Driveline Vibration After Gearbox Removal And Reinstall

[turboedsloth]

20mm is a lot of movement for a 1piece. If you grab the yoke on the diff does that move back and forth the 20mm? if so that is u/s and will need attention.

If it was to long the workshop would have had a tiny bit of trouble getting it out which you said earlier they reckon if was fine, if it was to long it would either bottom out on the speedo gear in the back of the box or bottom out in the bottom of the yoke on the output shaft. They are designed to move a tiny bit up and down the output shaft to deal with suspension movement when under driving conditions.

Is it possible for you to check the 1 piece length next to a stock tailshaft? Or to even get the balancing on it checked?

[jiffo]

20mm is a lot of movement for a 1piece. If you grab the yoke on the diff does that move back and forth the 20mm? if so that is u/s and will need attention.

If it was to long the workshop would have had a tiny bit of trouble getting it out which you said earlier they reckon if was fine, if it was to long it would either bottom out on the speedo gear in the back of the box or bottom out in the bottom of the yoke on the output shaft..............

The OP's sig says it's a GT4, so it won't have a sliding yoke at the box.

As a 2-piece, it would have had a conventional uni at the diff, a CV at the centre bearing and another CV at the box.

As a 1-piece, who knows what they did?

Either way, stuffed diff insulating rubbers won't help the prop shaft.

[GTRPowa]

Is it a harmonic vibration? Like when you have a poorly balanced wheel/tyre?

Or is it a metal to metal vibration, like random banging?

If it's a speed related harmonic vibration, and it does it when in neutral and rolling along, it's your tailshaft/diff/axles. Now all things being equal (if nobody thrashed it without your knowledge) the diff "shouldn't" just stuff out. Not to mention they don't usually cause much of a vibration without a lot of noise associated with it. The axles etc, well they shouldn't have even gone that far back.

My subframe bushes are stuffed, and if you search Google, you'll see forums all around the world with this common problem. While causing other suspension anomalies, you don't get speed related vibrations, and again, not instantly after taking it to a mechanic.

I'd put my money on the tailshaft. Get it balanced, any gearbox/tailshaft place with a balancer can do it, have it checked. This is assuming it's speed related vibration with the car in neutral.

To check shaft length quickly yourself, remove the bolts from the pinion gear on the diff and push the shaft towards the box. When it stops, you can mesaure the length between the shaft and diff's pinion gear. I'd have to get the book out to know the measurement (if it even has one), but you'd probably want to see about 20mm gap. (< My guess) If it's like, 5mm gap, or around that, I could safely say that's probably too long, but even then it shouldn't cause a speed related vibration unless the gap was like 0mm and you really had to force it in..

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If it's engine/rev related vibration when in netural. It's quite possibly the flywheel/clutch/plate/input shaft/etc. You'd have to have the box off to check this out.

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Cheapest thing you could do right now would be to fit a friends shaft if you can get one, or get yours balanced. And if you don't care about taking it somewhere else, get it independently checked.

Good day

[GTRPowa]

Just to add, isn't it the consensus that they use 2 piece shafts because they have less torque flex/warp? (which causes vibrations under load?)

[CeJay]

I can only describe it as a regular vibration (something related to rotation) which you could feel throughout the car Varies at different revs. It's nothing at all like a wheel alignment vibration. It was originally only going when in gear, but on a recent test drive after the clutch and flywheel were done it started doing it when it was in neutral and coasting as well. If nothing else thanks for some of the tips, I will talk to the shop it is going back to. I'll do some searching re subframe bushes etc as well, thanks for the heads-up.

If anyone in Sydney has a spare GTR tailshaft I could borrow that would be good. Unfortunately I cant check any of this stuff myself as the car is in sydney but I will get it followed up. Might ask for the tailshaft to be balanced, I find it hard to believe it is out of wack after 5 months though (new tailshaft) But at this stage I will check anything. The shop in canberra I had the car at initially was telling me the gap was 0mm, but the sydney shop said the tailshaft length was fine.

At this stage I am just getting really fed up with the whole run around, as I am getting two vastly different opinions from two shops that have worked on the car. One in canberra and one in Sydney.

Is it a harmonic vibration? Like when you have a poorly balanced wheel/tyre?

Or is it a metal to metal vibration, like random banging?

If it's a speed related harmonic vibration, and it does it when in neutral and rolling along, it's your tailshaft/diff/axles. Now all things being equal (if nobody thrashed it without your knowledge) the diff "shouldn't" just stuff out. Not to mention they don't usually cause much of a vibration without a lot of noise associated with it. The axles etc, well they shouldn't have even gone that far back.

My subframe bushes are stuffed, and if you search Google, you'll see forums all around the world with this common problem. While causing other suspension anomalies, you don't get speed related vibrations, and again, not instantly after taking it to a mechanic.

I'd put my money on the tailshaft. Get it balanced, any gearbox/tailshaft place with a balancer can do it, have it checked. This is assuming it's speed related vibration with the car in neutral.

To check shaft length quickly yourself, remove the bolts from the pinion gear on the diff and push the shaft towards the box. When it stops, you can mesaure the length between the shaft and diff's pinion gear. I'd have to get the book out to know the measurement (if it even has one), but you'd probably want to see about 20mm gap. (< My guess) If it's like, 5mm gap, or around that, I could safely say that's probably too long, but even then it shouldn't cause a speed related vibration unless the gap was like 0mm and you really had to force it in..

-----

If it's engine/rev related vibration when in netural. It's quite possibly the flywheel/clutch/plate/input shaft/etc. You'd have to have the box off to check this out.

---

Cheapest thing you could do right now would be to fit a friends shaft if you can get one, or get yours balanced. And if you don't care about taking it somewhere else, get it independently checked.

Good day

[GTRPowa]

I just read the manual. It mentions (as someone else did in this thread) that there are many alignment marks for the prop shafts.

Axial play is 0.6mm, so by rotating the shaft at the gearbox end with the gearbox in neutral, you should'nt see more than that. It mentions length, but for the stock 2 tube setup, which is 392+597mm. I don't know if that includes the centre bearing, yoke etc.

It mentions that on the gearbox AND diff, there are mating marks (or should have been drawn on there before it was removed.) So you'd have marks on the diff, gearbox, and both ends of the shaft. It also mentions rotating the diff 90 degrees, and try again, if not try 180, and 270 degrees. This is where the prop shaft mates with the diff.

At the end of the day, if it's balance was checked, is the correct length, and is mated to the gearbox and diff with the correct alignment, you could then eliminate the shaft.

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Try this exact sequence as well. - Park. Gearbox neutral, clutch out, rev the engine, also, try holding at 4000rpm, then at 3000, etc. Do you feel the SAME vibrations at ANY stage during ANY of this?

Just remember being in neutral is the key. You can test the input end of the box by being in neutral while parked, revving engine, etc. You can test the output end of the box while the car is moving at various speeds, again in neutral. I can suggest that it will only vibrate during one of these testsm unless it's the clutch/flywheel, in that case you'd feel it on both tests. Eliminate.

Edited January 7, 2011 by GTRPowa

[CeJay]

Have talked with the shop again.

There is the correct clearance at the back of the shaft, there is the correct clearance at the front of the shaft. Shaft has been balanced. Tailshaft is now being rechecked by the shop that built the shaft. Unfortunately the shop hasn't been able to find an original shaft that will fit my car. Due to it being a 4 door GTS4. They tried a few, which didn't fit 100% correctly.

I will double check with the shop re mating the shaft correctly to the diff, Which manual are you looking at? The GTR workshop manual?

When I had the car it did start to do it when I put it in neutral, however not when the car was stationary. I did test various rpm's and this didn't seem to do anything.

The shop is also getting my wheels checked, to ensure nothing is wrong with them.

At this stage if this does not fix the issue they shop I have the car at is looking at taking the gbox apart to look at it.

It could be the clutch or the flywheel, but I doubt it, as they were just replaced when first troubleshooting the car.

The only other data I have is the vibration seems to get worse the warmer the car is.

I just read the manual. It mentions (as someone else did in this thread) that there are many alignment marks for the prop shafts.

Axial play is 0.6mm, so by rotating the shaft at the gearbox end with the gearbox in neutral, you should'nt see more than that. It mentions length, but for the stock 2 tube setup, which is 392+597mm. I don't know if that includes the centre bearing, yoke etc.

It mentions that on the gearbox AND diff, there are mating marks (or should have been drawn on there before it was removed.) So you'd have marks on the diff, gearbox, and both ends of the shaft. It also mentions rotating the diff 90 degrees, and try again, if not try 180, and 270 degrees. This is where the prop shaft mates with the diff.

At the end of the day, if it's balance was checked, is the correct length, and is mated to the gearbox and diff with the correct alignment, you could then eliminate the shaft.

---

Try this exact sequence as well. - Park. Gearbox neutral, clutch out, rev the engine, also, try holding at 4000rpm, then at 3000, etc. Do you feel the SAME vibrations at ANY stage during ANY of this?

Just remember being in neutral is the key. You can test the input end of the box by being in neutral while parked, revving engine, etc. You can test the output end of the box while the car is moving at various speeds, again in neutral. I can suggest that it will only vibrate during one of these testsm unless it's the clutch/flywheel, in that case you'd feel it on both tests. Eliminate.

[CeJay]

Well, it is looking more and more like my 5-6 month old tailshaft is bent. Turns out the builder of the tailshaft hasn't balanced it or checked it, and supposedly they have a reputation for making bad tailshafts, or tailshafts that fail after a few months.

Will find out more in the next few days after a proper report is done. But a certain well known shop in sydney can get stuffed for all I care at the moment, for their complete lack of customer service.

I do give the thumbs up to Award diffs and gearbox for helping progress the issue though. Would recommend them to anyone.

[CeJay]

Well long story short it appears my tailshaft isn't bent but looks like it has been dropped on the floor, and the UV/CV joint was reassembled incorrectly thereby causing my vibration issues, its been inspected and reassembled properly. Will see how it goes once its been put back in. Not bloody happy...

I do give a thumbs up to Metroplitan Driveshafts in Granville and Award diffs for sorting out this whole mess. Would recommend them to anyone.

[CeJay]

Drove the car back from sydney, no vibration issues, funny that... will be following this matter up with the canberra shop I took the car to, when all this bullshit began.

[Scooby]

Good to see it sorted Chris

[CeJay]

Thanks

Well im in that wonderful situation where no one wants to take responsibility for the stuffed tailshaft. While I have my suspicions looks like it would be difficult to prove anything.... I would still recommend the shops in sydney to sort any issues.