Exercise your 4H/4L

That's pretty much it. They're either locked or they're not. Toyota locking axles are open when not locked. Only one company makes a LSD/Locker but it's an aftermarket unit.

 

Ah yes, limited slip differential. That’s the piece that was eluding my brain at the moment.

 

There used to be a 4wd Simplified interactive page by Toyota but they took it down. It would explain the differences of everything and let you "lock axles" on a virtual truck to get through obstacles.

 

All that does is use clutches to transfer some power to the other wheel but it's limited on what it can do. Toyota got cheap and eliminated it for brake actuated limited slip which slows down the wheel with no traction so the diff transfers power to the other wheel.

 

Lever ftw

 

I probably could have been more specific here. Obviously with the front and rear differential being open, all four tires aren't actually trying to spin at the same speed.

What I should have said is that the front and rear axles are trying to spin at the same speed. Those of us who have part-time four-wheel drive do not have a center differential. Our transfer case is either locked, or disengaged.

So, when we're in 4HI or 4LO, the front axle is turning at the same speed as the rear. This seems potentially dangerous to me, as it could cause understeer, which could lead to an accident.

 

Yes, and no. We still have an actuator in the front differential that could fail if not exercised.

But, I do love the lever.

 

thx folks. i've never needed 4Lo, so my experience/understanding in this area is limited. plus all my recent vehicles have been AWD, which meant i didn't need to think about that stuff anymore.

 

4LO comes in super handy in rocky areas and steep inclines and descents. Sometimes I use it just to get the RPM's up in areas where I'm creeping along slowly. It's also nice if you use your 4Runner to pull stumps.

 

I’ve used 4L to descend steep trails and it does work nicely.

I have also tried the downhill accent mode, but the ABS makes a terrible racket. I’ve found that being in 4L and 1st gear really slows the decent without having to use the downhill accent mode.

 

I was going to mention about using S1 but you beat me to it!

I definitely prefer 4LO and S1 over the automated descent. I believe Crawl works the same on descents and I'm just not a big fan.

 

In high school many years ago, I had a hot rod and had several rear differentials. One had 4-10 gears and I had the spiders shimmed so it acted like a posi-trac. I couldn’t locate or afford a real one. Tires would chirp when turning.

It worked great until it literally hand grenaded. Pieces of gear tooth came through the differential housing.

 

Ouch! Probably fun while it lasted, though.

 

Yep, when you’re a teenager with no money, you have to improvise.

 

Lol, sounds like something I would have done. Your approach to posi I think is also known a “Lincoln Locker”. As in, you use a lincoln welder to permanently lock the differential. That always gives me a chuckle

 

Exactly, at that time the cheapest way to get speed was regear the diff and add NOS.

Yes, I blew my engine up too!

 

I just exercised my 4H/L in the 4Runner.

Fun fact, I didn’t need to hold the brake for 4L to engage.

 

wait, does that mean it works now? or that the brake didnt help…

 

Not going to lie, if you’re using 4 hi in situations where understeer can be an issue, you probably shouldn’t be using it and/or going that fast.

The only time I use it on the road is if it’s snowy AND icy.

 

Don't forget those diff lockers.

 

No, Sequoia is still jacked up.

I took my 4Runner out for a spin.

 

Your right!

But I don’t have any.

 

The only time I feel "binding" in the system is when making a full-lock slow turn in a parking lot. Not at any speeds that matter.

 

I'm sure this is a stupid question, but I bet others have it, so I'll ask it anyway. It's rare that I need 4H (truly, maybe 5 times a year to drive 100 yard across a muddy site, or a snow storm or two when I travel north), and NEVER that I need 4Lo. Advice on how to exercise the system when all you've got handy is paved roads?

 

Find any straight road, paved or not, and lock it in for a bit. Shift out when you need to turn. For low you will need an empty road or parking lot since the speeds are very slow.

 

How long should I drive it in low? (and thanks!)

 

There's no real answer for that. You are mostly exercising the shift motor (if you have a knob unless AWD) and the ADD actuator (all except AWD). Part of the case internals are always turning as you drive and everything turns in any 4wd mode.

 

Realistically 2-3 turns to wet the gears is enough.

 

There's usually a pump in the case that distributes lube. The chain will pick up lube and splash everything when you engage 4wd.

 

To add to what @whippersnapper02 and @LandCruiser have said;

You can probably just roll back and forth 10 feet or so. It might be good to go back and forth from 4hi to 4lo, and back to 2wd a few times. These thing seem to work better the more often you use them.