Vibration when off the pedal.

[mudski]

I have this vibration when I'm off the pedal. But its only in 5th gear at any RPM. 5th at any RPM I don't feel it. 3rd, I think I feel it but its ever so slight I'm thinking that may just be the 3inch zorst doing that.
Engine mounts are fine, tranny mounts good. New uni's in the rear tail shaft done about three months ago.
So only in 5th it is. Say I'm doing 80k's in 4th, let off the pedal, its smooth, chuck it in 5th, let off the pedal and the vibration is there.
I'm thinking it has to be in the gearbox as it only does it in one gear at any RPM and speed. I can't see it being the tail shaft or rear diff as if it were it would/ should do it in any gear as the rotations of the tail shaft and rear diff don't change on what gear your in.
I changed the oil in the gearbox around 8 months ago too that the oil should still be good.
Healy!!! what did you do with your old gearbox that was ripped out of your troll mate. I may need it.

[Bloodyaussie]

That was an exchange... I have to replace my diff oil again as the vibration is back and a guy I was talking to the other day said you sometimes need to change the oil 4 times?????

[Col.T]

Muddy,
I reckon your logic re. revs in all parts of the drive train is good and pretty much leaves you with 5th. gear as the only place to go. As long as the vibes occur ONLY in 5th and at any speed/revs ONLY in 5th that looks like the problem.
Hate to say it but glad it's not mine. Still, you never know your luck in a mud hole do you.
Regards,
Col

[mudski]

Yeah. I'm hoping its not what I think it is. I really don't know how to tackle this as it is getting worse. Slowly, but it is worse.

[Bloodyaussie]

Change your diff oil first as it is the cheapest with only needing 2lt in there??

[Sir Roofy]

i have this vibration when i'm off the pedal. But its only in 5th gear at any rpm. 5th at any rpm i don't feel it. 3rd, i think i feel it but its ever so slight i'm thinking that may just be the 3inch zorst doing that.
Engine mounts are fine, tranny mounts good. New uni's in the rear tail shaft done about three months ago.
So only in 5th it is. Say i'm doing 80k's in 4th, let off the pedal, its smooth, chuck it in 5th, let off the pedal and the vibration is there.
I'm thinking it has to be in the gearbox as it only does it in one gear at any rpm and speed. I can't see it being the tail shaft or rear diff as if it were it would/ should do it in any gear as the rotations of the tail shaft and rear diff don't change on what gear your in.
I changed the oil in the gearbox around 8 months ago too that the oil should still be good.
Healy!!! What did you do with your old gearbox that was ripped out of your troll mate. I may need it.

mmmmmm id say its stress you,ve done so much work on it lately
poor truck does,nt know if its coming or going lmao

[mudski]

Change your diff oil first as it is the cheapest with only needing 2lt in there??

Did ladt week. And it was 4ltrs too. I might drop the gearbox oil and see what the oil is like. But I think I may have to look fir a gearbox now and the 4.2 will have to go further down the list. :thumbdown:

I tapped that app

[mudski]

Havent had a chance to have a good look. But can I remove the transfer case and the back cover of the gearbox to access fifth gear while the gearbox is still in the car?

[threedogs]

Isn't 5th gear the weakest link in the gear box??

[mudski]

Yeah there has been an upgrade to fix fifth gear from stripping the spline in the inside of the gear, new shaft with a longer spline and also a new gear to suit. TBH I don't even know if this is the start of the fifth gear going, as when you look at the gearbox it looks like someone has had it apart. I certainly doesn't look like its from a 12 year old car. The engine was newísh when I bought it, the it already had a solid flywheel in it when I did the clutch last year. So I dunno.
Just let it go until it goes boom? Or pull it apart now? I may be even looking in the wrong area for the said problem. I think I'll drop the oil again and see...

[threedogs]

Nothing in my manual relates to a vibration in 5th gear.
Sorry buddy I'll ask around on my travels for you.
you can change oil till the cows come home but
dropping oil will give you tell tale sign of filings.
Will be drivable till you get all your parts together' yo ho Gearbox build at Mudski's

[mudski]

I really don't need or can afford a gearbox rebuild right now. Especially doing it on the floor of my garage. Jonathan knows what it was like when we did the clutch....

[threedogs]

Who can, do you think it will last say 6 months, iyo

[mudski]

Hmm dunno mate. I think I will just risk it.

[threedogs]

Suppose you have to how different is the gq box?
Got idea????

[nissannewby]

Suppose you have to how different is the gq box?
Got idea????

The shifter is in a different location on the GQ box, Im not 100% but you may be able to just swap over the tops as the rest of the box is same.

Mudski, do you tow anything with your vehicle? How much load do you carry all the time? Is yours pre 03?
The earlier GU boxes do have a weaker 5th gear.

[mudski]

Hey Mat. She's an '01 model and I am aware of this issue. But Like I have mention mate, the gearbox looks very clean. No oil leaks, none on the engine at all, I know the box has been out before, for the clutch, pre my time. But I don't know if the gearobx has been touched. When I drained the oil in it last year it was very clean. As for towing. Next to zero, but soon there will be a camper trailer being towed behind it. Just for weekend trips etc etc.
If I were to get another box I would prefer to get a GU one...

[mudski]

This is starting to stress me out now. Every time I drive it I'm just waiting for the inevitable now. Spoke with a guy a Patrol A Part and he says the vibration is the tell tale sign. Haven't told the boss yet as last year when the clutch went she went off and wanted me to sell the car.
This isn't going to down well...

I tapped that app

[nissannewby]

It would seem that way, be lucky yours is showing signs many people have had nothing until it lets go. You shouldn't have to rebuild the entire box, just install the updated 5th gear and associated parts. You probably have one of the more common boxes anyway as they were used in both the 3.0 and 4.2 models. My mrs has a spare GU box if you could hold out until October we might be able to strike something up. Does patrolapart do exchange items?

If it doesn't let go in a big way you should still be able to use the other 4 gears.

[mudski]

Thanks Matt. PatrolAPart want $1750 for an exchange unit. Don't have that coin around me at the moment. I might have to just go with it and drive it until it goes boom but I will have to do something before christmas as we are going away then in the car so I will need it to be reliable.
As for rebuilding the box. I though of that but being my daily driver too I can't afford to be off the road too much, as, if I don't work I don't get paid. So I don't really know at this stage.

[lhurley]

This probably doesnt help much, but i know from experience to not let gearbox issues wait. Mines an auto so its slightly different, but i had poor performance and a noticeable sound, and trashed gearbox oil. Changed the oil, and just wanted it to last a few more months then i was going to get it rebuilt. Well as you can imagine the box didnt like that plan and went BOOM. So much so, that its no longer the original box and it cost me nearly $5k and nearly 2 months off the road. Had i just got it looked at straight away i could of waled away paying around 2k and a week or 2. Sorry if that adds more stress, im just letting you know what ive been through so you dont have to do the same.

[mudski]

From what I have read when it lets go it strips the internal spline off the 5th gear. So hopefully if it does that the broken parts won't jam in anything else. So at best I can drop the oil and keep going, for a bit.

Matt, does your spare box need a rebuild? I'm just thinking out aloud here too. If it doesn't and just needs the updated gear and shaft. Could you do it and then we get it shipped down? I'll pay you for the parts and your time of course.
Like I said I'm thinking out aloud here. Nothing set in concrete....Just trying to work out the best and easiest way so I'm not off the road too long and out of pocket too much. As my pockets are quite shallow right now.
Also I'm wondering if the tailshaft was out of balance would this cause it? But being only in 5th I doubt it. I'm just hoping its something else. As I did replace the uni's, and the end yoke on the diff end, on one cup of the yoke I had to linish it out only a small amount. As when I pressed the cup in I didn't see that it wasn't going in dead straight and the cup dug into the yoke. But I applied some quick metal after the linishing and I still had to press it in anyway, all circlips when in good and all was tight so I doubt its that.

[threedogs]

Could jump underneath and grab the tail shaft near all yokes and try and push up/down to feel for any play.
To me if it did that would translate to all gears not just 5th, and you're vibration is 5th gear specific

[mudski]

Yeah I know TD. I'm just kinda hoping thats all. Everything is tight as a fishes bum in the tailshaft department.

[nissannewby]

From what I have read when it lets go it strips the internal spline off the 5th gear. So hopefully if it does that the broken parts won't jam in anything else. So at best I can drop the oil and keep going, for a bit.

Matt, does your spare box need a rebuild? I'm just thinking out aloud here too. If it doesn't and just needs the updated gear and shaft. Could you do it and then we get it shipped down? I'll pay you for the parts and your time of course.
Like I said I'm thinking out aloud here. Nothing set in concrete....Just trying to work out the best and easiest way so I'm not off the road too long and out of pocket too much. As my pockets are quite shallow right now.
Also I'm wondering if the tailshaft was out of balance would this cause it? But being only in 5th I doubt it. I'm just hoping its something else. As I did replace the uni's, and the end yoke on the diff end, on one cup of the yoke I had to linish it out only a small amount. As when I pressed the cup in I didn't see that it wasn't going in dead straight and the cup dug into the yoke. But I applied some quick metal after the linishing and I still had to press it in anyway, all circlips when in good and all was tight so I doubt its that.

Im not entirely sure of the gearbox but if it was a path you decided to take then I could do the work you describe.
With your tailshaft could you grab one from someone you know down there just to rule that out? Just swap it out and go for a quick run.
Might be a longshot but your front hubs aren't locked are they?

[threedogs]

Tight as a mouses ear hole is the correct term, Yeah may have thrown
a weight off the tail shaft , bottomed out hard on any recent forays into the bush

[mudski]

With your tailshaft could you grab one from someone you know down there just to rule that out? Just swap it out and go for a quick run.
Might be a longshot but your front hubs aren't locked are they?
Getting a hold of another tailshaft is what i want to do first. Just to rule it out. Finding one is the next thing. I might have to put out an APB!!!
As for the front hubs. I had to actually go outside to make sure as I didn't trust myself...There not locked.

[nissannewby]

Getting a hold of another tailshaft is what i want to do first. Just to rule it out. Finding one is the next thing. I might have to put out an APB!!!
As for the front hubs. I had to actually go outside to make sure as I didn't trust myself...There not locked.

It was only a longshot. Is healy far from you? Might work out since he has taken his off the road now.

[Bloodyaussie]

Yeah and maybe a gearbox!!!

[mudnut]

Maybe a radical idea, but could you take the tail shaft and unis off and drive it with the front wheels providing drive only, just to see if the vibration is still there? Or do you have an auto locker?

[mudski]

Yeah and maybe a gearbox!!!
Hmmmm.....
31854

[mudski]

Maybe a radical idea, but could you take the tail shaft and unis off and drive it with the front wheels providing drive only, just to see if the vibration is still there? Or do you have an auto locker?
Its it 5th mate so I would need to be doing atleast 80k's. I don't know how safe that would be running off the front shaft only...But I see your logic.

[mudnut]

I wouldn't know what would be a safe speed to do. Maybe some adventurous type has done it and could give feedback?

[mudski]

Update...The vibration is slowly coming up in 3rd gear when off the pedal too. Its very slight but its there.

[happygu]

Mudski,

The bad thing is that it sounds like the gearbox is on its way out with the 5th gear problem.

The good news, it there is any, is that others have driven right across the country minus 5th gear, and made it fine.

It seems, that if it goes, it is still driveable, and driveable for quite a while too.

Mic

[mudski]

Yeah I hope....

[mudski]

I have now decided to just drive it until it dies. To do it now its not going to be much cheaper than doing it later on when it finally goes as I probably would do it the same way, remove and refit a reco'ed box. So here's hoping it lasts until after the snow trip.

[threedogs]

That dropping the tail shaft and driving home is fine if your stuck or fault finding
wouldn't recommend it all the time though.

The longer it takes to fail at least give you more time to suss stuff out, for
a more permanent fix

[mudski]

I took the tailshaft out last week and checked the uni's and rotated the shaft to where is bolts up. Everything is fine. It won't be the shaft as it goes as soon as you put your foot on the clutch...

[threedogs]

Not that spigot bearing on the clutch?
Cant loosen off the bell housing, then stall it in 5th gear can you.?
Don't laugh it may re align everything, then tighten all up
pilot bush out of whack

[mudski]

Shouldn't be, the spigot bearing in the flywheel and thrust bearing on the carrier were both new when I did the clutch last November.

[threedogs]

How many bog holes in between those 9 months ?

[mudski]

Won't be too many. I don't get a lot of time to get out lately...

[threedogs]

Does it feel like its getting worse ?
Maybe check oil for metal filings.

[mudski]

I'm going to drop the oil next week sometime and have a look at that. Working seven days a week atm just to catch up, then I do my shite on Ebay at night after I get home... man I'm tired...