Manual transmission noise, 2000 Xterra

[Jroper4]

I have had this 2000 Xterra for around 4 years and in the last 3 months or so there has been a noise that has been gradually getting louder. Last winter (a year ago) there was a noise that I assumed was a throw out bearing but it went away so I just figured that I would wait and see if it came back. Well now it has gotten loud enough that I feel I need to do something before I have a major breakdown but I don't want to tear into it without a few suggestions from other mechanics. I have worked as a mechanic for roughly 16 years but I haven't heard anything quite like this before. It is a grinding noise in 1st, 2nd, 3rd, and 5th, but fourth sounds ok. you cannot feel it in the shifter and it shifts into all gears just fine. It almost is like the counter shaft bearings but I am not sure of the power flow through the trans. The throw out bearing noise has come back but I cannot pin all of the noise to it or the clutch. It has 335,000 miles on it and I have no idea if or when the clutch was ever done. I would assume it has but one never knows. I have personally put over 200,000 on a Kia clutch.

If anyone knows the power flow through the trans or has had experience with this issue I would appreciate any input i can get. Also I have not been able to climb under it yet but I was wondering about crankshaft end play allowing the flywheel to possibly rub on the back of the engine.

[Desert Rat]

Bearings and synchros going out on you. 335k? That trans doesn't owe you a thing. 200k is about what those manuals are usually good for before a rebuild.

Nissan transmissions are picky about the oil they use. It has to be GL4. You could try a drain and refill with some Redline MT90 - that's a GL4 specifically for Japanese manuals. It quieted down a synchro grind in my old 300zx. 4th gear is direct drive 1:1 ratio, and it's always the quiet gear.

Throwout bearing noise usually occurs if you have the trans in neutral, and the engine running without the clutch depressed. Makes kind of a humming noise.

[Jroper4]

Ok Thanks I guess. haha. I kinda figured on a rebuild but not sure its even worth the time or money. Being a Michigan vehicle the body is starting to fall off piece by piece.

[Desert Rat]

try the synthetic oil change and see if that quiets anything down over a few hundred miles.

[Jroper4]

Ok I will try it and let you know in a couple weeks if it seems to help.

[Jroper4]

Trying to locate it and I see it is not very easy to find in my area. May have to order it directly from the company. Were you able to buy it locally and if not how long does it take to get from Red Line? Curious as to how you feel about an Amsoil GL4? this is something that is a little easier to find in my area. I am going to check with Orielly's tomorrow to see if they can get the Red Line, they are the only place that i can find that might possibly be able to get it. No one else can even order it and the Red Line site doesn't show any dealers within 50 miles that carry it.

[Q451990]

As long as it's only a GL-4 and not a GL-4/GL-5 it should be OK. Nissan sells their own fluid called Nissan MTF p/n 999MPMTF00P - that's what I put in my truck. I didn't have noise issues, but the shifting was a lot smoother. I waited too long to put it in... 80K+ miles and the drain and fill plugs had never been touched

List is $12.49/quart, but if your dealership is like mine, they may mark it up beyond that...

[Jroper4]

I found that Orielly's could order it in. They said 1 day but ended up being 2 and it was around 17.00 a quart. Now for the scary part, draining it and checking for chunks of metal.

[Desert Rat]

pro tip.

It's easier filling from the shifter hole than it is on the fill plug. Unbolt the shift boots, and then remove the shifter and pour it on in.

[Jroper4]

Ok so I drained the fluid and found some pieces of metal that I would normally say look like parts of a large bearing race. 4 of them are about 1 inch long, 1/4 inch wide, and just thick enough that it cant be bent by hand. then there is another piece that is similar except it is a little longer and it two pieces riveted together at one end. this leads me to believe that that have come from somewhere else. I am trying to find a exploded view of the trans so I can perhaps find where these came from. I will drive it for a while and see if it quiets down with the new fluid in it. perhaps drain and refill once again if it sounds better to get more metal shavings out. Is there a way I could upload a picture of these pieces?

[Jroper4]

lets try this. not sure if this is how it works

[Jroper4]

this has something to give you an idea of the size of them

[Q451990]

Yikes... fresh fluid won't fix that Well... maybe it will help, since that stuff won't be banging around in there. There should be an exploded view in the factory service manual, available at www.nissanservicemanual.com

[Desert Rat]

no but getting that junk out of the trans certainly doesn't hurt.

I can't see the pics, but am guessing it's chunks of the synchros? Bearings are what usually cause catastrophic failures so there might still be hope. I'd just refill it with good oil and drive it til it grenades. AT 330k I just don't see the truck being worth putting a ton of money into.

[Jroper4]

It just drives me nuts because cosmetically it looks like hell but mechanically it has been a very sound vehicle. Granted it has some lifter noise but is a very strong running engine, T-case and axles work great, love trail riding with it. Anyway I hate to just grenade the transmission and haul it to a scrap yard. it would be nice to find someone that could use it for parts.

[Jroper4]

Oh and I dont think it's sychros, these are pieces of steel not brass. The only thing I can see in the diagram is it might be part of the shift forks or linkage. Not sure why any of that would have come apart though, never been hard to shift and never jammed it into any gears.

[Jroper4]

Well It seems to have quieted down a fair amount. It definitely has some clutch issues, noisy when holding the clutch in, sounds like throw out bearing or the pilot bearing is gummed up due to oil leak. cross my fingers now and hope for the best. maybe change the fluid out again in a couple months if it is still going.

Thanks for the help