Play in the front drive line?

I have been hearing some "clunking" when going from R to P, and P to R. Even hear it from time to time when I come to a stop light, and then start back up again. I had asked the Stealership to check the U-joints on the driveshaft when it was in for inspection last week, and they said everything was fine.

Yesterday, I climbed under there and started checking for play in the drive lines (I don't want to believe that it is a tranny issue). Rear shaft was tight and no issues. Front shaft....had about 1/4" of play in it. I can hear the clunking in the front diff. I am assuming that there should be NO PLAY but since this is my first go round with a JEEP product, I wanted to ask.....is this normal? lol

What worries me, is when I went to change the diff fluids over to synthetic, I couldn't get the front diff cover off because the previous owner went crazy with a grey liquid gasket that is tight enough to keep out a radiation attack. I had to suck the fluid out of the fill plug.

I didn't see any metal in the fluid I removed, but who is to say that the metal pieces (if there are any in there) were too big to fit into my little suction hose. Now I really wish I had been able to get that cover off and look at things.

What say you all?

Take a utility knife and a putty knife to that diff cover... it'll pop off eventually. Using the putty knife and a mallet may split it off nicely. I usually like to hose my diffs out with brake cleaner before putting new fluid in, and I'm probably going to stick a neodymium magnet in the bottom of the housing on each of mine to pick up filings next time I have them open.

What year & which axle?

I have a '98 w/d30 and it was just rebuilt (new gearing and a locker) I have about the same amount of play but haven't noticed any weird noises.

BTW that grey liquid gasket is probably OEM. You just have to really work at it to get it off. Be careful not to bend the cover.

OK... a "clunk" when going into gear from park. Unless you're in 4-wheel drive, the front doesn't get any load (torque) from the transfer case, so it's probably the rear causing the clunk.

when you check for u-joint play, vehicle needs to be in neutral (wheels blocked, of course) to "unload" the rear driveline. Otherwise, any incline at all will tighten up the rear driveline and axle gears since vehicle is in park and rear is holding it from rolling.

Both front and rear driveshafts will turn a little, even with perfect gears.

Flyfisher said:

OK... a "clunk" when going into gear from park. Unless you're in 4-wheel drive, the front doesn't get any load (torque) from the transfer case, so it's probably the rear causing the clunk.

when you check for u-joint play, vehicle needs to be in neutral (wheels blocked, of course) to "unload" the rear driveline. Otherwise, any incline at all will tighten up the rear driveline and axle gears since vehicle is in park and rear is holding it from rolling.

Both front and rear driveshafts will turn a little, even with perfect gears.

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x2. Try greasing the driveshaft slip joint with some heavy grease.

Also, please try sharing year/engine/trans/transfer case info, plus mods if applicable, with each post.

PS--when was the last time you checked your trans and motor mounts?

joe_peters said:

x2. Try greasing the driveshaft slip joint with some heavy grease.

Also, please try sharing year/engine/trans/transfer case info, plus mods if applicable, with each post.

PS--when was the last time you checked your trans and motor mounts?

Click to expand...

Joe, you are like my personal mechanic. You have chimed in on every question I have had. I appreciate it.

I have never checked the tranny or engine mounts.

I was just out and about over lunch. When you go from D to R and particularly going from R to D is the loudest "clunk." I will have to climb under there later with the back wheels chaulked and in N to check for play in the rear line. Need to replace my grease gun anyways, so I will grease up every nipple I can find.

And this is a 1999 XJ with 4.0L engine and AW-4 tranny. Rear diff is 8.25" and front is D30.

Mudshack said:

... When you go from D to R and particularly going from R to D is the loudest "clunk."..

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This is a common noise as age and mileage open up the tolerances in your drive line. The proper name for it is drive line lash. The simplest solution is to wait 10-15 seconds in Neutral when shifting between D and R for the idle speed to drop a bit. Either way, this is not an issue that needs to be addressed in any way other than turning up the stereo.

It must be a Jeep thing. lol