Diff Lock vs. 4Hi vs 4Lo

I've never been in a 4x2 TRD Offroad. Do you just push the locker botton anytime (any gear & speed) for the locker to engage?

 

In order to lock the differential, it think would need to be still. I would kind of like to try and lock mine without being in L4... Is there a trick, fuse or wire to allow this (since it is available in 2WD Tacomas)?

 

there is a mod that you can do that can allow you to lock the locker in any gearing (h4,h2,l4,l2) i think it is called the blue wire mod. basically you just cut a wire and it tricks the computer into thinking it is grounded. but you should be stopped when you engage the locker no matter what

 

Yah, I found it... but it is a relay addition not just a wire cut in the newer Tacomas.

I decided I can go everywhere with TRAC in H2 and H4, so don't 'really' need the locker in those modes... It would be just for fun and more drive modes than my list already has! LOL

 

David K - Great post!! Thanks for laying this out!

 

Thanks ... see my more detailed explanation in the Technical forum!

 

Hey, BravoZulu, are you good now? We want you to know what you got and how to use it!!

Low Range, more torque to one tire in the front and one in the rear...

Rear Locker divides that torque to both rear tires equally (if your tires spin and you don't move).

A-TRAC ('09/'10 TRD Off Road 4WD)... Limited Slip front and rear.

 

I don't know if this was ever answered in full, so I'm going to ask it as well.

Janster said it might help with boat loading... but couldn't you just go to 4H --> 4L --> 4L locked? you are driving straight and slow.

What situations would you need 4H locked?

What situations would you need 2WD locked?


The only thing I can think of in my limited experience is speed or steering... but I don't know what applications that would be.


Keep in mind I ask this for pre-2009 years.

 

Anytime one of your rear tires spins (and it is a pre-'09 or doesn't have TRAC/LSD).... and specially for the 2WD only Tacomas (ie. PreRunners).

 

... which means I can simply go 4L+locked. Is there a situation where I don't want to be in 4L?

PreRunners already have 2WD lockers since there's no 4WD switch. If it's a non-prerunner, I don't think a locker was an option, plus there's still no 4WD switch.

 

A side note......ATRAC deactivates at anything faster than 5 mph wheelspeed when the rear diff is locked. To really tear out of a situation, unlocking the rear diff may help.

 

Well, in L4 the gearing is so low, you can't drive very fast... It is for crawling up or down steep, rocky grades or crawling through deep snow or mud... SLOW power/ torque 4WDing is L4.

The addition of the locking rear differential is to have BOTH rear tires getting equal power. An open differential allows the tire with the least traction to spin... So, if one of the two rear tires leave the ground... it will spin and the other one, still on the ground, is useless.

TRAC (in H2, H4) and A-TRAC (in L4) are limited slip systems that will divert power to the tire with traction by braking the spinning tire. (TRAC in H2 in addition to braking, can also regulate power to help stop spinning).

AUTO LDS (TRAC OFF) in H2 brakes the spinning tire heavier than does TRAC to assist getting unstuck in 2WD.

 

I'm going to keep pounding away here

So in what case do I need both high speed and locked? So far, I see two situations:

1. I'm driving fast enough that forward momentum is going to overcome any differential issues
2. I've come to a 'stuck' situation where I need to lock up and crawl out.

 

Maybe on a drag strip?

Seriously, you don't want high speed if you're four wheeling over difficult terrain... you will break something... that's the beauty of 4WD... the added traction permits you to NOT risk damage caused from using momentum to get through a low traction area.

The rear locker (in L4 only, 4WD models) is just for getting moving when you would otherwise be stuck.

What I haven't discoverd yet is if the new A-TRAC (in L4) WITHOUT the rear locker will work as well at moving through mud or up a steep grade. I was hoping to test it on the Mision Santa Maria road next month... However the heavy rainfall damage in Northern Baja may delay that trip. Last time there (2007): http://vivabaja.com/msm

 

Updated mode operation data from Tech page:

Another way to word the drive mode selections:
Normal Mode (no pressing of switches):

2WD (H2): TRAC & VSC on. TRAC (Traction Control) uses brakes and regulates engine output to achieve LSD (Limited Slip Differential action). VSC (Vehicle Stability Control) keeps truck moving where desired, on slippery roads

4WD (H4): TRAC* & VSC on (*engine output not regulated)

4WD (L4): (no trac, no vsc)

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

Short press of VSC OFF switch:

2WD (H2): AUTO LSD on (no trac, no vsc)

4WD: no change, from above

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Long press (hold 3 seconds) of VSC OFF switch (when stopped) for OPEN Differential(s):

2WD (H2): All off (no trac, no vsc, no auto lsd)

4WD (H4): All off (no trac, no vsc)

4WD (L4): no change (no trac, no vsc)

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

Press A-TRAC (Active Traction Control) switch:

4WD (L4): A-TRAC on (provides the advantages of TRAC or LSD while in Low Range 4WD). Unless pressed again, A-TRAC will always come on when shifted into L4, from now on.

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

Press RR DIFF LOCK switch:

4WD (L4): Locks the rear differential. Can be used with or without A-TRAC activated. A-TRAC only active to 5 mph with the rear differential locked.