Driveline Vibration After Gearbox Removal And Reinstall

[CeJay]

Have a bit of an issue at the moment and thought I would post a new thread for this as the problem is a bit unique.

Had the gbox rebuilt 4 or 5 months ago and had the tailshaft replaced with a one piece.

Now just recently I had a coolant leak through one of the pipes at the back of the engine. Took the car to a mechanics and long story short they advised me that they needed to drop the box to get at the hose. Fair enough I thought. While they were doing it I told them to replace the other hoses there, so the box would not have to be dropped again.

Upon removal they told me that the thrust bearing would need to be replaced as it was worn. I had them replace it. They said they had trouble getting the tailshaft out and putting it back in. Upon picking up the car they told me that there was a vibration and that the one piece tailshaft was too long, and there wasn't enough play in the tailshaft. Drove the car away and drove back after 500 metres as the driveline vibration was that bad. They still thought it was the tailshaft. This vibration was not there before dropping the car off at the mechanics.

The driveline vibration is a hard rotational noise, and quite bad, it doesn't increase though between 40 and 100. It is just as bad at both speeds, and seems to change more in relation to the revs the car is doing. The car is pretty much undrivable for any long drives as the vibration is too bad.

Took the car to one shop this morning and they told me they thought the tailshaft was fine and that it was probably more to do with something rubbing on the underneath of the car, or the clutch fork being bent or something not being reinstalled correctly. After talking with the place that rebuilt the gbox they seem to be pointing me to the same area, they indicated the tailshaft was fine, they had no problems installing it (was put on the car at the same time the gbox was rebuilt) The old tailshaft was given to the fabricators to measure and build a custome one piece off, and they thought it was something the mechanic has done.

Wanted to know if anyone else has had a similar issue? Or does anyone have any idea as to what the vibration might be. I am taking it to a gbox place tomorrow morning to have them have a test drive. I just am not comfortable at the moment taking it back to the mechanic that did the work if it is something they may have done wrong. I may take it back eventually, or may just get the gbox place to drop the box and investigate and see what the issue might be.

Any info or advice would be appreciated.

Thanks

[turboedsloth]

"They said they had trouble getting the tailshaft out and putting it back in"

I would be asking why this is so if the person that made it installed says it went in perfectly. If i were you i would take the car back to the mechanic and get them to pull the box back out whilst you were there and see what they have done to cause your car to be like this, Or take it to the gearbox place and have them pull it out and inspect the work that was done as they will hopefully know more than the other mechanic with it being the box.

[CeJay]

Currently working through this, but have had shops tell me it's anything from a loose flywheel, bent clutchfork, unbalanced tailshaft etcetra. Working with the shop that did the work at the moment. Either taking it back to them or a specialist Gearbox place. Currently pissed off with the entire situation, whoevers fault it is.

[Bayside Blue R34 GTV]

i say take it back to the mechanics that did the cooler piping and ask them to fix the problem. As you mentioned that it gets worse due to engine rev rather than speed so the tailshaft is out of the question. it could be anything before the box, best way to find out is to open it. Was the piping done at a reputable workshop? or just a small shop with apprentice working on the car without knowing what they are doing.

[Joe_89]

I had the same thing with a car after a new clutch was put in, had to take it back to them about 3 times to have the gearbox taken BACK out.

Ended up being the clutch itself being faulty (thats what they told me), but obviously something was out of balance, which is why it is worst at a very certain rpm.

But i would certainly NOT be taking to somewhere else first because when the cause is found, the garage that installed the clutch could then say it was the other garage that did it etc etc

So at very least, take it back, take them for a drive to show them the problem and see what they say before you do anything else

Anyway hopefully it all gets sorted without too much hassle, good luck mate

[CeJay]

Time will tell, The shop I had the work done is adamant that the problem is the tailshaft and not the gbox or something related to that, and while that may be the case, I am hesitant to take it back, when every over place thats taken the car for a test drive doesn't think it's a tailshaft issue, and think it's something clutch or gbox related. So I am a bit reticent taking it back.

[FineLine]

make sure the tail shaft is back in excactly the same bolt location it came out. Phase matching i think they call it.

If it isnt done it can create the problem you described.

It may not be as critical on a one piece shaft but is certainly worth a look.

[MrStabby]

make sure the tail shaft is back in excactly the same bolt location it came out. Phase matching i think they call it.

If it isnt done it can create the problem you described.

It may not be as critical on a one piece shaft but is certainly worth a look.

Good point. Look at the two uni joints - they want to be "out of phase" with each other, or 90 degrees if you look at the orientation of the pins in them.... not sure how to describe that better - am i making sense?.... If the unis are not removable from the tailshaft then you cant have this issue as it wont have been possible to reassemble it incorrectly on a one piece.

[CeJay]

I'll let the shop know when I drop it off, taking it elsewhere now as I just want it sorted and the other shop is busy.... Having a gearbox place remove the box next week to check, and also getting a tailshaft specialist to look at the tailshaft before it's taken out, and perhaps test it while it's out.

I don't really care if I don't get any compensation from the other shop now if it was their stuff up, I just want it sorted.

[R.3.2.G.T.R]

sad to hear you being dicked around, now the other shop doesn't have time for you, I'd still ask them to sort it as it was fine before they fiddled with it

[CeJay]

Second independent shop I took it to is now saying they think the tailshaft is too long. They tried a different gearbox mount and it made the vibration worse. They didn't take the gearbox out though. I find it all a bit baffling as it worked fine before. The only thing I can think of is that the tolerance of the tailshaft is so small that any slight misalignment or change in how the gearbox is mounted may be causing the issue. Or they installed the wrong throwout bearing.

I am now thinking of taking it back to sydney to have the gearbox place that put the tailshaft in and rebuilt the gearbox have a look at it. And the place that built the tailshaft is just down the road from them.

[CeJay]

Car is up in sydney. Gearbox out, have now been told the clutch is completely shagged, worse he has ever seen supposedly. So far havent been able to find anything wrong with the tailshaft. Flywheel also has scoring marks on it? Will talk to them tomorrow again. I am wondering though, can an incorrectly installed or wrong spigot bearing (or throwout bearing) cause clutch damage/wear?

Had the gbox out 5000kms ago,and 3 weeks ago, and drove around 200kms with the vibration due to it being a daily and taking it to several shops for a look. And neither shop told me the clutch was fuba then so it has me mystified how the clutch could get that f**ked in so short a time.

Will ask the shop more about their opinion on the tailshaft tomorrow.

[turboedsloth]

Is the spigot bearing or the input bearing shagged? Or even the input shaft? When the other workshop pulled the box out last time if they were any good (which from your first post im guessing they arent) they would have seen if there was a large amount of clutch material in the bellhousing, this could have been a hint for them to pull clutch off and inspect it. Even though you only went in there to rectify a leak.

What style clutch is it and is there any signs of it having oil on it, from say the rear main or somewhere else?

Does it also look like they could have pulled the box up onto the back of the motor with the bellhousing bolts instead of getting it to sit on the dowels. If you can look at it yourself look for damage on the motor side of the bellhousing where the dowels sit, look at the bolt threads for damage, look at the bolt heads for rattle gun use IF they pulled it up with the bolts. The workshop the car is at now possibly could have seen it. Possibly throw some pictures up IF there is any damage so we can look.

It sounds to me the previous workshop was just plain rough thats all, i've seen a lot of cowboys do some stupid stuff like that.

[Dobz]

If your spigot bush is shagged the vibration should go away when you put the clutch in whilst travelling at speed.

[turboedsloth]

Not with the brass spigot bush in the back of the crank it wouldnt, the throw out bearing on the input shaft yes possibly

[Dobz]

A stuffed throw out bearing wouldn't cause any vibration in the driveline anyway. And yes if the bronze spigot bush has too much clearance between it and the input shaft it will cause vibration by throwing the clutch plate out of balance when it engages.

My brothers car had a tempremental vibration that only happened when the clutch was engaged under acceleration and went away when he took his foot off the clutch and smoothly engaged it whilst cruising at speed. Long story short we pulled the gbox and found the spigot bush stuffed, replaced it and fixed the problem.

[CeJay]

Is the spigot bearing or the input bearing shagged? Or even the input shaft? When the other workshop pulled the box out last time if they were any good (which from your first post im guessing they arent) they would have seen if there was a large amount of clutch material in the bellhousing, this could have been a hint for them to pull clutch off and inspect it. Even though you only went in there to rectify a leak.

What style clutch is it and is there any signs of it having oil on it, from say the rear main or somewhere else?

Does it also look like they could have pulled the box up onto the back of the motor with the bellhousing bolts instead of getting it to sit on the dowels. If you can look at it yourself look for damage on the motor side of the bellhousing where the dowels sit, look at the bolt threads for damage, look at the bolt heads for rattle gun use IF they pulled it up with the bolts. The workshop the car is at now possibly could have seen it. Possibly throw some pictures up IF there is any damage so we can look.

It sounds to me the previous workshop was just plain rough thats all, i've seen a lot of cowboys do some stupid stuff like that.

Current shop has said nothing about the spigot bush or input shaft being the problem. I don't think either should, as the input shaft was replaced with an r33 item at the time of the rebuild.

The vibration only occured when the car was underload. There was no vibration when in neutral or with the clutch engaged.

I had thought it was a stock rebuilt clutch, modified ala Jim berry style. It's a push type gearbox and clutch. I'll ask the shop if they noticed any other signs of damage on the bellhousing. The shop has taken a full set of pictures for me and has set the old clutch aside. Previous shop told me they didn't inspect the clutch or take it off. Clutch wasn't slipping at all.

Current shop has advised me they had no issues taking the tailshaft out, and they didn't think the tailshaft was too long, they installed the gbox and tailshaft in the first place. I am a bit suprised that this being the third time the gbox has been out in 4 months, that a stuffed clutch was only picked up now, I had thought that was something a shop would look at when the gbox was out. For the simple fact they could charge me for more work etc.

[CeJay]

Shagged clutch, shagged flywheel

Supposedly all 4 diff bushes torn/ stuffed. Shop up in sydney I had it at appears to think the car was thrashed. Car still needs work done to it as vibration is still there and not all work could be done before christmas. Only had two bushes replaced. Cant look at the car myself as it is still up in sydney.

[turboedsloth]

is that a lightened stock flywheel?

[CeJay]

I'm pretty sure it's a stock flywheel. I do have some more questions for people here if they can help.

In regards to a one piece tailshaft is there supposed to be play in the tailshaft? ( back and forth?)

If so how much (20mm ?)

If the tailshaft is too long can it damage or perish the pinion bearing in the diff? Ie by putting pressure on the bearing? ( I have been told by a shop my vibration may be the diff going)

If the vibration is there when the clutch is engaged as well I take it that points to a diff or tailshaft issue