Some very basic 4x4 questions.

[TorontoGuy]

So here's just a couple questions that I've had and haven't really been able to answer despite reading countless threads, the owners manual, and the supplementary 4x4 guide that was included with the original owners manual Be easy on me as this is my first 4x4 vehicle

1) When driving along in 2wd, is anything in the front end spinning? Such as front driveshaft or differential? I was always under the assumption that if you weren't in 4x4 nothing in terms of the front driveline was spinning (aside from the wheels and tires )

2) When I engage 4x4, do I get the added traction benefits immediately or do I have to wait for the auto hubs to engage? When do they engage?

3) Once the auto hubs have engaged, the only way to disengage them is to drive in reverse a short distance, correct?

That's all I can really think of now, but I'm sure I'll come up with more in the future, and hopefully my basic questions can help out another new owner in the future.

Cheers!

 

[RangerX]

1. No, nothing spins on your vehicle.
2. No traction till the hubs engage, but it's pretty instant. Maybe it takes a foot or so of travel, but I'm just guessing.
3. Yes, driving in reverse disengages, but only if you've taken it out of 4wd. You can back up in 4wd and it won't disengage.

 

[awood]

All the above is true if you don't have anything broken in the auto hubs, or the auto hubs are not over-packed with grease. From my experience, too much grease in the auto hubs seems to be the biggest problem. A thin layer over everything is all you need.

You can engage 4WD (4-HIGH) by either pushing the button while stopped in neutral (my preferred method) or while driving - I think it was more than 5 mph but less than 25 mph.

Going into "4 Low" you must be stopped and in neutral, then hit the button.

As far as I could tell, the hubs engaged the instant I hit the button.

 

[TorontoGuy]

Awesome guys! Thanks a lot

I'm sure I'll have more questions in the future

 

[Tony H]

Awesome guys! Thanks a lot

I'm sure I'll have more questions in the future

The front Hubs/axles and driveshaft do not unlock on all 4WD vehicles anymore. in fact many Dodges went back to the 1940's where their Front diff and Driveshaft still spins/ Only the Transfer case disengages 4WD . Terrible gas mileage and lots of wear and tear on parts that aren't working.

Chevy Blazers and larger disengage at the Differential BUT the half axles spin all the time. Bad gas mileage.

 

[429CJ-3X2]

You can engage 4WD (4-HIGH) by either pushing the button while stopped in neutral (my preferred method) or while driving - I think it was more than 5 mph but less than 25 mph.

I prefer to engage 4WD while stopped just to be on the safe side, but the owner's manual says you should not engage 4WD while accelerating. When I shift into 4WD on the go I lift my foot off the gas and push the 4WD High button, give it a second or 2 to engage, and then continue to drive normally. I'm usually at 35mph or less.

Must be stopped and in neutral to engage 4WD Low as stated above.

 

[DeRocha]

1) When driving along in 2wd, is anything in the front end spinning? Such as front driveshaft or differential? I was always under the assumption that if you weren't in 4x4 nothing in terms of the front driveline was spinning (aside from the wheels and tires )

The front drive shaft, differential, and axle shafts do not rotate in 2WD (UNLESS the HUBs are locked). If the HUBS are locked the front driveline components will rotate in 2WD or 4WD

2) When I engage 4x4, do I get the added traction benefits immediately or do I have to wait for the auto hubs to engage? When do they engage?
Its pretty instant unless you have a broken part.

3) Once the auto hubs have engaged, the only way to disengage them is to drive in reverse a short distance, correct?
You must disengage 4x4 and go into 2WD. You then must reverse direction for about 15 ft to cause the autohubs to unlock. If you were in Drive you'd need to back up for 15 ft. If you were in in Reverse you'd need to drive forward 15 ft.

More on Automatic HUB engagement:
When you engage 4x4 the front drive shaft will spin and send power to the diff and then to the axle shafts.. The axle shafts will begin rotating within each autohub; after a few revolutions the engagement cam will have idle up within the autohub and caused the autohub to lock. Once this occurs on both hubs the wheel with the least traction (open diff) will get power and begin to rotate.

Let the above sink in for a minute.. If you try to free a vehicle by quickly going from Forward to reverse you can easily blow an auto hub.. When you reverse direction the axle shaft obviously spins in the opposite direction causing the auto hub to UNLOCK and then LOCK in the new direction.. Under low power this isn't a big deal, but if you're on the gas heavy it can definitely damage the hub... Manual hubs are either locked or open, as such they are unaffected by rocking a vehicle in the manor above.

 

[429CJ-3X2]

More on Automatic HUB engagement:
When you engage 4x4 the front drive shaft will spin and send power to the diff and then to the axle shafts.. The axle shafts will begin rotating within each autohub; after a few revolutions the engagement cam will have idle up within the autohub and caused the autohub to lock. Once this occurs on both hubs the wheel with the least traction will get power and begin to rotate.

Let the above sink in for a minute.. If you try to free a vehicle by quickly going from Forward to reverse you can easily blow an auto hub.. When you reverse direction the axle shaft obviously spins in the opposite direction causing the auto hub to UNLOCK and then LOCK in the new direction.. Under low power this isn't a big deal, but if you're on the gas heavy it can definitely damage the hub... Manual hubs are either locked or open, as such they are unaffected by rocking a vehicle in the manor above.

Good info. I hadn't considered that. My '94 has manual hubs and I rarely get stuck since I don't off-road, but good to know!

 

[Kiliona]

If there is any wheeling in your future I'd highly suggest getting manual hubs due to the phenomenon DeRocha explained where "rocking" the car back and forth can blow up auto hubs. Manual hubs are much tougher, and there's never any question of "have my hubs engaged/disengaged yet"