NP231 T/Case problem

[ando_13]

OK need to pick your brains for possible problems with my NP231 Transfer Case.

Today I drove about 70k's at fwy speed then along a 80k/h rd for 5 mins, got a red traffic light, as I slowed to a stop I felt and heard a loud clunk sound. As I went to take off in 2H I has no drive, so slipped her into 4H and got thru the intersection and heard a clunk clunk clunk sound and pulled over. Had a look under, no obvious damage. Checked 2H again and no go, so 4H to meetup point for an SJC run. Once I'd met up with Steve and Wolfe, tried rocking it back and forwards in differenent ranges. 4H and 4L work but only front wheel drive, 2H just spins exactly like it is in Neutral.

Managed to get her home in front wheel drive, occassionally getting clunk clunk sounds as gears align/un align in the t/case.

Any ideas on what the problem is in my t/case anyone had a similar prob??

[ando_13]

Well have figured out it must have been diff due to the driveshaft spinning and the axles not turning.

All righty, just pulled the diff cover off (plenty of oil still in there), and have an interesting failure.

The locker and gears have been in the diff for about 3 years.

The ring gear has sheared all retaining bolts (that hold it to the carrier/locker), and thus is spinning freely when the pinion turns it.

So firstly how do I go about rebolting the ring back onto the carrer, can I do it with it still in veh, or will the centre need to be removed, thus having to re-set the pinion etc etc.

What would cause the bolts to shear off? Can't be an install type prob (ie: didn't tighten bolts up!) for years!

How can I prevent it from re-occurring?

http://users.tpg.com.au/andosam/images/image626_sm.jpg

http://users.tpg.com.au/andosam/images/image628_sm.jpg

http://users.tpg.com.au/andosam/images/image629_sm.jpg

The bottom pic shows the left overs of a bolt that has been mangled, sitting on the bottom right lip.

Looks like I've got some damaged teeth. 4 on the ring and 1 on the pinion, bugger.