auto LSD- what is the point?

No offense intended, but Auto LSD is not like a locker.
Auto LSD has a 7 mph +/- slip factor, with progressive torque transferring. It's only difference from a real LSD, is that it has no pre-determined "break away" torque setting. It is like a mild street limited slip. A locker is quite different. (no slip, no give, binding in any high traction situation)

 

Toyota did say: "Auto LSD and Rear Differential Lock perform similar functions"

From Toyota: Auto Limited Slip Differential (Auto LSD) -- Auto LSD uses the TRAC system to achieve the capability of a Limited Slip Differential (LSD) when driving in 2WD mode. (On a 4WD vehicle, Auto LSD only operates when the vehicle is being driven in 2WD mode.) Because Auto LSD and Rear Differential Lock perform similar functions, vehicles may have one system or the other, but not both. While Auto LSD components are similar to those in the TRAC system, there are important differences.

Glad you responded Hemi,

Please tell us why the 'AUTO LSD mode' made both rear tires spin and kick up sand, and the normal TRAC in H2 did not. What I experienced was a 'posi-traction' like take off in AUTO LSD and a 'mellower' take off in TRAC (engine output regulated). Is engine output regulation the only difference between AUTO LSD and TRAC?

I thought I read a while back where you (?) said A-TRAC was like AUTO LSD front and back..?? A-TRAC is a 'pseudo-locker' (in your words, and I agree).

Is AUTO LSD stronger for us with the OFF ROAD/ A-TRAC Tacomas (because of the hydraulic brake booster, than for the non-Off Road and 2WD Tacomas with the vacuum brake booster)?

Thank you!

PS I modified my signature (9 drive modes) based on the continued desert tests and discussion here.

 

Yep ... great information. Much appreciated. Much better than the manual.

 

Thanks... I hope you saw this post: http://www.tacomaworld.com/forum/te...uto-lsd-explained-easy-understand-i-hope.html

as you can see by the discussions between Hemi and I, there is a lot of 'hidden' details, and I am trying to expose them and put them in easy to understand terms. Isthatahemi and others here have been very helpful.

 

Similar yes, but not the same....i think what was being stated here was that they do not function on the same axle at the same time. And Toyota's wording is confusing, they should just simplify it by saying ALSD works on both axles in 4WD, instead of calling it TRAC. (Like Nissan does - "ABLS")

Yes

If I did in fact say that, ( A-TRAC was like AUTO LSD front and back.) I have revised my opinion.

TRAC is like Auto LSD. A-TRAC is like lockers, minus all the binding.
I'm not disagreeing that Auto LSD is very effective, especially on the OR models. On sand, I would say the difference would be negligible, as traction is roughly equal at both tires. We are splitting hairs though, ALSD is very effective, I imagine you must use a lot of throttle on sand. Using light throttle, the difference between the locker and ALSD is noticeable,as it allow one tire to dig more.

Having owned and driven both, there is a noticeable difference in effectiveness. I also notice my brakes are grabby and non-linear on my 2010. On my '09 (Non OR) the brakes were "normal"

 

"And Toyota's wording is confusing, they should just simplify it by saying ALSD works on both axles in 4WD, instead of calling it TRAC. (Like Nissan does - "ABLS")"

One thing different, is that AUTO LSD (in H2) is not recommended for continuous operation, while TRAC in H4 has no such warning (pg. 184 owner's manaul). High speed will not shut off TRAC in H4, but does shut off AUTO LSD.

Thank you... I think we now have beaten the dead horse enough, and I am satisfied with your response... I have edited my signature again this morning, making it more simple. We know there will be new Tacoma owners and new members to TW that will have the same questions in the future!

The OFF ROAD TRD 4WD (A-TRAC equiped) is by-far, a most awesome machine and has big advantages in traction ability over all other Tacomas and pehaps many other makes, as equiped from the factory!

The hydraulic brake booster enhances the performance of the traction systems.

TRAC in H2 is 'lite LSD' (engine output regulation)
AUTO LSD in H2 is 'strong LSD' (no output regulation)
TRAC in H4 is 'strong LSD' (no output regulation, like AUTO LSD on both axles)
A-TRAC in L4 is like lockers front and back, without binding.
The Rear Locker is still there as well, if A-TRAC doesn't get you through!

 

Man, my head is spinning from reading this thread.
One simple question, if I buy a two wheel drive 2010 Tacoma regular cab with automatic transmission will I get LSD?
Thanks,

 

Yes. According to Toyota's website.

http://www.toyota.com/tacoma/features.html

 

Crom,
Thanks for the quick reply.

 

Glad to help.

 

wayr iz tha spell chek???

 

Looking at the 05+ Tacoma OEM repair manual, it seems to indicate that VSC equipped vehicles have the hydraulic brake booster and the non-VSC equipped vehicles have the vacuum brake booster.

 

Interesting observation. It makes sense. I knew that previous years of the Tacoma had it, at least some of the technical manuals I read suggested that...

Welcome to the forum!

 

Seems to me, I saw a tech sheet that showed the 2009 and newer Tacomas only had the hydraulic booster if they were A-TRAC equiped (ie. OFF ROAD TRD 4WD)... Hemi or ? can dig it up... I am all loaded up for Baja in the morning...

Crom... dude, sorry you are unable to join us! HB Murphy is going to caravan with us... Look fior the photos to be posted soon after we return!!!

 

I think our newfound friend ToBeFrank is correct. Look at this diagram:



Remember VSC was optional equipment prior to 2009 and the above chart shows that with the older 2008 models with VSC had the hydraulic booster. Toyota made efficiency improvements to the vaccuum brake booster in the 2009 models. It is presumed that these improvements allowed the vaccum brake booster to do the job that the hydraulic booster used to to. However, A-TRAC, HAC, DAC still require the more powerful hydraulic booster.

David, Have fun in Baja, I wish I could go!

 

Actually, I'm wrong. My previous post was while looking at the repair manual, but without looking at my truck. I have a '10 Prerunner with OR and looked to see what I've got. I definitely have the vacuum booster. I have the big round can with the tube coming from the intake going into it.

 

Thanks for letting us know that. Beginning with the 2009 models only the 4x4 Off-Road Models have the hydraulic booster. What we do know is that some 2008 and prior models had the hydraulic one, but I guess we still don't know why exactly.

 

Crom, HB Murphy and I are back from Baja, and it rocked! See the photos in the Mision Santa Maria thread (Off Roading forum)... some already posted, more later...

A-TRAC was awesome, no rear locker needed!

 

A follow up to the Memorial Day 2010 Mision Santa Maria trip test of A-TRAC:

My third time in with a 4WD Off Road Tacoma.

The previous two Tacomas ('01 and '05) required the REAR DIFFERENTIAL LOCKER to climb the Widowmaker and other grades with little difficulty.

The 2010 had A-TRAC activated when in L4, which was at least for 1/3 of the distance to/ from the mission.

The road was rougher and more difficult than any of the previous trips.

The A-TRAC performed perfectly and I NEVER needed or engaged the REAR DIFF. LOCKER!

Being that the road was worse, plus the 3 foot deep water/ mud bog was no problem either (an open diff. 4Runner required pulling through), I have to conclude that A-TRAC is a superior traction system to lockers (front and rear) in the conditions I have used it on: deep sand, steep climbs, deep water/ mud.

The vehicles on our trip with a front locker had to frequently un-lock it any time a sharp turn was required, which was constant on that road. A-TRAC has no effect on steering abilty.

If you don't have an '09 + Off Road 4WD Tacoma (yet) to experience A-TRAC (Active Traction Control), I just am reporting this so you can look forward to this technology and how well it has worked for me in the deserts of California and Baja California, Mexico. I have been four wheeling since the 1960's and A-TRAC is the most impressive traction system I have ever seen or driven.

See my Memorial Day 2010 trip report in the Off Roading forum.

 

I wish i had atrac... trac seems to work really well too. just not as tight as atrac