Hi I have a 1999 Disco 1 with 135,000 miles on it. The tranny makes a clunk sound when shifting into reverse from drive. This is only when the truck is warmed up too. No sounds in the morning or after its been sitting for a few hours. Is this a u-joint problem or will I need to change the front drive shaft? Rather have it done sooner than losing my tranny. Thanks for any advice.

 

How often do you lube both drive shafts, when did you last check your ATF level, is it burned, when was it last changed?

 

ATF was just changed last summer. I'm going to have the shafts looked at.

 

Check your transfer case fluid. Mine was the same way untill I changed the fluid and it made it a lot quieter afterword. Your D1 doesnt have the double cardan joint that the DII's have. Might want to replaice the diff oil also

 

Sounds like a u-joint going out. Mine started that way when the u-joint at the rear diff started to die and continued to get more common as it got worse. It went from only making the clunk when I shifted into gear to clunking every time I accelerated. U-joints are pretty cheap and easy to replace and if you haven't been keeping them greased they probably need replaced.

 

The u-joints were good, the transfer case was about a quart low so refilling it has quieted the clunking down. Looks like I'm going to need to replace the transfer case in the near future.

 

A quart low will kill you t/case, you need to start taking batter care of your truck. I would highly suggest if the rest of your truck has been this neglected that you go thru and change all your fluids.
As for the u-joints, they have to be greased at least 2 times a year or they will fail, so have them inspected and greased or replaced ASAP.