I was having a problem with 4wd and regreased/ cleaned hubs and when I went to test operation both fronts would engage and worked good. After a while.of testing in and out of 4wd I heard a loud clunk and looked under, the front driveshaft blew apart at the weld.the u joints dont seem to be bad so im at a loss as why this snapped. It was not a clean break and the edges looked like it had to started to tear at some part in the past due to rust build upon the inside.of the shaft and torn edge. Im lookin at 2 feet of snow expected hewr tuesday, so im trying to find some answers as well as a.new shaft. Has any one every seen this happen before or know what else I should I check out. Thanks

 

Were you testing the 4x4 on dry pavement? If you were, that's terribly hard on the entire drivetrain. The front shaft must have been the weak link. Consider yourself lucky.

 

Iwas on ice covered with snow. Ifeel lucky because I was up in the mountains working all week its 4wd all the time or you go nowhere. Also it was 200 mile trip from home on the highway,2wd though on the highway.

 

In that case, it sounds like your front driveshaft may have just been cracked to begin with and it was a coincidence that it broke at that time. There's no way it could get bound up on ice and snow. Was it very rusty? I wonder if rust could have weakened it.

 

The outside was flaking off bad and the inside had rust all over it too. What gets me is that the drive shaft is hollow and its really thin overall

 

99.99.99.99% of drive shafts are hollow.

A solid shaft will twist sooner.

 

what model and year vehicle?

 

You can get a new one from Jeff's Bronco Graveyard, are you from the new England area? I am in mass and everyone is in a panic lol I am currently in Nashua NH for classes tonight and it looks like its going to start here soon.

 

So is an egg shell, yet as a unit, it is amazingly strong. A thin-walled, hollow driveshaft is extremely strong. Race cars, muscle cars, monster trucks, tractor trailers- all vehicles passing high horsepower and torque to the drivetrain, using hollow driveshafts.
It is hard to tell what caused the failure, but the driveshaft should be the first thing to break in the drivetrain system- it is the cheapest and easiest to replace, versus axles and gears.
Use www.car-parts.com to search local junk yards to find a used driveshaft. As common as the Super Duty is, a used one should be easy to come up with in a pinch.

 

The fact that you observed rust inside of the tube as you stated says to me that one of the welds did not go all the way around one of the yoke inserts when the shaft was manufactured. Water/salt etc has wicked inside of the shaft over time weakening the shaft. This is likely the root cause of the failure. Or it was simply not welded correctly from the get go which would mean a weak shaft when new. A bound up front joint or rear cardan joint (the 2 ujoint coupling) has been known to do unfavorable things upon failure.
Do you have a Fleet Pride or other drive-shaft house in your area? They will have what you need. Insist on Spicer ujoints. If you take your broken shaft to them they may be able to reuse the yoke ends if they are not bent. Then they will simply re-tube it and install new ujoints. Verify the ujoints have been greased before you install the new shaft. I use the Spicer recommended grease in a dedicated grease gun.

 

The guy at fleetpride told he couldnt get parts for this light duty of a truck? Ive got stuff from them before so I didnt get it but a internet searched showed that a ford dealer had one ,25 miles from me, in stock so 7 am I called them and got the parts guy who said he had it so I was forced to go that route. Reall kicker is that non greasable ujoints and he only would give me 10% off, of $470.if i wasnt in a hurry I would of bought greasable u joints and pressed them in before installing it but at the threat of 24" plus of snow ,and having to triple up work in anticipation of the snow I said screw it. Of course here in Ny where i am we just got 4" so I guess better prepared then sorry.

 

Those ujoints will last ok as long as they dont get wet all the time(lol rrrright) I got 80K out of my 08s before replacing them with greasable Spicers. This 11 has 40K, so far so good.

 

No-zerk u joints are stronger than greasable. The ones without a zerk are solid, not hollow like a greasable one. All u joints are greasable, just the solid ones need the cups pulled off and manually packed...not shot in with a greasegun.

 

Ranger, yes a very true statement. I run solids on race cars that launch hard for added track safety. But I prefer the greasables under my SD. I figure if I worked them hard enough to break them I'm doing something wrong for sure. Plus its a fusible link per-say. As Id rather snap a joint verses the next weakest parts up the line. I like the benefit of serviceability because Im a stickler about it. Which is the reason OEMs are going with non-greasable everything so the dummies dont have to worry about it until the joint falls apart. Plus I'm lazy and its much easier to put a shot of grease in every few weeks. Fresh grease pushes out the contamination, dirt and water.

 

I agree. Joints are a fuse in the driveline. I have greasable on my truck as well as i really dont need the strength of a solid or an Ox. I usually grease everymonth when doing service on the mowers( I own a lawn cutting service). In my offroad days I prefered to run hollow joints and keep spares onboards. better to swap one out instead of spinning an axle or shredding a drivesshaft.