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Shifting questions - 1990 4x4

To the experienced, this will seem a bit odd, but I'm a bit new to the

4x4 thing and I've been given conflicting information about this so I'm looking for experienced advice..... ;-)

I have a 1990 Toyota truck 4x4 5-speed 22RE engine.

Can I shift into LOW (4-wheel) range and drive the truck without locking the front hubs without doing any damage? This might be when I want the very slow speed but don't need the actual drive from the front wheels. I know I won't be in actual 4-wheel drive, but what I want is the low speed that LOW range gives me.

Also, do I need to take the hubs off LOCK if I shift out of 4-wheel drive in the cab, if it's just for a short distance?

I guess the question is if you shift into 4-wheel drive do you always have to trot outside and lock the hubs and vice-versa? Is there a potential for drive-train damage here if you do the wrong thing?

Dave

Reply to
davemcc
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I know you can shift out of 4 and leave the hubs locked for short distances. All it does is spin the front drive train resulting in a bit more wear over time.

-Dru

Reply to
DruG

Yes, you can use 4 low without the hubs locked. In effect, this gives you

2 wheel low. I use it for the reasons you stated above.

You could keep the hubs locked all the time if you wanted. In fact the owners manual says you should lock them in once a month to keep the front axle parts lubed. Unlocking the hubs when in 2 wheel drive gives slightly better gas mileage and saves wear on you front axle and driveshaft.

If you know you will need 4 wheel drive you can lock the hubs in advance and just shift the transfer case when 4 wheel drive is needed. As an example, I live in the northeast. When winter time comes I will lock my hubs in and when I need 4 wheel drive I just need to shift the transfer case whithout getting out of the truck, when 4 wheel drive is not needed I just shift the transfer case back to 2 wheel drive and keep the hubs locked. I sometimes leave the hubs locked in for months.

Is there a

Yes there is. You do not want to use 4 wheel drive on a hard surface, such as a paved road. When you shift the transfer case into 4 wheel drive the transfer case locks the front and rear driveshafts together so that the the front and rear wheels turn at the same speed. When you drive the truck and make a turn all, 4 wheels turn at a slightly different speed, but 4 wheel drive won't allow this because the front and rear wheels are forced to turn at the same speed because they are locked together. This causes the drivetrain to bind up. When you drive on a slippery surface such as mud, snow, gravel, dirt, etc... the wheels will be able to spin, which will allow them to turn at different speeds and does not cause the drivetrain to bind up.

Reply to
Mike

IF (and I think it is true) that your truck has manual hubs -- where you have to get out and physically turn a dial to lock the hubs to the axle -- then you are correct, you can select 4LO and have 2WD in LO range. Obviously, the rear tires will be driving your truck.

No, you do not need to get out and unlock the front hubs after shifting out of 4WD. The front tires will be turning the front drive train, and this will consume extra fuel and create added gear wear in the differentials, but I've had my front hubs locked in 2WD for a very long time.

Reply to
Jeff Strickland

What Mike said.

Reply to
Jeff Strickland

I used to do it all the time, lauching the boat etc low speeds on the wet ramp was great.

Never had any issues and no real wear issues resulted.

Reply to
Scotty

I can think of two minor issues when driving in "L2".

AFAIK there is no kind of automatic synchronization (synchromesh) between the front axle and the output of the low-gearbox. This means that if the car is put in H4 while it is moving, a rotating axle meet a stationary axle.. So if the front hubs are not locked, you should only change to H4 when the car is at stand-still. Of course, when the hubs are locked, the rotation of the front and rear axles will always be directly or indirectly synchronized, which is why the H2H4 transition can be made at any (practical) speed.

The other point is a bit more subtle: When in L4 you have an additional

2:1 gear - this halves the speed-of-revolution, but doubles the torque. This is not a problem when the front hubs are locked in, as the doubled torque is distributed across two set of axles. Of course, when the front hubs are not locked, in the rear axle experiences the doubled torque. I don't know for a fact if this is a problem, but I would be careful when driving in "L2" (i.e. no off-roading or trailer-pulling).

However, this is all theoretical and I may be wrong ;).

Reply to
David

The gear ratio in LO Range is the same whether the front hubs are locked or not. There is no problem at all, if one wants lo speed, high torque, and 2WD with only the rear wheels getting power.

My Jeep has the ability to engage 2LO in FWD only, the OP wants his 2LO to be RWD. No problem at all. Offroading and trailer pulling is the most common time when 2LO will be desired. No problem.

Reply to
Jeff Strickland

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