Pinpointing a driveline vibration...

[thechuckster]

arvo = afternoon

[oldcorollas]

Bad & broken & worn mechanical parts don't usually get unfucked after they've gotten fucked up and they aren't going to work intermittently for very a long time if any time at all, while some electrical parts will.
Otherwise I'd only think it is something electrical or placebo effect or from different road harmonics & surfaces.

i've had "intermittent" vibrations from loose bolts on drivedhaft before.. but if something is bent or busted permanently, it should happen all the time..

sometimes if a piece of clutch friction plate is breaking off, it can have intermittent vibrations, depending where it gets clamped when you release clutch...

[sillycar chick]

Is this only happening on one particular road? Weather change from dry to hot & humid, or something else?
Bad & broken & worn mechanical parts don't usually get unfucked after they've gotten fucked up and they aren't going to work intermittently for very a long time if any time at all, while some electrical parts will.
Otherwise I'd only think it is something electrical or placebo effect or from different road harmonics & surfaces.


arvo What is arvo? Why would anyone ever give a fucking shit whether it is 'arvo'?

I cant see a pattern, it doesnt seem to happen on the same roads, it seems like it just comes and goes when it feels like it, though I do think its there all the time, just sometimes the vibrations are small, othertimes they get quite large. Vibrations can be intermittent, particularly where harmonics are occurring.... Harmonics could explain some of these fluctuations, but its still hard to tell from the small amount of time ive spent driving the car....

yes arvo = afternoon, I dont know why anyone would "give a fucking shit" whether its arvo, i was merely giving people a timeframe so they had more info to go on in helping me solve the problem. Though I dont see the need for comments like that, this is a technical thread....

[sillycar chick]

sometimes if a piece of clutch friction plate is breaking off, it can have intermittent vibrations, depending where it gets clamped when you release clutch...

wouldnt that then mean that you'd feel the vibrations particularly strong at the time that clutch is clamped in that position, without fluctuating, between gear changes?

[Mr*Beach]

If the vibration changes between accelerating and decelerating I would be looking more towards the diff. Such as worn carrier bearings or the like . Or loose carrier bolts ( not sure what diff. you have ). Maybe incorrect clearence between the crown wheel and pinion gears.
Knowing for sure if the vibration is related to engine speed or road speed would narrow down the diagnosis a lot. But then again, I haven't driven the car so don't know how easy it is to tell.
I would be very interested to hear the cause when you do eventually work it out.


Good luck
~Josh

[oldcorollas]

wouldnt that then mean that you'd feel the vibrations particularly strong at the time that clutch is clamped in that position, without fluctuating, between gear changes?

yes.... i guess it would.


good points Mr beach.

can you give the driveshaft a wiggle and see if there is more movement than normal?

[allencr]

Yes, sorry about the stupid crudeness.

wouldnt that then mean that you'd feel the vibrations particularly strong at the time that clutch is clamped in that position, without fluctuating, between gear changes?

It would mean that you'd feel it from startup to shut down, completely independent of driving, only dependent on engine RPM and that it wouldn't change whenever the disk is spinning, only after it is stopped & operating the clutch that will let gravity change its position.
OK, maybe/also having a load on that mickeymouse hub & spring/pad setup in the clutch plate/driven disk is shifting it around, with varying degrees of luck in getting it centered & balanced?? Is there any noise from the clutch area when going from engine driving the wheels to wheels driving the engine, like engine braking/over run or parallel parking, and ignoring any sound/s from the diff?

[sillycar chick]

Nah im not hearing any noises from the clutch at all.... or the diff for that matter
It might make it easier to find if I had a noise to go by, but theres nothing at all

OC I have checked for play in the diff where the driveshaft bolts up to it, theres nothing there, but I havent checked the gearbox output shaft. The diff has been pretty crap since I got it, it has too much backlash so when you drop the clutch too quickly you here a clunk... However there are no other noises, and it was driving fine otherwise. I was going to have a fiddle with the car at some point today as im not working, so i'll have another look at the diff.

I have considered the diff and have a spare one thats in reasonably good nic in the purple car, so i might end up doing a swap yet.... just really wanted to pinpoint this before I did any un-necessary work cos I dont have all that much time on my hands, but I might have to go that way....

[Alex63]

Something simple to check which caused me to have similar vibrations is the mounts for both Gearbox and Engine. At low speeds and unloaded you wont experience much vibration with a broken mount - you'll even get a speed where vibration nearly goes ( harmonic).
Make sure you get in there and aply leverage to check thoroughly - my bolt tore from the rubber and to look at you couldn't pick it.

Good Luck.

[Rosie]

Didn't want to start a new thread but did this get sorted, have very similar problem after i lost / sheared the tail shaft bolts off near the diff yesterday.

Probably did about 5 k's with 2 missing and 2 very loose bolts before i put temporary bolts in and did about 30k's to get home still had vibrations but was better (obviously) just thought vibrations were from different bolts.

I replaced all the bolts today and still have vibrations at 80kmh+ only noticeable with road speed not engine speed and only over 80.

oh and ra28, 1G and VR diff 3.7lsd. new centre bearing and diff has done about 2000k's since build, 2 piece tailshaft - was smooth as before bolts went.

Thanks Rosie.