front drive shaft

[nat88toy]

got a question for you rover guys...
my friends was driving his 2001 disco when he started hearing some binding in the front end he was a mile from home so he kept his seed at 20mph. He was about 100 yards from his house when he heard a pop front drive shaft let go at the double cardian joint, at this point he shut the truck off an called me, came over with my tool bag and pulled the front shaft or what was left of it off figured we could drive it the 100 yards to his drive way with just the rear wheels put the truck in gear and nothing just reves up like its in nutral
so my question is do you need that front shaft in for it to get into gear or did he mess up his transfer case

thanks, nat

 

[Oilburner]

It has a center diff in the T case so it is not going to move unless you lock the diff - Some DIIs have a shift lever that locks the diff lock, some do not. See if you can lock the center diff by moving the hi-lo lever sideways (it should say "lock"), if not you might have to get it towed, I am not sure if you can manually engage it from underneath (the engagement mechanism is on top of the front nose cone of the C case, where the front driveshaft bolts in, it's a small shaft sticking straight up).

 

[overlander]

Has it moved yet? This is where that center diff and diff lock comes in to play. without the center diff locked, it is going to transmit all the power to the front end without the shaft (without resistance) just like when one wheel on an axle gets in mud (or air) while the other has traction, and the open diff transmits power to the tire with no traction. You would need to lock the diff, so that power can be transmitted equally (regardless of resistance) to front and rear shafts. I can' remember what years the early disco II's didn't have the center locking diff (even thought the transfer case had the capability), but I think your buddy probably doesn't have one.

As for the shaft, i'm surprised a double cardian joint failed. But when a drive shaft does fail (due to a failed U-joint), usually there is a good early warning of abnormal localized vibration (from the play in the cups where the rollers are shot) well before it goes. A big POP sure sounds to me like an axle breaking, which on a road could be caused by a wheel bearing seizing (ask me how I know ), and then trying to move the vehicle while the bearing is seized. Let us know what you find out. If both front wheels can turn when lifted off the ground, and no grinding from the diff, then it sounds to me like it was a very unusual no-warning drive shaft failure, which is much better than any other failure possibility I can think of for that set of symptoms.

J-L beat me to it.

 

[Oilburner]

Overlander, back when I worked for a LR dealer (2003-2004) DIIs had lots of problems with DC failure - I have seen many of these fail and take out the transmission casing. It would be wise to have the joint rebuilt with greasable U-joints before it explodes if you have a DII - The double cardan joint is a standard Spicer part, so any heavy truck driveline shop should be able to set it up. And, you can drive around in 2wd for a while, until you get it reinstalled. Nothing like destroying a ZF trans to ruin your day (or adventure).

Edit: The ones I have seen blow were always at fairly high speed. I don't think it's a loading issue, as much as it is that the centering ball wears, which makes the shaft go all wobbly, and finally explodes due to the stresses. A driveshaft letting go at 60+ mph is nasty.

 

[UofRichmondRover]

99-00s and some 2001s have the center diff lock, but it is not hooked up. check for a knub on top of the t-case.
2004s have the cdl and can be engaged from the factory. Just move it from right to left.

If he has a DII that has a center diff lock other than an 04, you can search around on discoweb.org to find out how to hook it up several different ways. Its a great mod especially if he plans on using it offroad. Although, at this point its just easier to tow unless he has a 2004.

With the cdl locked you can drive without missing a shaft, front or rear. Judging from the fact that when you removed the drive shaft the truck revved in gear without an additional clunks I bet he didn't do any other damage.

 

[nat88toy]

ahh that center diff makes a lot of sense why it still was not moving he is going to get the drive shaft fixed today so i can get it back in the truck hopefully all is well then

a side note.. after i took off the drive shaft i towed it back to his house with my 4runner, with his truck in neutral with no abnormal noise

thanks for your help guys, i have a feeling its not as bad as i thought it was now i will keep you posted
-nat

 

[overlander]

If it can be towed without issue, then sounds like your doing pretty well. best of luck. 110's have greasables front/rear, but my wife has an 03' disco that I'll have to consider oilburner's mod for.