[Sheffieldashley6]

So in April of this year I took my car to the dealership to have the fuel sending unit replaced. At that time they told me my timing chain needed replaced as well. So I replaced that then they told me that my rear differential was bad and needed replaced. I had just spent a large chunk of money on the timing so I decided to get a second opinion since i was quoted over 3K for the rear differential replacement. They told me that there where metal shavings and burnt oil when they popped the seal. I had them replace the fluid as they said it would help for a while. When I took it to a local shop recomended by a friend he said it was just the pinion bearing and he charged me $1200. When I got my car back it was making a noise even louder than before. When I asked about the noise I was told that final adjustments needed to be made after I drove it for a while. I have taken it back several times within the past few months and every time he tightens the "crushable washer" and the noise is better for a while. When I go on a long drive or after several weeks of normal daily driving the noise comes back. I'm starting to get tired of going back for adjustments. His explanation was that the crushable washer takes alot to be tightened and he gets it as tight as he can the only way to fix it is to keep adjusting it. Can anyone tell me if this makes sense? The noise is a whining noise that started just when coasting and now it seems to be anytime I am driving and sometimes it seems like maybe there is a catching or clicking when I go from coasting to accelerration but it's not consistent and it doesn't seem to be at all speeds so it's difficult to point out. I'm pretty clueless when it comes to this stuff.

 

[intender]

the whine when you let off the throttle is the backlash not being set properly. to set the backlash you have to pull the whole differential out unless there is something I dont know about the second gens being different from other cars.....

Unless the guy is pulling the whole thing apart everytime I am not sure what exactly he is doing.

 

[Sheffieldashley6]

I'm pretty sure he is because he mentioned something about having to pull it all apart the first time I took it to get "adjusted". I leave my car with him for half a day at least each time. This is why it has been so frustrating, It is time consuming to have your car in a shop for half a day every other month. I really just would like it fixed but since I know absolutly nothing about cars and what research I can find I don't understand completely so I feel like an idiot when I try to tell him he needs to do something different or that he didn't fix it right. I don't know if he fixed it right or not. The dealership and AAMCO both said I need the whole rear end replaced. The other private shop said it was only the pinion bearings as well so it was split down the middle with what to do. I went with the cheaper option (haha). From what I can figure, the crushable washer or sleve for the bearings is what he used because he wasn't sure of the pre load specifications. The crushable washer takes quite a bit of force to tighten. I think it's possible that he just didn't have the equipment to tighten it enough the first time so it was as tight as he could get it. The more I drive it the looser it becomes and the more he can tighten it each time. When he tightens it really well, the sound is completely gone. I have changed the fluid and drove it quite a bit and had it checked by an outside source other than his shop and there are no flakes and the fluid looks good not burnt so that leads me to beleive that the problem is fixed since the origional fluid had metal in it and was burnt. Does any of this sound right?

 

[Fzzt]

Sounds to me like he doesn't know how to set up a rear end. At most you should have only needed to come back after a days driving just so he could check that the backlash hadn't opened up.
It takes great care and time to properly set everything up and just a small mistake (over tightening) can mean pulling it all out to replace shims or a crush washer.
BTW any mechanic worth his salt should be able to torque a pinion nut either that or shouldn't be playing around inside the rear end.

My advise is make him re-do it while you wait & watch or take it somewhere else and try to recoup some of the money he's soaked you for on the follow up visits.

These are not instructions for your vehicle but read the Assembly instructions so you understand what is being done & why. http://www.differentials.com/technical-help/installation-instructions

 

[Sheffieldashley6]

So assuming that I can get him to replace the parts but not right away, am I driving a ticking time bomb? I do a decent amount of daily driving, I don't want to break down. I say not right away because I had a similar problem when he did my breaks. The springs where damaged or whatever he did to him. I took it back 3 times and told him what I though the problem was and he finally replaced the parts after the 3rd time. I will be driving about 500 miles to visit family at christmas and I would rather not break down on the way there or on the way back. With finals week coming up it may be difficult to schedule a time for him to work on my car.

 

[intender]

backlash is one of those things that wont cause damage very fast, just premature wear more than likely. Unless you are constantly dumping the clutch or letting of the gas and then getting on it hard you should be fine. also it isnt one of those things that should require any new parts other than maybe that crush washer. I have never tore the x rear end apart so I dont know what all is in there. The backlash is more or less just the amount of play that is in your gears. you dont want to much play or the teeth dont engage properly, too tight and you wear everything down. either way it make noise.

when you say the noise gets better, is it just less after he works on it, or is it gone and then comes back. And is this guy charging you for each visit or including this work under the original price paid. I would not be paying the guy for anything additional. he should have had this right the first time.

 

[Sheffieldashley6]

The noise gets better but never completely goes away. He hasn't charged me for the visits for adjustments. I just paid for it at the initial repair. It is costing him $ in labor each time he has to adjust it so you would think that he would just want to do it right. I'm just going to ask him to replace the crush washer / nut and set the backlash correctly this time. Hopefully he will work with me on it.

 

[dezurtrat]

He should have only had to adjust it once and then possibly a recheck. Something is not right and I would get it to someone who knows what they are doing ASAP.

I know from experience the only thing you can do on these diffs is replace the pinion bearing/seal and axle bearings/seals. That's it. They can NOT be rebuilt otherwise. Nissan does not list the internal parts as buyable. A new or manufactured one is all they sell. I just had my second one replaced, thankfully under warranty.

 

[Bart]

I had my rear differential looked at last year. Initially, the mechanic thought it was a rear wheel bearing. Once it was on the hoist, he realized it was not the wheel bearings and I had him remove the cover on the rear diff. The bearings in the diff were cracked and needed replacement. But I also had the metal shavings in the fluid. Apparently, Nissan will not admit it, but the hardening treatment on the gear teeth is sub-standard and breaks down resulting in early wear of the gear teeth.
The cracked bearing in the diff were replaced and everything was tightened up and has been ok for the past year. But the gears in the diff will need replacing eventually. There are more robust aftermarket parts available for this problem, which I'm looking into now.

 

[dezurtrat]

^^^Yes, and that's was eventually causes these diffs to go. It's been known for a while, especially on the rear locker model, Dana didn't heat treat the gears properly.

I had my rear axle replaced due to the pinion gear being shot which is another whole story due to the dealer f'ing up the pinion bearing. But, Nissan wanted $3,000 for a re-manufactured rear axle or $3,300 for a new one. Yea Nissa. Way to go!