Shifting into 4WD W/manual hubs??

M

mldave

New Member
On my 86 Toyota truck with manual hubs,after locking the manual hubs can I shift from 2Hi to 4Hi at any safe speed after easing off the accelerator?Say,25-35 MPH?Any step by step guide to shifting to/from 4Wd,any tips?...thanks.
 
If it came with manual hubs from the factory, that means it does not have the center-disconnect axle....so yes, you can shift from 2hi to 4hi or back as long as the hubs are locked. (and you aren't turning, or slipping tires, etc)

The hubs locked in will mean the whole drivetrain is spinning at the same rate, so there will be no load on the Tcase gears to prevent you from shifting in/out of 4wd.

4lo is the exception, you'll need to be basically stopped before shifting from hi to lo or back.
 
Yup, in fact having the hubs locked is essential to being able to shift from 2HI to 4HI on the fly. The act of having the hubs locked in 2HI synchronizes the front T-case output with the rear output.

Throwing the T-case lever from 2HI to 4HI without the hubs locked results is nasty gear grinding because you are trying to bring a stationary front output shaft up to the rear outputs speed.

You've got the right idea of easing off the gas, pushing in the clutch also helps.

4Lo requires stopping or coasting with the clutch disengaged while rolling down from 5mph.

EDIT: Damn Carl, you are too fast!
 
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Can I ask a question regarding this? Is driving on 2hi with the manual hubs locked in cause any unnecessary wear on parts at all? Or is it alright to leave them locked in for days without using 4hi?
 
Hiro said:
Can I ask a question regarding this? Is driving on 2hi with the manual hubs locked in cause any unnecessary wear on parts at all? Or is it alright to leave them locked in for days without using 4hi?
Click to expand...

You're spinning a lot of extra parts so mileage goes down. I wouldn't go days with the hubs locked and not needing them. If I was going to work and needed 4wd for a while and then the roads cleared up and I hit dry pavement I would probably just put it in 2wd and leave the hubs locked until it was convenient* to unlock the hubs.

*disclaimer lockers, age of parts, etc impact that time period before unlocking the hubs
 
Spork said:
You're spinning a lot of extra parts so mileage goes down. I wouldn't go days with the hubs locked and not needing them. If I was going to work and needed 4wd for a while and then the roads cleared up and I hit dry pavement I would probably just put it in 2wd and leave the hubs locked until it was convenient* to unlock the hubs.

*disclaimer lockers, age of parts, etc impact that time period before unlocking the hubs
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x2.

That being said, some of the 4runners and tacomas have hubs that are essentially "locked" all the time.
 
sixstringsteve said:
x2.

That being said, some of the 4runners and tacomas have hubs that are essentially "locked" all the time.
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Alot of toyota's have ADD which is a axle shaft disconnect that is vaccum operated which is why they are locked all the time but that means only the axle shafts are turning when in 2hi not the diff or drive line in front:greg:
 
My 4runner is an 88, would that be vacuum operated as well? The only thing I noticed between having the hubs locked or not while in 2Hi was that it's easier to steer the truck when not locked. But I had the hubs locked for a good week and I figured that way I wouldnt need to get out and lock them when I had to switch over to 4Hi, but I thought I might be causing wear on the parts so I unlocked 'em.
 
if you have manual hubs (a dial that let's you switch them to "locked and unlocked"), then it's not vacuum operated.
 
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