Sheared CV axle!

[Steventruck]

I was my way to go hunting Saturday morning so we packed up the truck and hit the road at 4:30am. Twenty minutes later, we were cruising along at 60mph on a paved state highway with everything sounding and feeling normal. Then, all of a sudden, there was a bang, followed by vibration and metal-to-metal banging/rattling. I pulled over immediately.

The right front CV axle was sheered off right behind the wheel bearing. The rest of it was still in the wheel bearing with the but still on... but the plastic cap was knocked off (we had to walk back and find it). We called AAA and had to wait an hour for the truck. So while we were waiting, we tried to diagnose it.

• When the truck is rolled forward in 2WD, the broken shaft spins back-wards.
• When the truck is rolled back-wards in 2WD, the broken shaft spins forward.
• When the truck is rolled forward in 4WD, there was resistance (the truck wanted to stall as I slowly let out the clutch).
• We turned off the truck and crawled under the truck and tried to spin the front drive shaft (in 2WD), it wouldn't budge.
• There was no grease/oil leaking out out of anything.
• I think the only damage was the broken shaft and the wheel bearing (as I drove the 200' from 60 to 0.

It appears that I had two problem that occurred simultaneously:
1- The pinion is seized up or for some reason will not turn.
2- The the thing that engages the RH axle engaged on it's own.
These to problems on there own are tolerable, but at the same time is catastrophic.

This truck is a manual trans ZR2, but the drivetrain should be the same as the crewcab except I have a iron front diff carrier and you guys have aluminum.

What should I look for? I'd rather not buy a new front pig, is that my only option? The two broken mentioned above are less than two months old so they will be replaced under warranty.

Thanks in advance.

Steve

[HenryJ]

Sounds like you are going to have to tear it all down. Dropping the front driveshaft and checking the transfercase is a given.
I am a little suspicious of the seized pinion bearing. I have seen some get really bad and not seize. I would suspect a broken ring , pinion or piece wedged. That would seize the pinion.

The front axle should not be able to engage on its own. The default is disengaged. I would look to the transfercase switch for a failure. Maybe it did not disengage from the last use?

Running high speed on pavement with the front axle engaged, or the transfercase engaged could easily destroy the front end and or the transfercase.

Fortunately the front axle assembly is not too hard to remove.
Tear it all down and let us know what you find.
Muslhed is a good one to walk you through the rebuild. He has been through them and studied them for quite a while now.

[Steventruck]

I disconnected the front U-bolt and was able to turn the shaft easily (so the transfer case is okay).

I'm beginning to think this truck is possessed!

[purduecrew]

does this say anything for the strength of cast iron front diffs over aluminum? I know I know, its been debated into the ground