differential."

Darren

No. The transfer case has a differential. The transfer case itself is not a differential.

Also, locking the center differential should not be referred to as a locker, locking the diff, etc. as that causes confusion with a real locker on a front or rear axle. Always specify that it is the center diff to avoid confusion as seen above. Technically, yes, it is a locker, but not a locker. Got it? Good!

Woodbert

tom_993- Thanks for the link. That is an excellent write up that I'll need to read again to make sure I got it right THANKS!

Blindspot- Welcome to the board and thanks for the information! Also very useful. One of the other uses that I want to make sure will get me out of a jam is similar to yours. Our concrete launch ramps here are notoriously slippery when launching watercraft. I don't want my truck sliding down the ramp into the water as I have seen happen before. This is one of the reasons I went with the Torsen LSD and the CDL which were options here. We also frequently launch directly from the beach which presents other 4WD opportunities.

Robinhood- I did get an opportunity last Sunday at a Jet Ski race to drive around on the beach (not towing anything) in just HI 4WD and never even needed to invoke any of the other 4WD setting or CDL. Hopefully this weekend I can do some real world testing and let everyone know how it all went.

Thanks guys!

JD

Your dead right from a factory perspective but where there's a will there's a way

My 91 4Runner is only a couple of weeks away from having a full LSD and an electric locker combined on the rear axle.