VSC Off LSD On

[nmhuntr]

OK

Having a new Tundra I am wondering how everyone uses the VSC/LSD? If I go to 4WD it appears that the VSC is off and LSD is on? If I press the off button for the VSC then the VSC goes off and the LSD comes on and if I hold the button a few second the VSC goes off. So what in the world is the correct way to off road with this thing? I have a college degree but I cannot follow the owners manual for anything. I searched for Limited Slip and there were no results which shocked me...I feel the search engine is slipping so any input would be appreciated.

Greg

P.S. I know it is not really a Limited Slip...The term is used here for discussion purposed only.

[Deznutjob]

Originally Posted by nmhuntr

OK

Having a new Tundra I am wondering how everyone uses the VSC/LSD? If I go to 4WD it appears that the VSC is off and LSD is on? If I press the off button for the VSC then the VSC goes off and the LSD comes on and if I hold the button a few second the VSC goes off. So what in the world is the correct way to off road with this thing? I have a college degree but I cannot follow the owners manual for anything. I searched for Limited Slip and there were no results which shocked me...I feel the search engine is slipping so any input would be appreciated.

Greg

P.S. I know it is not really a Limited Slip...The term is used here for discussion purposed only.

This site is still kinda fresh and there is just no info on limited slip or vehicle stability control yet. If you get it started and the info starts rollin in the next guy will say, "hey this site has great LSD and VSC info!" Speaking of LSD, by the way you were explaining your problem I thought you might have been sampling some LSD bro.

[TUNDRAWOODY]

HERES A POST FROM ANOTHER SITE.




Re: Help me understand my traction control and VSC.

--------------------------------------------------------------------------------

I think I have a better understanding now that I looked through the Tundra brochure. I'll re-type the relevant sections here:

BRAKE CONTROL SYSTEMS

Tundra offers an advanced brake control system that includes massive vented rotors, front and rear. But it is the software that makes Tundra's brake control system so comprehensive. In addition to an ABS, Tundra also comes standard with:

Traction Control (TRAC)
TRAC helps maintain traction on wet, icy, loose or uneven surfaces. When one of the wheels begins to slip, TRAC applies a wheel brake individually and reduces engine output to help assist the driver with control of the vehicle

Vehicle Stability Control (VSC)
VSC helps prevent two factors that frequently cause drivers to lose traction during cornering: front wheelslip and rear wheelslip. VSC monitors your steering angle and compares it to the direction in which your vehicle is actually traveling. If VSC detects a loss of traction, two things happen to help correct the problem: First, engine output is reduced. Then, brake force is applied to individual wheels as needed.


AUTOMATIC LIMITED SLIP DIFFERENTIAL (AUTO LSD)

Auto LSD uses the brakes to simulate the action of a mechanical limited slip differential. By applying brakes individually to wheels spinning with no traction, torque is sent to the wheels with grip. Even a 4x2 Tundra can dig itself out of many difficult low traction situations.

Typically, engine torque is distributed to the rear wheels through an open differential. An open differential sends power down the path of least resistance. Great for turns, when the outside wheel has to spin faster than the inside wheel. But not so great if a wheel loses traction, because the differential will send all of its torque to the spinning wheel. With Auto LSD, Tundra will apply brakes to the slipping wheel. This increases resistance at the wheel with slip, feeding power to the wheel with grip. Tundra will advance forward until traction is restored to both rear wheels.


OK - so back to the modes I originally listed:
1) Traction control off, Auto LSD
2) Traction control off, Auto LSD, VSC Off
3) Traction control off, VSC off (no Auto LSD)
To that I guess I should clarify mode 0 (default):
0) Traction control on, VSC on, Auto LSD off

In default, the traction and VSC modes are on, and the differential acts like an open differential. That makes sense for normal driving.

Mode 1 makes sense if one of the wheels is stuck. You'd want the differential acting like a limited-slip differential and apply power to the wheel that's not spinning.

I still can't figure out modes 2 and 3, even with the above explanation. Seems like it might be something for off-roading, but I don't know for sure.

[08CMAX]

OUCH it hurts...no more! My dad works for Toyota and said the auto LSD is BETTER than a mechanical limited slip seen on domestics. I'll have to ask him again why that is.

[TOPSECRETTSI]

The tundra also has a mechanical limited slip the auto lsd just lets it act like a locker would. When the traction is limited to the point that the mechanical action cannot be activated the auto lsd comes in and bracks the wheel that has no traction which in turn activates the mechanical limited slip. I know this not only from the pics I've seen of the rear diff but also from the fact of with the system turned off it will still lay two strips of rubber Gm still has the best though a true mechanical locker.

[nmhuntr]

Originally Posted by TOPSECRETTSI

The tundra also has a mechanical limited slip the auto lsd just lets it act like a locker would. When the traction is limited to the point that the mechanical action cannot be activated the auto lsd comes in and bracks the wheel that has no traction which in turn activates the mechanical limited slip. I know this not only from the pics I've seen of the rear diff but also from the fact of with the system turned off it will still lay two strips of rubber Gm still has the best though a true mechanical locker.

I took mine off road yesturday and if I turn the VSC off the Auto LSD comes on. Makes sence...Problem is when I place it in 4WD I thought the Auto LSD would come on agin but I got no indication that it was activated

Any Ideas if it is suppose to be on in 4WD...If I designed it I would have it on. Thats like installing a locker but when you put your truck in 4wd you take it out. Doesn't make sence to me.

Thanks

[oldgringo]

VSC should be used for normal highway driving (2wd) but where rain or ice etc make it possible to skid or completely lose traction on 2 or 4 wheels. It has worked exceptionally well this winter in the PNW. Lots of compact snow and black ice.

LSD turns on when you shut off VSC with a first push of the button. LSD is used primarily 2wd when you might need to rock the vehicle or get traction while accelerating. VSC would want to shut down engine rpm and apply direction control braking. You don't want VSC working in mud, sand, etc. It'll work against you and the truck. Plus it has a noisy little alarm that goes off and scares you @#$$^&.

At the point where you get stuck or feel engine revs go down (when you are gassin' it), stop and push to engage LSD. 2wd LSD pushes you very straight and very far.

I only needed 4x4 to go thru very deep drifts and long pulls.

When you go to 4wd H or L, VSC is shut off by the switch, automatically, and both of your axles work somewhat like a LSD. It behaves similarly to a differential lock on older 4x4s driving power thru all four wheels, but becuase it is electronic and pretty well designed it should not use the hp that locking the transfer case does.

It's pretty slick. So far all three systems have worked well for me...once you figure out what they'll do!

The only thing I added was four 70lb sand tubes over the rear wheels for better traction.

[nmhuntr]

Originally Posted by oldgringo

VSC should be used for normal highway driving (2wd) but where rain or ice etc make it possible to skid or completely lose traction on 2 or 4 wheels. It has worked exceptionally well this winter in the PNW. Lots of compact snow and black ice.

LSD turns on when you shut off VSC with a first push of the button. LSD is used primarily 2wd when you might need to rock the vehicle or get traction while accelerating. VSC would want to shut down engine rpm and apply direction control braking. You don't want VSC working in mud, sand, etc. It'll work against you and the truck. Plus it has a noisy little alarm that goes off and scares you @#$$^&.

At the point where you get stuck or feel engine revs go down (when you are gassin' it), stop and push to engage LSD. 2wd LSD pushes you very straight and very far.

I only needed 4x4 to go thru very deep drifts and long pulls.

When you go to 4wd H or L, VSC is shut off by the switch, automatically, and both of your axles work somewhat like a LSD. It behaves similarly to a differential lock on older 4x4s driving power thru all four wheels, but becuase it is electronic and pretty well designed it should not use the hp that locking the transfer case does.

It's pretty slick. So far all three systems have worked well for me...once you figure out what they'll do!

The only thing I added was four 70lb sand tubes over the rear wheels for better traction.

Got the DC so I have a 6.5 ft bed for my quad. The only place I need 4wd is up in the mountains and I never go without the quad in the back

[can't stop spinning]

The one time I tried using the lsd, it sucked

I was backing into a parking stall that was 1/2 pavement, and the other half had about 4" of snow and ice. At first I had the truck in normal mode, vsc and tcs on lsd off, and spun out while sensors beeped at me. I turned the lsd on and still spun the tire on the snow. The auto lsd didn't act like a real lsd in that situation.

I ended up having to put the truck in 4x4 to finish backing up.

I know it's rather minor, but the one time I wanted the lsd to work, it didn't work as well as my other vehicles with a lsd.

[TOPSECRETTSI]

Thats weird in low traction circumstances my tundra has always spun both tires like it has a real lsd I always assumed it had one? I thought the auto lsd made the regular lsd perform similar to a locker being that even when you don't have enough force to lock the clutches up and activate the mechanical lsd the auto lsd steps in and locks the brakes on the spinning wheel enabling the mechanical lsd and away you go ( a locker like gm has still works better though).

[Ultimate1]

I dont think the locker in my GM worked better. When it did lock, which was rarely, I couldnt get it to release. Driving on pavement turning, the tires would squeal than a loud pop and it was released. maybe mine was a bad one , anyway I didnt like it.

[jtruck618]

Originally Posted by Ultimate1

I dont think the locker in my GM worked better. When it did lock, which was rarely, I couldnt get it to release. Driving on pavement turning, the tires would squeal than a loud pop and it was released. maybe mine was a bad one , anyway I didnt like it.

I have the same deal with my Silverado. One day I stopped on an apartment parking lot and my back right tire was on grass, the left one on dry concrete. I unloaded some stuff and went to park my truck. I was screwing around a bit and I gave it some extra gas which caused my right rear tire to spin in the grass. I guess the rearend locked up because I went straight for about 5 feet and began turning left into a parking space. My truck jumped and popped like I ran over something. I got out, looked around and nothing! I scratched my head, got back in and continued to pull into the parking space. Still a crazy noise and truck felt wierd. I parked, got out again and noticed fresh rubber on the concrete left behind the right rear wheel. I started it up and backed up a few feet. Pow....something popped. Still not sure what the hell was going on. I guess rear was locked and I turned before it unlocked. Since I was on dry pavement it hopped and skidded. It has done it one other time since then. Spun on ice in a parking lot then it skidded and popped. Works great in the mud though.

[TOPSECRETTSI]

Well it's good to hear peoples opinion on the gm locker as I've never had one or experienced them I was just referring to the gm ads that they are better.