Disengaging driveshaft to front differential?

[FireFighter209]

I’ve heard there is a way to disengage it. I’ve been told the fact that mine spins when I’m accelerating, means it’s on. However I have a 4x4 which can go between 2wd and 4wd. I have it set to 2wd and it still spins? My driveshaft is extremely bad, rattling when I release the gas, I believe the rattling overtime has now caused front diff to crack in multiple places. So I’ve heard there is a way to disengage it, hopefully I was told right but I’d like to see if there are any good explanations or videos

 

[imp]

I’ve heard there is a way to disengage it. I’ve been told the fact that mine spins when I’m accelerating, means it’s on. However I have a 4x4 which can go between 2wd and 4wd. I have it set to 2wd and it still spins? My driveshaft is extremely bad, rattling when I release the gas, I believe the rattling overtime has now caused front diff to crack in multiple places. So I’ve heard there is a way to disengage it, hopefully I was told right but I’d like to see if there are any good explanations or videos

@FireFighter209

Start at the Transfer Case which turns the Front Driveshaft. That turns the Differential Input Shaft, which turns each front axle shaft. Early 4X4s had manual disengagements called "locking hubs" located on the front wheels. Ford did away with those, but still desired disengagement so installed a vacuum-operated disengagement mechanism right in the Differential Housing. Looks like this:

It's purpose is to allow the front driveshaft to "free-wheel", not being driven by either the Transfer Case (in 4WD), or by the turning front axles (in 2WD) while Coasting.

You can physically remove the front driveshaft altogether if the vacuum mechanism is faulty (thereby having 2WD only), but disengaging it at the differential itself makes little sense if the unit itself is faulty. imp

 

[CDW6212R]

Ditto. Your 2WD/4WD switch doesn't stop the parts from spinning. It just disconnects the front drive parts from the transfer case.

If you think there's something wrong with the drive shaft, you ought to remove it and have it checked and repaired. I think those are straightforward u-joint parts to replace in that.

If there is anything wrong with the front diff, you need to fix that before too long. Don't let it run dry of grease, that will fully kill it. With the drive shaft out, see how the differential feels by rotating the pinion, move that side to side and see what play is there.

 

[96eb96]

I’ve heard there is a way to disengage it. I’ve been told the fact that mine spins when I’m accelerating, means it’s on. However I have a 4x4 which can go between 2wd and 4wd. I have it set to 2wd and it still spins? My driveshaft is extremely bad, rattling when I release the gas, I believe the rattling overtime has now caused front diff to crack in multiple places. So I’ve heard there is a way to disengage it, hopefully I was told right but I’d like to see if there are any good explanations or videos

You can certainly remove the DS on a control trac system (not the v8 awd, because it could creep in park!)
Being in CA there are probably tons of front axles in Pick and Pulls from trucks without rust. It isn't hard to replace DIY or you can find a shop. You have to know your Axle ratio from the door code. You would have to find a 95-96 truck. 97 is different.