Tire power in 4x4 with locking diff

I have a 2004 Tacoma sr5 with the TRD locking diff.
My question is as follows....
When I am in 4low with locking diff engaged should all four tires not spin?
I got stuck in a snow drift and noticed only one front tire was spinning.
Is this normal?...I was under the impression that 4x4 locked both front tires and lock diff locked back tires
Please help

 

Yes that's normal .

 

It only locks in the rear, not in the front.

 

So let's see if I've got this right
In 2wd i only have one rear tire powered?
In 4x4 I have one front and one back?
And in 4x4 with lock diff I have two rear and one front?
What can be done to lock both front aswell?
Thanks

 

Correct.
ARB sells an air locker for the front. $$$

 

Dead on. It's an open front diff, and a selectable in the rear. And ARB does sell a kit, but it's not cheap. Usually 3 wheels is enough for a DD, you must have been in some deep stuff haha

 

And just letting you know, there is a simple mod on here called the grey wire mod that will allow you to lock the rear in 2wd

 

The newer trd offroad tacomas with the locker also have atrac. In 4x4 with the locker and atrac on all 4 tires will spin. I dont know if the older trucks have atrac. Get an Arb upfront and you will be set.

 

They don't. It's open diff

 

Yes they will.

 

The older truck don't have ATRAC is what I meant. They had open diff 2wd(prerunner), locker 2wd(trd prerunner), dual open diff 4x4(4x4), and 4x4 open front, locker rear(trd 4x4).

 

Hey thanks for all the advice guys
I really appreciate it.. I'll def look into the grey wire mod as it would be nice to use 4h locked up
Also.. This air kit for the front lock... What are we talkin here?...$$$
Ballpark
I was in pretty deep indeed... Up to the accord and I have 12" clearance
I was actually out on a local lake ice fishin abd got into a heavy drift on the way back in
Nothin a shovel and some elbow grease couldn't remedy
Thanks again guys

 

"Up to the axle" that was supposed to read

 

Just under a grand for the locker, then you need your rear end setup unless you can do it yourself and a compressor for on board air. Easily out $1500

 

Yes, you are correct there.

A new 3rd member with locker from East Coast Gear Supply(awesome guys) is about $1500. Then add in install, air compressor, air lines, it will add up. Not worth it for most weekend warriors. Unless you have a money tree.

 

If you have manual hubs look into a lunchbox locker, around $350 and easy install

 

Glad to help! That's what this site is for! Welcome ! Be prepare to get addicted to your truck and spend some money haha. The grey wire mod as far as I have read is real easy. There is a plug that goes into your locker acuator I believe it is, and you simple cut it and put a crimp on it, and hook it to a ground. The actuator is behind the lower panel by your left foot in the drivers seat I believe. Don't quote me on everything, as I haven't done it, but have read about it. You can use the locker in 2wd or 4h with this mod. A simple search of this site should lead you to a writeup with pics on how to do it.

 

Quick primer on 4wd and differential function.

In 2wd with an open differential 100% of all availale engine torque is transfered to 1 axle. When both tires on that axle have equal traction the differential will split that power 50/50 to each tire. But when you get into a position that 1 tire has traction and 1 tire doesnt, that diff will actuall transfer 100% of the power to the wheel with NO traction. Thats where you see 1 tire spinning and 1 tire not moving.

If you have a locking diff, the differential will "lock" both sides together and split the power 50/50 between each side all the time. So even if 1 tire has traction and the other doesnt both will spin at the same speed regardless. The benefit being the wheel with traction can push the vehicle forward until the wheel without traction can catch.

When you engage 4wd the transfer case splits the engine power 50/50 between the front axle and rear axle.

In 4wd with 2 open diffs you end up with both ends runnng the same as above. If all 4 tires have traction you get 25% of all power at each tire and 4wd. If the back tires have traction and 1 front does, each back tire has 25%, the front with traction has 0 and the front without has 50%, essentially 3wd but only the back axle is doing any work.

And if you get in the spot that 1 front and 1 rear tire has traction, you see 1 tire on each end spinning, each receives 50% and 1 tire on each doing nothing and receiving 0. Essentially back to 2wd but no work being done.

The best solution is 4wd and having each diff locked. That forces the vehicle into true 4wd, all the time. Each tire will always receive 25% regardless of how much traction it has.

At some point though you will end up with all 4 spinning and even though they are all receiving power, no work is being done. At that point youll wither be really happy you have a winch and recovery gear, or someone finds your frozen body in a couple months

 

One thing I don't understand about 4wd and open diffs. If you have open diffs front and rear, why does the drive train bind up on hard surfaces? (I don't speak from experience)

 

Because the front wheels are traveling in a circle of a larger diameter than the rear, thus covering more ground, thus needing to turn a little faster than the rear, thus causing hopping and scuffing on dry pavement.