2 Noises from Transfer Case

[ArizonaRanger]

So I have a 1991 Ford Ranger 2.9L 5-speed manual 4x4.
The 4x4 system is a little weird, since it was originally a push-button electronic transfer case (I'm assuming BW 1354), but the previous owner added manual locking hubs. I haven't been able to shift into 4wd for a little over a year, and haven't bothered to check if it's the transfer case or the hubs or a fuse since I haven't needed 4wd.

Today I was driving from Tucson to Phoenix, and it did 100+ miles with no issues, when one mile from the house it suddenly started making 2 strange noises. It seemed to start when I shifted into 4th, there was a little bang. When I was coasting to a stop at a red light (~15mph), it suddenly started howling like a screaming banshee, but the noise stopped when the truck stopped. Then when I got moving again, I noticed a clunking coming from the transfer case. Approximately 1 clunk per turn of the wheels, so it's much more noticeable at low low speeds. And then when I was moving along in first (~10 mph), it started screaming again. I turned off the car, put it in neutral, and pushed it down the street, and clearly heard the clunking coming from the transfer case, but no screaming.

My main concern is safety, both for myself and the truck, since I really need to get it back to Tucson tomorrow. If I drive it, will I get in a wreck or do more damage to the truck? Is there anything I can do go make it work for a day? Also, what the heck is it?! I haven't had a chance to put it up on a lift, so I can't figure out where the screaming is coming from, but it was loud enough to bother the entire neighborhood.

Thank y'all so much for any advice.

 

[AllanD]

UNBOLT the front driveshaft, remove it and carry it in the bed.

This will eliminate several of the possibilities...

Check and make sure that ou have oil in the T-case and front diff.
and make sure the hubs are unlocked...

 

[ArizonaRanger]

Thank you for the suggestion.

This morning I got under there and started wiggling and banging on things. The front driveshaft is definitely not connected to the front wheels, I turned it manually both ways and it spun the axle but not the tires. I tried turning the main driveshaft, and it seemed to make maybe a quarter of a turn and then clunk, and then start turning the rear wheels.

When my tools arrive with my friends, I'll unbolt the front and check fluids.

 

[ArizonaRanger]

Well I took the front driveshaft off, and it didn't help. I checked the fluid in the transfer case, and it was pretty low, so I filled it up and headed down to Tucson. Since the noises were occurring once per revolution of the driveshaft, they kind of merged together into a hum at high speeds and got drowned out by road noise. When I exited the freeway in Tucson, the noise was gone. I don't know how, but at some point in the 100 mile trip whatever was loose managed to bang itself back into place. Nothing since then, but I'm going to keep my eyes open for a used transfer case, and my ears open for anything new with the truck.