Gearbox Vibration

[ClutchBurndout-:(]

Hi all, when in low rpm (usually after changing gears) i get really bad gearbox vibration, i have to rev past 3k (in first gear) so when i engage the next gear it doesnt vibrate, which you can understand makes baby jesus cry in the morning when the car is cold. it does this with all gears if the rpm is low enough, but as the gears raise the vibration is easier to avoid since raising the rpm to change gears isnt as painfull.

the vibration goes away shortly as i raise the rpm but it is quite bad and even loud through the car.

ive had the same issues with previous skylines, but the vibration was easier to avoid and you didnt have to rev as high to avoid vibration in the next gear.

any ideas what it could be?

Edited January 24, 2011 by Clutch

[chiksluvit]

happened to me a couple of times, first time was sagged gearbox mount, changed the mount and it was fixed

second time wasn't that bad, it was due to the mechanic not alligning the drive shaft on the rear diff correctly when he reinstalled it after changing clutch. the shaft is balanced with the diff so it has to go back in the same way as it came out

while most people would say that drive shaft issue should only be speed dependent, i can confirm that the rattle was rev/load dependent, not speed

[ClutchBurndout-:(]

happened to me a couple of times, first time was sagged gearbox mount, changed the mount and it was fixed

second time wasn't that bad, it was due to the mechanic not alligning the drive shaft on the rear diff correctly when he reinstalled it after changing clutch. the shaft is balanced with the diff so it has to go back in the same way as it came out

while most people would say that drive shaft issue should only be speed dependent, i can confirm that the rattle was rev/load dependent, not speed

ok, at least they are 2 semi easy problems to look into.

which gb mount are you referring to?

and how are you supposed to know how to align the drive shaft? or can only a mechanic do this?

[89CAL]

Tailshaft should be marked when removed so it can be installed back into the same spot

I guess the driveshaft can only go on 3 other ways but if it hasn't been taken off since it started doing this it's more likely to be another problem

[chiksluvit]

The worn gb mount was a worn standard mount sitting right below the gearbox, there's only one

Changed to polyurethane and worked fine. New car now has an ok standard mount so never bothered to reuse the polyurethane mount

Drive shaft wise if it wasn't marked on disassembly, you'll just have to rotate it and drive around, if not fixed then come back and rotate it again to match the next hole

[ClutchBurndout-:(]

The worn gb mount was a worn standard mount sitting right below the gearbox, there's only one

Changed to polyurethane and worked fine. New car now has an ok standard mount so never bothered to reuse the polyurethane mount

Drive shaft wise if it wasn't marked on disassembly, you'll just have to rotate it and drive around, if not fixed then come back and rotate it again to match the next hole

ok great, ill try a new mount. where can i buy new rubber for the mount?

for the driveshaft, do i just unbolt at the diff and rotate it there?

Edited January 25, 2011 by Clutch

[chiksluvit]

you can get nismo transmission mount, stiffer yet not as harsh as polyurethane, plenty of places have them, justjap or even ebay..

a cheap/free way of doing this is to reuse the original transmission mount by squeezing oversized rubber hoses into the gap and cable tie it in, i've tried this on a couple of cars and it worked great, if you still have the standard transmission mount it would've been pretty worn by now, so even if this wasn't the cause of problem it will become a problem sooner or later

rotating the driveshaft is just like what you've said, unbolt at the diff end and rotate it from there, there are 4 bolts, but make sure you mark it before you do anything in case that isn't the problem

if none of above fixes the problem, then its a worn centre bearing of the shaft which i dont think is serviceable.. means new driveshaft- unique autosports sell a one piece item which is reasonably priced

[ClutchBurndout-:(]

you can get nismo transmission mount, stiffer yet not as harsh as polyurethane, plenty of places have them, justjap or even ebay..

a cheap/free way of doing this is to reuse the original transmission mount by squeezing oversized rubber hoses into the gap and cable tie it in, i've tried this on a couple of cars and it worked great, if you still have the standard transmission mount it would've been pretty worn by now, so even if this wasn't the cause of problem it will become a problem sooner or later

rotating the driveshaft is just like what you've said, unbolt at the diff end and rotate it from there, there are 4 bolts, but make sure you mark it before you do anything in case that isn't the problem

if none of above fixes the problem, then its a worn centre bearing of the shaft which i dont think is serviceable.. means new driveshaft- unique autosports sell a one piece item which is reasonably priced

thanks mate your very helpful.

if the above 2 efforts dont work (which ill be trying soon) then i may try a new driveshaft, ive heard problems with the one piece driveshaft, are they that bad? whats the difference between 2 piece and 1 piece?

thanks again

edit, i tried searching for unique autosport, i only found the american based site, could you post their link?

Edited January 26, 2011 by Clutch

[chiksluvit]

i'd try the gearbox mount first, this sounded like the exact same problem i had when my gb mount was worn

not sure about one piece shafts, as i've never used/ installed one before, so i can't really say anything based on personal experience.

one piece shafts are harder to install but it lacks the centre bearing so one less thing to fail, and transmits power more directly in theory.

there might be other downsides but i'm not sure, since i've never looked into this, maybe someone else can shed some light

unique has a few web addresses, one is www.nismo.com.au

[ClutchBurndout-:(]

thanks for that

can you get the bearing repaired if it is the center bearing? or is it a throw out item?

[chiksluvit]

actually

http://www.skylinesaustralia.com/forums/topic/351451-what-tailshaft-are-you-running/

seems like it can be replaced, and that keeping the 2 piece is the way to go

just check your transmission mount first before you investigate this further

[CeJay]

stick with a two piece tailshaft. Nissan charges around 1200$ for a new one.

[ClutchBurndout-:(]

well last night i took the mount out, and to my surprise it was still in good condition... i put some hose in the gap anyway, it didnt make any changes

so whats the next step?

[chiksluvit]

then rotating drive shaft

have you had a clutch change? if you did, did this noise only occur after the clutch change?

if not then i'm out of ideas.. anyone else?

[GTRPowa]

1 piece have a tendency to warp under load, which will feel imbalanced, when you let off the throttle they go back to normal. This is why lots of manufacturers use 2 piece designs, because for most other reasons, a 1 piece would be better.

[ClutchBurndout-:(]

ok will try rotating the drive shaft next time i get some time

[simpletool]

Worn surfaces on the input cluster gears in the gearbox. I have this problem on my car. Replaced the mount with Nismo item gave me much nicer gear change feeling and faster changes BUT didn't fix the vibration issue - at all.

I've been told by a couple of gearbox places that it is the surface on the input cluster gears in the gearbox.

[chiksluvit]

guess i was pretty lucky to fix the issue with just the gearbox mount...

good luck with it and let us know what the outcome is

[Birds]

Worn surfaces on the input cluster gears in the gearbox. I have this problem on my car. Replaced the mount with Nismo item gave me much nicer gear change feeling and faster changes BUT didn't fix the vibration issue - at all.

I've been told by a couple of gearbox places that it is the surface on the input cluster gears in the gearbox.

If this is the cause then you will not experience it in 4th gear, given it is a direct drive bypass of the cluster shaft. But yes, pitting on the gears can certainly cause vibration...more commonly it's a bearing issue thought, particularly when it's affected by load and engine speed. I daresay OP may have a worn input shaft bearing or spigot, which are both directly affected by engine speed regardless of gear you are in.

[Nee-san]

just as an offside birds, i have a slight vibration between 2000 and 3000 RPM which goes away after this range, it also occurs in neutral, any thoughts ?