[losfer]

A customer of mine (who might even be on this site?) has been chasing a vibration for some time in his jimny now . engine mounts replaced , uni joints replaced , driveshafts reconditioned and balanced (even the front cv end of the tailshaft) transfer and gearbox mount replaced , slightly bent left rear axle replaced , all of this done by the customer.

Today i had a look and test drove the car , vibration can be felt lightly at 35-40 kph onwards then escalates rapidly at 80kph + to the point where you can feel it through the floor the seats and the whole car . I removed his mud tyres and put standard rims and tyres on and the problem persisted . I replaced the jackshaft and dropped the tailshaft off the transfer and the problem persisted . when on the hoist doing 80 kph you can feel the vibration in the transfer but not in the gearbox . has anyone ever seen this before , as ive seen a lot of jimny's but never came across this .. its like half a gear is missing in the transfer (going by the vibration) , but it is quiet and problem free ?

as an edit , the transfer lever isnt doing any circle work , but its like a weird harmonic vibration that eminates through the whole car at speed...

[31zook]

Tried replacing the Tcase mounts?

[Scales]

is it anything to do with the chain in the t-case? just spitballing here...

do you have another case to try?

[losfer]

yeah sorry didnt i mention the t/case mounts were replaced? ok they were. edit , yes i did ...

we do have another case to try , which is what im going to "lend" to him to try himself to save himself some cash on my labour , i feel sorry for him as he's already spend a shitload chasing it himself . ive virtually narrowed it to the transfer myself , just cant comprehend what is going on in there to cause such a serious vibration when there is no evident problems with the transfer.

[christover1]

Time to rebuild case with gears.

Is the case stock?

[Scales]

if stock, its WT case time..... or find a donor jim case...

Did i mention i have a spare jim case?

[303zuke]

losfer wrote:

A customer of mine has been chasing a vibration for his jimny.

I have one he can have!

Seriously, a bit more background info might complete the picture. Year model and Kms? VVti or non-VVti (ie electric change or manual) case, any sign of metal bits in the changed oil, "always been there since he got it" and gradually got worse, or "it suddenly went BANG after I did *this*"?

My guess is a collapsed bearing. Unlike the LJ, Sierra, Vit and GV transfers which all use helical gears for the reduction (and which generate thrust forces), the Jimny uses planetary gears in a cage, which do not place a thrust force on the shafts. If a bearing fails in a helical gear case the thrust forces will make all sorts of racket and cause problems with gear engagement to indicate a problem, but in a planetary gear case there is no side loading on the failed bearing, or rather, the failed bearing is not required to control or retain any thrust force. The case can function normally without any apparent issue except that the bearing is not able to maintain the shaft on it's axis, creating an imbalance felt as vibration.

Either that, or he has chipped off some teeth from the 4wd engagement dog and the whole selector hub is out of balance.

[losfer]

ok it turns out its not the transfer after swapping it out with another transfer ..

[PORL]

Pretty sure I got a similar issue. How bad is the vibration? Mine very small above 80kms, almost feels like a unbalanced drive shaft

[losfer]

ok another update , after replacing almost everything , including the customer replacing the gearbox after a gearbox specialist told him it was a bent output shaft ....
it turns out it was the jackshaft that had the unis fitted and balanced by hardy spicer .

[atari4x4]

ouch, that sounds like it would have been an expensive elimination process.

[losfer]

I let him use our hoist and borrow parts for free for testing , so still cheaper than full blown retail arse raping , but yes he spent quite a bit .