Bumps out of 4WD, Then Re-engages

[prossett]

Today in 4WD low range on the sands, my 1983 Jimmy with N208 transfer case suddenly bumped out of 4WD with a loud clang, the front wheels stopped spinning, and a second later bumped back in, re-engaging 4WD. This happened at pretty high revs, while climbing, and the 4WD lever in the cab didn't move (I think).

Where should I start troubleshooting? Any advice appreciated. I've already searched but found choppy info, though I couldn't really narrow down the search words.

I would immediately suspect the transfer case, and try looking at reasons it could slip out of gear and then back in. I've never opened one up before so I'd rather hear you guys out first.

 

[resurrected_jimmy]

A few common things to look for would be: contact between the shifter and the floor pan, worn out/broken transmission mount, linkage not adjusted properly, or the chain has stretched and is jumping over the gears

If you have a body lift I would look at linkage and contact before I condemed the t-case

 

[89GMCSuburban]

Are your hubs automatic or manual on the axle? If auto, they could be crapping out.

 

[prossett]

Ahhhh - hubs.... auto... had them out and re-packed two days ago...

But, would that be both hubs disengaging at the same time?

 

[PsychoticDeadGuy]

if your open front diff and just 1 hub unlocks then all the power will go over there and neither tire will spin...i think its your hubs. i got a pair of Warn manual hubs for sale...

 

[trikstark5]

I had a similiar problem with K5. Actually replaced the automatic hubs with Warn hubs and replaced the transmission mount. If you do replace the transmission mount, double check that your linkage is adjusted right for the transfer case.