r154 rattles at high revs. just started.

[bosslock]

hey guys my r154 gearbox makes a rattling noise when i hit high revs i noticed it in second gear yesterday. should i be concerned?
my clutch is pretty rooted also could this be the noise im hearing?/
thanks lads.

[convertableTA23]

Could be a number of things, could be bearings within the box or could be as simple at the throwout bearing rattling. When you hear the noise lightly put your foot on the clutch, just rest it there, if the noise goes it is the throwout bearing.

[bosslock]

ok will do. its only at real high revs about 7k

[1JZ-Rolla]

Or it could be a cracked flywheel, about to take your feet off

[convertableTA23]

yeah, or it could be any crazy problem throughout the drivetrain, no need to scare the poor fella
If the rattle is still there with your foot lightly on the clutch, stop, select neutral and rev the engine, if still there depress the clutch and rev the engine, if it stops then, it'll be the input shaft bearings. If it stops in neutral, see if it is there in all gears, if so it is the output shaft, if not it is the lay shaft bearings. This is of course making sure the rattle is deffinatly from the box, not any number of other drivetrain related things, could be exhaust, could be tailshaft, could be flywheel. Provided it is from the box area, the box needs to come out anyway, and just go from there. If it is from internal box, rebuild the whole thing, don't do a wrecker special and just replace the input or output shaft bearings (don't laugh, i have seen if done in a used car yard before).

[ajansen]

Or it could be a cracked flywheel, about to take your feet off

Personal experience?.. besides the whole no feet thing?

[convertableTA23]

Thought about asking this to, not all that common on street cars, i have heard lightweight race type flywheels doing this, but still now all that common.
A portion of flywheel making a new inspection hole in the bellhousing would be "hectic" (did i use it right???)

[1JZ-Rolla]

HeKtic indeed

Nah, fortunately never got that far, caught it early. JZA70 I bought though had fractures in the flywheel, seemed to be just from overheating the friction surface with the aggressive button clutch. Was enough to make it noisy and vibrate on clutch engagement (different symptoms to yours), I just thought the clutch was stuffed, but was glad I pulled it apart before the cracks got worse. Was an OEM flywheel too.

ConvertableTA23's assessment procedure above is spot on, methodically work through those tests and you'll be able to work out fairly conclusively whether it is gearbox or other drivetrain related. Thanks for filling in the gaps with constructive advice where I fell short mate Haha

[convertableTA23]

Have we got a result of the noise yet??????

Just keen to see how wrong i was