So after my mechanic inspected the clunking sound, its coming from play in the drive train. The UJ's are fine..ZERO play, but..

They put the truck up on the lift and turned it on. Kept shifting from "D" to "R" and you could physically see the drive shaft rotate about an 1/16th of a full rotation. There is play in the rear diff, the center transfer case, and the front diff.

Not too sure how to go about this because the truck also needs a new front passenger wheel bearing and ball joints.

The truck drives just fine, the only symptom is the clunk. She's smooth as butter, quick on the take off, and plenty of torque up hills. Over all I think it would cost more than the truck is worth to fix all these things(not too sure though)

Any recommendations? Would simple fluid changes fix the issues of play in the drive train? The rear diff fluid was done about a month ago or so with OE recommendations. Otherwise she just gets regular oil changes/premium unleaded/fuil additives.

Needs valve cover gaskets and oil pan gaskets as well, however, I check the oil on her once a week and the level NEVER seems to drop. So not sure how serious the leaks are. I used the snake oil leak stopper and that seems to have worked because when I first got the truck, the oil level would from perfect level to NOTHING on the dip stick after a week.

Best,
Ashtray

P.S. also this is for my P38, not the Disco.

 

Wow! Full to nothing on the dip stick in one week!!

How long have you had this truck? Did it clunk the whole time? That is not unusual in a D2 drive train either, actually rather normal. Pretty sure it has nothing to do with fluids. Just an old school system with a lot of moving parts. D2's will all do that if you are quick on and off the pedal, especially if you suddenly go from coasting to acceleration, or vice versa. If you use a soft foot on the pedal you can learn to make it not clunk... Try it, if so then I wouldn't worry. If not then you have other issues, which is highly possible. Those could be rear drive shaft. rotoflex, transfer case, worn diffs, etc.

Losing that much oil is another story. Voodoo oil additive is only covering the symptom, you will have to address that. There must be a ton of oil on the entire bottom of the car. clean it up and find the leaks.

PS, I also have a 98 P38

 

Well, I actually have already mastered it not clunking by footwork. But every now and again it'll do it no matter what. Especially when turning the wheel while reversing/departing.

As for the oil, Yes. I am aware I gotta get it taken care of. For now I'm just happy it's holding all of its oil. Priority are the valve cover gaskets and oil pan gasket.

 

Check the oil separator in the passenger side valve cover, In the D2 section you will see in the stickes a PCV308 mod. You can do that to your P38 too. If it is clogged that will lead to valve cover leaks... But losing all your oil in a short time has to be something bigger than that.

 

Do as Dave said for the pvc mod and just torque down the valve cover bolts. It helps huge. Plus if you run 20-50 rotella diesel oil- non synthetic helps a lot too.
As for the clunk, I also have it but I take it easy and don’t let it bother me.
if you get the oil pan gasket done might worth doing the main seals if not much more$