A few weeks ago I started to notice that my 1987 Toyota Pick-Up Truck (22R engine, short bed, 2WD, 5 Speed, 205K miles...named "The General T" after the famed Charger featured on the 1970's TV show "Dukes of Hazard") wasn't always rolling freely on inclines (such as when I was at a stop light), and sometimes there was even some noticeable resistance when backing-up out of a parking space -- but this condition always quickly went away, and I was off to motor happily. Thinking it might be a sticky brake caliper, I got a brake check at a local shop. The brakes checked-out okay, but the technician (who knows these trucks and has even owned 2 of similar vintage) said it was a problem with the rear-end differential. [I had sort of suspected this before I took it in, but didn't want to bias his diagnosis.] With the truck on the lift, he demonstrated how if he rolled the driver's side wheel forward several turns and THEN rolled the wheel backwards that it froze-up. [Not a hard clanging, noisy, metal-on-metal stop, but sort of a "binding" stop.] If the wheel was then rotated forward just an inch or so, it would then rotate freely again, both forward AND backward past the point where just seconds ago it was "stuck." Huh? The above condition did not present itself on the passenger's side. The differential is a "limited slip" type -- or so I was told by a friend who gave it to me 5 years ago after we pulled it off a junker truck that he had had that itself had like 250K miles on. The technician suggested that the internal clutch plates (which negotiate the torque distribution between the wheels, as is my understanding) might have worn -- given all the miles and wear. The "U Joint" checked out OK as well. So, my question: Is there anything really, really UNSAFE about this worn differential...assuming its the internal clutch plates that are worn. Could it be anything else? Can I just put this problem in the category of "Another annoying thing about a 20 year old vehicle"? It's winter now, but in the spring (when it gets warmer) I'll be in a bit better situation to go to a junk yard and swap in another differential...in fact this was on my "to do" list anyway, as I want to experiment with another gear ratio to improve fuel economy. Could the cold weather have made this problem evident? I don't recall anything like this in the fall. Any other quick diagnostic tests I might be able to perform? I don't really drive very far from home, and I always carry a cell phone and my AAA card, so I have no real concerns about being inconvenienced: I just don't want to be driving down the road and having the whole differential pack-up as if someone had slammed on (and locked-up!) the rear brakes. Thoughts?