Weird Resonation / vibration from gearbox

[Kdawgboostin33]

Hey Guys,

Gotta bit of a problem. I have this vibration / resonation coming through the gearstick lever and under the car. Thought it might of been the Tailshaft but have replaced that and to no avail. Anyone have any ideas cos I am really running out of ideas.

Thanks in advance

[JimX]

Have you checked the engine mounts and bolts that hold the box to the engine? Even though the tailshaft was replaced, it might not have been balanced properly. Also did they use good quality universal joints?

[Kdawgboostin33]

Hey Jimx,

All I did was replace it with a series II tailshaft. But after having the box out a few times, it temporarily went away for a few days after it had been out. But then it started again after the few days

[«Cyph3r»]

Did u use loctite on tailshaft bolts into diff? Other than that i have no idea?

[Cubes]

I've got a similiar problem over 90km's, when in 5th gear only.

Under hard acceleration the vibration can't be felt, its only when lightly coming on and off the accelerator.

I've put it down to the gearbox. ?!? It does whine a bit.

[Steve]

Have you been bumping any gutters? Perhaps (I know its a long shot) it is wheel balance?

[Leadfoot]

I am the same as -Joel-

Mine is a 1996 GT25ST series II with 65,000kms (hopefully). Vibration only occurs in 5th gear as well. It is most noticable when either accelerating or decelerating. Neutral acceleration is quiet.

The reason I believe is that 5th gear (or overdrive) uses a second gear-rail

in the gearbox not used by any other gear ie 1st to 4th. The second gear rail does usually not have as good bearings and such can become noisy as the end float increases with general wear.

Overdrive is usually the weak point in any gearbox and for that reason most manufacturers never recommended towing in this gear. I am not too worried as a I have a borg warner T50 in another car with the same noise since the last 100,000kms. The fix is to crack open the box and shim the end float to manufacturers tolerance - very cheap fix but time consuming.

I am going to change the oil to see what happens.

I would be interested to hear at what odometer reading -Joel-s and others cars have started making the noise.

[Cubes]

Its definately a gearbox issue.

Darren (Bl4ck32) has recently dropped a RB25DET g/box in to his R32.

The box is stuffed. It has the same vibration mine has in fifth but worse and its in every gear.

Mine started making the input shaft bearing noise around 70,000km's. Just after I bought it. Its still making the noise to date and the car has just clocked over 167,000km's.

The gearbox is starting to get a little loose now as when in Mc Donalds for example and riding the clutch you can hear a rattling noise from the g/box.

The box has held up really well.. If it went now I wouldn't be sad.

The VS 5ltr 5 Speed g/box I had was absolute crap.. It had the same symptoms but crapped its self within 20,000km's from when it first started to make a little noise.

I had it rebuilt then around 10,000km's later the rattle from the box came back.

Its actually the lay shaft needle roller bearings that cause the rattling.. Thats providing they are setup the same as the old 4 Speed Single rail g/box's I used to rebuild.

The rattle sounds exactly the same as the 4 speed single rail box gets when its lay shaft bearings are stuffed.

[Leadfoot]

Thanks Joel,

Its good to know that I can expect another 100,000 kms!

I might slip in some heavier weight oil like redline shockproof

heavyweight though, just to see if it doesnt make the 5th

gear a little quieter and take up some of the the slop in the

lay shaft bearing.

It sounds as though getting secondhand box is a waste of

time if its done over 60,000 kms, thats if your looking for a dead

quiet gearbox anyway. I am considering reconditioning if the noise

starts up on all gears. For now, I think it was either making the

noise when I bought it (4 weeks ago) or it has just started.

Do you think it is possible for someone with the typical garage

tool setup to strip and repair a RB25 DET box??

Apparently fitting OS Gikken parts is not as simple as it sounds

as double synchros have to be fitted and not cheap either at around

$4,500 a set.