Ive a 2006 R52 Justa with 5 speed. Its got 163k miles and has recently started to make noise thats basically a fast ticking / rattling sound. It started a couple of weeks ago, only heard when under power in 5th gear at 70mph, but has since progressed to making the "tick" at speeds above about 35, in any gear, or in neutral, with or without the gas peddle.
Heres a couple of youtube clips for the sound at about 35 with some gear shifts, and at 70ish on the highway. Anyone recognise this sound?

The CV shafts were both replaced about 1000 miles ago and to my uneducated eye look and feel fine still. The tick is independent of engine speed, but below 30 mph it seems to stop. Hard to tell while driving if its associated with one particular side of the vehicle or not. Ive jacked it up and had a look underneath and there is nothing obvious, no torn boots, doesnt seem to be play in the wheels. When I rotate the wheels there does seem to be some sort of metal clank noise from the "final drive" where the drive shafts are inserted into the transmission, but I dont know if some sort of noise is to be expected there when rotating the wheels by hand back and forth.

I dont want to sink a ton of money into diagnosing and fixing it, but its got progressively worse over the last couple of weeks so I need to do something. I'm worried its some sort of final drive bearing in the transmission but have no idea how to go about isolating that as a diagnosis. Any help with pin pointing the cause of this would be fantastic! Cheers

 

There is a little slack in the trans when you rock the wheel back and forth, but should only be a little (hard to explain). The sound doesn’t sound like CV joints. It sounds related to timing chain or too end engine maybe.

 

Thanks for the feedback. I get maybe a 1/8 turn of the wheel, in fact probably not even that much. Didnt really monitor it too closely. Maybe 6 inches of travel or so?. Ill recheck later. It does sort of "clack" at the end of that travel.

It doesnt vary with engine speed, I can thrash it in 1st gear and it doesnt make the sound (well, not yet anyway...) The rattle / tick is the same at 70mph whether in 4th or 5th gear. The Frequency of the rattle varies with wheel speed independent of engine speed if that makes sense?

 

To check you CV joints jack the front up and put it in gear. Then try and rotate the wheels there shouldn’t be any slack or very little movement. Grab the axle in the middle on the shaft and try and wiggle it back and forth and in and out inline. There should t be any movement or no more than about 1/8” movement.

 

I’m getting about 1/8 in and out on the longer passenger side cv joint. As I rotate the wheel there is an ominous clank from the transmission. Any one heard this before and know what the cause is?

Clank while turning wheel

CV motion

thanks...

 

The slack does not appear to be CV joint related. The lash in the trans when you rock the wheel also does not seem excessive for 163000. Are your CV boots intact? Have you driven it in a parking lot in tight circles to see if you have popping noises in the joints? Your original video still sounds engine related especially since it increases with engine RPM.

 

CV joints look and behave fine i think. In one clip the speed is also increasing with engine RPMs. When I drop from 5th to 4th on the highway the noise stays constant, Im pretty sure its not engine related..

Only "easy" thing I haven't checked yet is oil level in the transmission, but there is no external sign of a leak.

 

Well, its fixed now. In case anyone else has a similar thing going on here's "the rest of the story":

Turned out to be two things going on, the noise got progressively worse until it was doing it around 20mph at which point I took it to the shop. Occasionally after that it would go quiet every now and then, and then start up again a few minutes later.

At the shop they diagnosed a rumble that was the dreaded pinion gear bearing wear which is a common end of life mode for these old first gen cars. I am told the box itself is not all that hard to work on but you cant get "new" parts for these 1st gen Getrag boxes only whole replacement transmissions ($$$$). Well, I tracked down a reconditioned 5 speed pinion gear (remachined with hardened sleeve added) and a bearing and seal kit online and arranged to take it back in once it got a bit worse. I should have bitten the bullet and got the rebuild done then, but my guy said it wasnt as bad as many he had heard and to keep driving it till it broke, or at least got unbearably loud. Unfortunately one morning a few weeks later I was greeted by the sight of my Mini sitting in a puddle of very dark metallic transmission oil as it had dumped its load on the garage floor overnight.

Turned out that the rattle featured in the videos was caused by a carrier bolt head that had sheared off the main ring gear rattling around in there. Eventually it punched a hole in the transmission bell housing. My shop happened to have a discarded Getrag 6 speed bell housing laying around the shop (its the same case for both), which saved me a few bucks, and while we were in there we replaced the clutch which was starting to separate in the center.

So, this wouldnt have been first choice for what to spend my recently arrived tax refund on, but it was a little cheaper than replacing the whole box, or even the vehicle, and at least now I know the history of the clutch thats in the car

If you happen to be in Upstate South Carolina when your transmission dies, I can happily recommend the work of Leon and his guys at Advanced Transmissions in Mauldin, hes been doing this for years and really knows his stuff.