How urgent are CV-joints in a part time 4wd vehicle?

I have a 1989 Toyota pickup with part time 4wd and manual hubs. I noticed the other day, that the left outer CV joint had a nasty tear in it. It also does seem to clunk a little when turning left in 4wd. So given that the axle just sits there during 98% of my driving, do you think changing this should be a priority? Is this any less of an issue than with a FWD car?

For that matter, I’ve always wondered, what exactly does happen to a neglected CV joint on a front-drive car? I’ve always replaced them when the clicking gets very loud, but have always wondered if it will eventually stop transmitting power. Or could the wheel fall off?

If you consider driving your car urgent then it is urgent that you replace them, because if they fail 4WD or not, you are not going to be driving your car any further until it is replaced.

You do know that if you inspect the joints regularly, you can replace the boot and avoid a joint/axel replacement???

What the heck? This message from 5 months ago just came up to the top!

Although, incidentally, I’m not quite sure I agreed with Joe’s answer here. It still seems to me that the CV joint just sits there most of the time and that, consequently, worst case scenario would be that the 4wd would stop working.

You are right. Because he has manual locking front hubs he can run as long as he wants to in 2wd as the front axles will not turn.

Even if he didn’t have manual locking front hubs, it STILL wouldn’t be that big a deal, because there’s no power delivered through the front drive shaft when the rig is locked in 2wd.

Yes the CV joint can eventually fail if neglected long enough. If that occurs on a FWD car, you won’t have power at that wheel and if you don’t have a limited slip differential, the car is dead in the water. On your rig, even if you were in 4wd and one joint failed, you would still be able to move, because the transfer case is not “intelligent”, which is to say, it can’t selectively change its power bias (i.e. it’s locked in a 50/50 split, front and rear).