From the day I drove the truck off the lot, I have had a clunking issue appearing to come from what I thought was the rear diff. If you're cruising along around 45 mph in overdrive and you let off the throttle and coast down to 35 mph or so, stepping back on the throttle gives you a nice clunk.

I went back to the dealer (second time) for a test drive to hear the clunk. First time it was pouring rain and you could barely hear it. This time though, he got the full effect. Went with one of their senior techs who was a great guy. He said he could hear it actually double and triple clunk.

So I said do you need to pull the cover off and check it out? He said they could but normally they don't even mess with them. Too much work for too little result. Anyway, he said what I'm hearing is the play between the ring and pinion. Some of that is normal but on my truck he said the noise was excessive. Way too much clunk. He said he would get with the service manager and discuss it and take him for a test drive and let him hear the noise. He said what PROBABLY will happen is they will replace the whole rear axle.

So for all you people that have this on your next Gen X, if you think the noise is excessive, take it in. Posting about clunks on a message board, it's hard to get across just how loud a noise is in comparison to someone else claiming to have the same issue.

Maybe they'll come back and say Nissan said no way on a new diff. I got my fingers crossed as I don't want to get my hopes up to just to have Nissan squash 'em. Very nice guy though and totally agreed with me that he felt the noise was unacceptable. I'm guardedly happy right now.!

Well, I left the dealer at 10:30 AM and they just called (1:30) and said the new diff was on order. I can come get the X. They would call me when it comes in (3-5 days) and replace it and put me in a free rental to boot! Damn they were nice!

That's good to hear they are going to fix that diff. Bummer to have that trouble in such a new vehicle but it happens. Hope that cures the clunk!

good to hear that the stealership did what was right!!!!!!! you dont hear that that often.... LOL

Yea, these guys were awesome. Thoroughbred Nissan in Tucson.

OK, new diff is in. So far so good. No clunking or weird noises yet.
I crawled under there when I got home to check to make sure they changed the diff breather. There is NOT one on this diff. Yea, you read that right. I know where it was because I crawled under there to check it out on the factory diff after I read the Diff Breather Mod thread on thenewx.org. I'm getting the feeling this is a new version diff.
STAMPINGS ON REAR COVER
http://i8.photobucket.com/albums/a50/dezurtrat/Xterra/MainDanaLogo.jpg
85637
269-7
REV-C
051304
STICKER ON DIFF
DSN: 1810801028687
Part # 2008297
Dana P/N 8297
Ratio 3.36
01-11-2008 8:17
BRCD: X4RD

Did you post this over on TheNewX yet?

I bet they would like to see what they swapped it out with.

Yea, I did, I wanted someone to see if they can verify what part numbers are on their diff and see if they match.

OK, once I got it in the garage I crawled back under there with a light. There is a small flat square metal piece flush to the diff where the breather used to be. No threads showing. It looks like it's part of the axle. My gut feeling is they were supposed to change it and they didn't. Luckily I'm only a couple of miles from the dealer. I'm gunna run by in the morning.

OK, new breather is in. Thank God I looked under there to double check. They were totally cool and felt bad they forgot it. All is well again!

Yea, these guys were awesome. Thoroughbred Nissan in Tucson.

Hate to bring up an old thread, but these are the same guys that charged me 100 bucks, didn't even look at my car, and told me the engine was seized. So I I purchased another motor and went to swap it in and sure enough the battery cable is loose. I tightened it down and it fired right up. Thoroughbred has officially lost all my respect. they wanted 5400 to replace and engine and all it needed was a little torquing...

S*&T there is another noise i have been hearing on my x... well guess thats just another one to ask about.

There is a service bulletin on this now where they re flash the chip in the trans ecu. I'll find it for you.

Here you go:

http://i8.photobucket.com/albums/a50/dezurtrat/Xterra/NTB08-045.jpg

Well, so much for this TSB which never solved the issue. BUT, the infamous clunk is now completely gone. I recently had the leaking axle seals (with bearings) and leaking pinion seal replaced. I'm assuming now that it was related to the pinion gear.

My theory is the pinion nut wasn't torqued correctly from the factory but was done correctly when the seal was replaced. I guess it could have been the axle bearings but those would affect more of a side to side motion I would think but again I could be wrong.