2007 H3 285,000 miles.

Front driveshaft CV joint went out, so while parts were on order I took the front drive shaft out so I could drive it. Tonight while driving home the transfer case slipped OUT of 4 HI lock, and thus the truck wouldn't move. I pushed the truck a short ways, and the transfer case slipped back into lock, so I could get home.

I read a lot about these transfer cases getting STUCK in 4 HI lock, but never slipping out. Is this a symptom of a broken fork? In the mean-time I have the CV joint and will replace everything tomorrow and plan on driving it, as long as there would be no damage from driving with a broken fork (assuming that's what this is).

Am I assuming correctly?

 

I assume that you are assuming correctly.

When was the last time the trans fluid and filter were changed and is it still the original trans that has never been rebuilt?

 

I got it at 160,000, so at least original since then. Fluids have been changed very regularly on everything (trans, transfer, diffs). Colors all have looked good, and no burnt smell.

The problem is definitely the transfer case not staying in 4 lock. I drove it yesterday no issues, until coming home (without the front drive shaft). Transmission shifts well, with no slipping.
I'm just curious if the shift fork problem can cause the reverse of what most people experience. In my case it is slipping OUT. But I'm not sure how easily a person would be able to tell if their transfer case really wasn't locked (unless you are missing the front drive shaft, like me at the moment).

 

Most people do not drive around without the front drive shaft in 4hi lock.

The shift fork rides in a groove in a collar and just pushes over the lock collar to your selected position. When it wears out, the fork will not stay in the groove, it can slip out of the groove and allow the collar to wander and/or will not move it upon command. Most of the time it gets stuck in whatever position it was last shifted to, but not always every time.

 

Totally agree about the drive shaft , but I was in a situation and needed a way to drive it while parts were coming. Parts are here, and drive shaft is going in now. It was only driven that way 1 day.

I ordered a shift fork, so I'll get that out and changed when it warms up a bit (-11 is no fun when you are taking out a driveshaft), though it will probably be this spring, knowing I'm not stuck IN 4 lock.

Thanks for your feedback.