Just wondering what the max speed is to engage 4x4 hi, preferrably for a 1st gen explorer if that makes a difference. automatic as well if that matters.

I thought it was around 70 kph, not sure what the speed is to disengage...

first off - you need to lock the hubs from a dead roll - after that you engage upto 50mph - it is not recommended to use 4wd above 55mph (If I remember correctly)
If you fail to pre-lock the hubs you'll sheer off the pins on the hubs.

I used to have a 94 4x4 X and I remember you weren't supposed to engage the 4x4 while moving faster than 55mph. So a good rule is to try to engage it while yo uare stopped or moving slow when you know you need it, but you cna engage up to around 45-50mph and probably be fine with the components engaging with no more wear than usual.

lbrowne, just checking to see if you have manual or auto hubs. And I also beleive that TSTONE is correct about not going faster than 55mph when 4x4 is engage.

You can disengage 4x4 at any speed, if you have autohubs I would only engage 4x4 if going under 40MPH ~70kph to allow the T-case to gradually bring the front drive train up to speed with the rear. Once your front HUBs are locked you can engage 4x4 at higher speeds, but I would advise against using 4x4 at speeds above 50 mph.. If you travelling faster than 50mph you probably don't need 4x4 anyway. :eek:

45 MPH my 1988 Bronco II with the "touch drive" and BW1350 T case and auto hubs, factory owners guide says do not switch into 4x4 H after 45 MPH

I have drivin in 4x4 hi at 70+ MPH for extended periods without problems.....(snowy roads)

first off - you need to lock the hubs from a dead roll - after that you engage upto 50mph - it is not recommended to use 4wd above 55mph (If I remember correctly)
If you fail to pre-lock the hubs you'll sheer off the pins on the hubs.

I thought with auto hubs you didn't have to lock them beforehand. When you say engage from a dead roll does that mean pop the trunk in neutral and then press 4x4 - then place back in drive?

You do not get out to engage auto hubs....

I usually slow to a crawl.....or stop...might as well help it last longer.

I thought with auto hubs you didn't have to lock them beforehand. When you say engage from a dead roll does that mean pop the trunk in neutral and then press 4x4 - then place back in drive?

I believe Tstone was saying before your autohubs are locked you must only engage 4x4 at a low speed. But once your Hubs are locked you can engage and disengage 4x4 at higher speeds without placing any unnecessary stress on the hubs that occurs during initial lock up. Autohubs will remain locked until you reverse direction.

I was trying to say: according to Ford - intially you need to stop the vehicle - engage the 4wd system and roll foward(straight) appx 10ft to lock the hubs. After that you can enagage and disengage on the fly. To unlock the hubs you back up(straight) about 10ft while in 2wd mode.

Yeah what he said... :thumbsup:

All good advice. Just one thing to add (which goes along with the roll-forward advice)-- Don't ever engage 4WD when the wheels will be under any significant load as the front hubs lock up. My story--

I was in 2WD trying to go up a very steep, icy hill in the mountains. When my back wheels started to spin uselessly, I stopped completely, hit the 4WD button, then tried to go forward-- because of the steepness of the hill, this required me to get on the gas quite a bit. I heard a loud pop as my passenger-side hub broke (sheared off the very, very tiny teeth it has to hold it in the locked position.) If the autohubs are asked to move from the unlocked to locked position under any significant torque load, they will break-- this would include "rocking" the truck to get it unstuck because when switching from reverse to forward, the hubs will need to unlock and re-lock in the other direction.

To prevent this, I should have backed down the hill to a flat area where I could engage the hubs before going up.