4x4 Maintenance

I just have some questions about 4WD maintenance. Most of my driving will be on road in dry conditions.

How often, distance, speeds. Any info would be greatly appreciated.

 

Did you read your owners manual? It’s in there.

 

Once a month find a dirt road or some soft shoulder and get it in 4wd to keep things lubed and functioning.

As above read the manual, or the cue card on your Sun visor.

 

I just pop mine into 4wd once a month or when I’m driving out of my neighborhood in the am. It’s a straight shot.

 

I change the filter in my Brita water thingy on the first of every month. It's on the calendar on the fridge. In the summer, I know that means to take the truck out and run it for a bit in 4xhigh and 4xlow and make sure the locker still works.

As of the last couple days I haven't taken my truck out of 4xhigh so I think I'm ok to carry it over a while.


Seriously though. Once a month, Put the truck in 4high and drive it 100 yards. Put it in 4 low and back up 100 yards. That's all the drive train needs to keep everything running smoothly.

Alternatively, go use your truck offroad like it was built to do. You'll use the transfer case and have some memories to take home.

 

OP, you should read between the lines. What the manual really mean is, you should take the truck off-roading once a month.

 

swap to an FJ case and no maintenance needed, those electronic actuators are junk junk junk...

 

FWIW & YMMV -- I have had no problems exercising the 4WD HI transfer case at speed (55-60mph) on clean dry pavement with my 2014 V6 6spd MT. So long as the vehicle is travelling in a straight line, there is no difference in wheel rotation speed and hence no wind-up tension builds up in the drivetrain.

I live in an area where it's not easy to accumulate the Toyota-recommended 10 miles per month in 4WD off-road, so I sometimes do it (carefully) on-road, on long straight sections of county road or highway.

The Toyota owner's manual explicitly allows changing into 4HI at speeds up to 62mph. (Beyond 62 mph the ECU locks out the shift-into-4HI function, but it will allow shifting out of 4HI, back to 2HI.)

(NB: the owner's manual is actually a little bit wrong in some of the wording below. You don't turn the "front wheel drive switch" fully clockwise, as this would try to select 4LO mode... You turn it one notch (detent) clockwise from 2HI to 4HI...)

(NB 2: If using this high-speed dry-pavement 4HI exercise method, PAY ATTENTION and do not forget to switch back to normal 2HI mode before any significant** curves / turns in the road! It could be dangerous (degraded control of vehicle,) destructive to the drivetrain, or both to be moving at high speed in 4HI while turning on a normal dry asphalt road surface.)

(** significant = more accumulated turning angle and/or turn duration than a single, normal highway lane change.)




NB for others who are driving stock Tacos & want to try this I suggest you start at far lower speeds, like <15 mph, and work your way up from there listening carefully for any abnormal sounds, vibrations, etc. When I do it there is usually no sound or sensation at all, going in, or out, of 4WD HI at higher speeds.

If your taco is signficantly modified -- especially if you happen to have different-diameter front & rear tires, or a lot of lift, or other known problems with driveline vibration at speed -- just find dirt roads or a dirt parking lot somewhere instead.

Also, the Toyota owner's manual explicitly cautions against using 4HI on paved roads. The reason (potential for 4WD bind-up) is hinted at in the 3rd sentence below, "..increased tire wear.." (because some wheels are trying to spin at different speeds through a turn than others but being bound up by 4WD bind-up.) As long as the vehicle is not turning at all, straight-line travel in 4WD HI should pose no problem on dry pavement at any reasonable speed.



Reasons to "exercise" the 4WD system periodically: Keeps transfer case and front diff gears & seals fully lubricated, and just as important, exercises the little match-stick-sized metal wiper-arm electrical position-indicator and limit-switch contactors inside the transfer case & front diff electrical actuators, helping to keep their electrical conductivity adequate for purpose.

Since the transfer case is all one large chamber inside, with the 4HI and 4LO gears sharing the same oil bath, I don't think there's any specific reason to engage 4LO separately from 4HI. The only reason to do 4LO with rear E-locker (electrical-actuated rear diff locker, for those Tacos equipped with one) would be to exercise the electrical actuator / contacts in that rear diff actuator unit. 4LO of course has different & more stringent requirements for activation/deactivation (vehicle must be stopped) and much lower max-speed limits. (About 28-30 mph is as high as I've ever cared to push 4LO, in 6th gear on my manual transmission.)

 

I am in the habit of exercising 4x4 at the start of some rainy days on straight roads. I am already mindful of the roads being slick after a first rain, so that is my reminder to put it in 4x4.

 

Stealerships need to eat well, so it seems all manufacturers leave them some bread for later. After the warranty is up, I'll use a reputable independent shop for service so they stay lean.

But nevertheless, stealerships still matter.

 

yes it’s definitely an easy target for a customer. Just google “Tacoma 4x4 light blinking” or something similar and you’ll get more threads than horn pub

 

Just posting this here as a bread-crumb in case someone is trolling through this thread looking for "how to fix my tacoma 4WD".

Unfortunately it appplies only to 2nd gens, 2005 through 2015 specifically. There is a lot of pinout-level fine detail that probably doesn't work word-for-word with 3rd gens. Maybe someone with time & tech chops will do an adaptation or update of OP's original post in the thread, for 3rd gens:

https://www.tacomaworld.com/threads/4wd-system-operation-help-thread.742420/

If there's already an equivalent-quality thread for 3rd gens, please reply & share it.

 

Update: it looks like it's possible that the 2nd gen & 3rd gen 4WD subsystems are very close or even identical in design, pinouts, etc.

If this member's post is accurate & he has installed a 2LO Module --- which was designed for 2005-2015 2nd gens -- directly into his 3rd gen, without any other modifications, it seems to suggest the 4WD subsystems may indeed be pinout-compatible. For the 2LO module to work it has to go through delicate dance of signaling & timing. If Toyota had made any major changes to 4WD signalling or logic/timing in 3rd gen, the 2nd-gen-designed 2LO module would not work....

https://www.tacomaworld.com/threads/those-with-manual-transmission-why.692134/page-85#post-28230535