Question about using the 4WD...

boynton6spd · June 14, 2017

Manual says to NOT dirve in 4WD on dry pavement or damage may occur...

How is this so?

New to 4WD and trying to learn...

gearheadesw · June 14, 2017

If there is absolutely no slip, ie rain or snow, binding can occur in the transfer case. It's turning on dry pavement that is not good.

newdude · June 14, 2017

Correct on the binding. Lots of harsh wheel hop on turns can be produced which could potentially lead to front axle component damage.

aseibel · June 14, 2017

You should only use 4wd when you are in off-road situations where traction is low.

Ice, snow, mud, sand, etc.

You can actually drive forever in a straight line in 4wd, (still shouldn't) but the second you try to turn the wheel on concrete, you'll know why you should take it out of 4wd.

boynton6spd · June 14, 2017

Thanks for the replies!

Offcamber · June 14, 2017

This is the difference between AWD and 4WD.. AWD systems are more advances and apply power to the wheels that are slipping. 4WD applies power to the front and year differentials equally. When there is a difference in wheel speed but no slipping ( like when you turn on dry pavement) the system will bind.

revrnd · June 14, 2017

Do the AWD transfer case have an internal differential?

I'm thinking the OLD full-time cases did since they 'drove' the front axle @ all times. 'Locking' the case, locked the different to split power 50/50 to the front & rear axles.

Offcamber · June 15, 2017

Di

Do the AWD transfer case have an internal differential?

I'm thinking the OLD full-time cases did since they 'drove' the front axle @ all times. 'Locking' the case, locked the different to split power 50/50 to the front & rear axles.

Different systems use different designs. Some have a viscous coupler, some use planetary gears, others have a clutch plate system much of it is computer controlled tied directly to the ABS and stability control systems. Not all AWD is created equally Jeep, Audi and Subaru have very good systems IMO. Do not be confused with the "Automatic" setting and the 1500 trucks it is NOT AWD...This system should not be used on dry pavement either.

sdeeter19555 · June 15, 2017

Correct on the binding. Lots of harsh wheel hop on turns can be produced which could potentially lead to front axle component damage.

And transfercase chain stretch...

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sdeeter19555 · June 15, 2017

Do the AWD transfer case have an internal differential?

I'm thinking the OLD full-time cases did since they 'drove' the front axle @ all times. 'Locking' the case, locked the different to split power 50/50 to the front & rear axles.

The old NP203 had a differential inside that you could "lock". The NP203 had an external gear reduction on it for low range, so you could have low and high on dry pavement.

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revrnd · June 20, 2017

The old NP203 had a differential inside that you could "lock". The NP203 had an external gear reduction on it for low range, so you could have low and high on dry pavement.

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The NP203 was the case I was thinking of.

A co-worker had bought a late 70s/early 80s Blazer (new to 4x4s) & was concerned about the front axle 'hopping' when turning. I asked him if he had the transfer case in Hi, not Hi Loc. He said it was in Hi. I copied the shifter adjustment procedure from the service manual (I had an '82 K15) & gave it to him. He got back to me in a few days & told me the linkage needed adjustment. Once he was done, everything was good.

paauto · June 20, 2017

Do we need to back the truck up 10 feet or so after going from 4 to 2 to disengage the hubs?

SouthernSilveradoGuy85 · June 20, 2017

Do we need to back the truck up 10 feet or so after going from 4 to 2 to disengage the hubs?

I didn't have to in either my '14 or old '98. Didn't know you ever had to do that rather it was auto locking hubs or the manual hubs that you turn yourself.

kstruckcountry · June 20, 2017

Do we need to back the truck up 10 feet or so after going from 4 to 2 to disengage the hubs?

Nope, there aren't any.

Here is a picture as to why 4x4 shouldn't be used on dry pavement.

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paauto · June 20, 2017

I didn't have to in either my '14 or old '98. Didn't know you ever had to do that rather it was auto locking hubs or the manual hubs that you turn yourself.

In my '88 Bronco had to back up 10 feet after going from 4 to 2 in order to disengage the hubs and stop the front wheels from turning the front drive shaft.