It sounds to me like at least one of your u-joints needs replaced. My 97 did the same thing when the u-joint was going out. I thought from the sound I was hearing when I drove that the problem was in my front driveshaft but it turned out to be the u-joint at the rear differential that was bad. The fact that it's causing a vibration means it's about to fail completely and needs to be replaced. Just greasing it isn't going to do the job. There are either 3 or 4 u-joints in your driveline and I would spend the money and time to replace them all since you don't know the maintenance history. About mid-model year 97 Rover changed from a roto-flex coupler to a u-joint at the rear differential which is why I say 3 or 4 u-joints. U-joints are cheap and easy to replace. I bought all 4 u-joints for under $50 and it took me and a buddy about 2 hours to replace them all.

 

This is great information. I can't wait until I have some daylight to get under there and look for all of these parts/potential problems.

The thread with pics looks super helpful, too....thanks for recommending it DiscoMedic

No problem. Since I am still fairly new to rovers myself I am always glad when I actually can help. lol. Good luck changing them. Before I did mine I looked through every thread I could find on here that referred to UJ's. I came to the conclusion that I didn't want the cheapest I could find but that I wouldn't be doing enough hardcore off-roading to worry about the "perfect" UJ set-up. I went with UJ's from NAPA that were stamped as made in the USA instead of the chinese made UJ's that are so prolific now. If you have never replaced UJ's before don't get overwhelmed. It will take you a little longer to do it. Mine took about 2 1/2 or 3 hours but I had to really fight with mine and I didn't have a press. If you get into it and need help just ask on here. It is a little bit of a PITA to do this job but the satisfaction in doing it yourself will get you fired up to do something else. Good luck and have fun.

 

I am looking forward to it. I am going in on Monday to get parts and hopefully get to work. So, I don't HAVE to have a press?

Also, a few people have mentioned "vibration" but it is NOT a vibration at all. It is a thudding, knocking noise. When I let off the gas completely, it is as if the transfer case stop spinning the shaft, but the shaft has enough play in it that the momentum keeps it spinning for that extra 1/4 turn and then the play "runs out" and it clunks against the transfer case or gearing......again, I don't know what everything is called, but that is the best I can tell what is happening. Still sounding like UJ's? When this occurs, it causes the entire truck to buck and little bit.

 

the "clunking" sound is quite normal. Play in the driveshaft/propshaft is not normal. You should really get it looked at by someone that knows what they are doing. You can do serious damage to your truck's transmission if a u-joint fails and flops around, not a good thing. You should be able to get all of the parts for about $50, you should be able to find a driveline shop to redo the u-joints and centering ball for about $150 depending on where you live. Good luck. Phil

 

Yes, lock the CDL, remove the propshaft and drive it.

 

Hey guys, today I am getting my hands dirty under my Rover and redoing my front propshaft, but I have a quick question. If ALL 4 of my UJ's are greasable on a 97 Disco, can I assume that shafts have been rebuilt at some point? Everything I am seeing on here states that factory doesn't put greasable UJ's all the way around (both ends of front and rear shaft)

 

D1's came with greaseable u-joints.
If the clunk happens just once, when letting off the accelerator, then it's probably just normal drive train slop. There are a lot of gears that will become slightly worn and have a slight amount of play. When all that slack gets taken up it can amount to what seems like a loud clunk. It's hard to say if that's what you have, or something more, without actually driving it.

There are other places to get the clunk from the driveline. Worn bushings can contribute to it, loose fittings like in the radius arms, etc. Also the ball joint in the rear A-arm mount can cause a significant clunk.

I'd start by downloading the RAVE manual and reading the suspension and drive train sections, especially the illustrations that show the layout and identify the parts. It makes asking questions a lot better since you can use the correct terms so people will understand clearly what you're asking, not to mention you understanding their replies.