Hi everyone,

So my mother recently got a larger vehicle and gave me her old Mini to have as a spare car. I've kept the car up since she got it and always really liked it. It's a 2005 R50 base Cooper with the CVT transmission and around 130k miles. Not exactly toping the list of most valuable/desirable modern Minis, but it's in nice shape and runs well. I'm going through and freshening it up since it's showing its age a bit. Mechanically, everything is tip top and normal, except for the noisy CVT.

The CVT has always driven and shifted really well, but it's also always been noisy. I determined a while back that the noise isn't related to the belt, I'm 99% sure it's a bearing noise. It's a humming noise that only happens when driving, and is only really noticeable over 25-30mph. By 65-70mph, the noise is kind of loud, but it's steady and directly related to wheel speed. I have found when I am getting off the freeway on a right curved ramp, the noise will stop when weight gets put on the left side of the car. I started looking again recently and found there's a lot more info available on the CVT's than just a few years ago and that we can actually get parts for them now. I'm not opposed to dropping the transmission out and opening it up if needed, but I want to get some more info before doing such to an otherwise working transmission.

I've searched a few different terms and mostly found older threads regarding failures. But has anyone installed one of the new third party drive belts into their CVT during a rebuild? I see now you can get them on Amazon for $100-$150 shipped from a US distribution center. But it's hard to find any experiences with these belts long term. I would like to put a new belt in if I open the transmission, but I don't want to put one in that's even more of a ticking bomb than the original lol.

Also, does anyone have any experiences with a bearing noise like I described? Based on the CVT rebuild video, I think it might be the secondary drum bearing. I ask because I see this bearing and the main bearing are accessible with the trans still in the car. Wasn't sure if anyone had found a way to pull either of those and replace without removing and opening the trans. Otherwise any input on more recent CVT repairs is always welcome.

Thank you!

 

Just now read this. Did you figure it out yet? If not, are you certain this is not a wheel bearing issue?
From the way you described it, sure sounds like it could be.
If it's a wheel bearing that sounds like i'ts on the right side of the car, front or rear.

 

Thanks for the response. I was pretty sure we had ruled out a wheel bearing back when we first got it, but the details were hazy and I do agree it sounds like a wheel bearing, so I decided to recheck. Both front wheels off the ground and trans in Neutral, there was no play in the wheels in any direction, but I know that's not the whole story on these. I rotated the right side first and it was quiet and normal sounding, even rotating it quickly. Moved over to the driver side and immediately noticed it was noisy even at a slow rotation by hand.

I got excited it might be a wheel bearing, but I got my head up under the car as much as I could and the sound seems to very much come from where the driver side CV axle plugs into the CVT, which is where the suspected bad bearing happens to be. I didn't think of checking the rear wheel bearings for some reason, will definitely check those as well. But I'm afraid what I found today might confirm my CVT bearing suspicion. I didn't have any other tools around except my jack so I'm gonna try to double check and isolate the noise to that spot. I wonder if I might be able to get a puller on that bearing, if so it could definitely be swapped with the trans in the car.

 

First one to go on my car was the left rear. Could hear it was coming from the rear of the car but couldn't quite discern whether it was left or right. It became obvious when I removed it - completely wiped, binding and grinding. I ended up just replacing all four. Not nearly as hard a job as I thought going in, only took a couple hours total.

Safety first - would get a set of jack stands and put up all four corners. Not sure if CVTs stop the car from rolling in park (?). Especially one that may or may not have issues.

https://www.pelicanparts.com/techart..._Your_MINI.htm

Hopefully a CVT heavy expert will weigh in with the right insight if it turns out to be the bearing or anything else inside it.

 

Thanks for the info, yeah wheel bearings are normally a pretty mild job. The CVT behaves like an automatic transmission in that regard, they utilize a parking prawl mechanism and it wouldn't be affected from a crunchy bearing. No worries though, since I wasn't at my shop, I just did one side at a time to satisfy my curiosity.

I have since dug into a few diagrams and rewatched the rebuild vid a few times and realize the bearing I now suspect to be noisy is an internal bearing that's pressed onto its gear, no fixing that in car I'll probably just drive it and keep an eye out for another trans to throw in. I have a history of putting money into cars that will not return on the investment at all, so this feels about right lol

 

You might have been right to get out the popcorn, and I may have to eat some words. I got to my shop today and got the back of the car lifted. Driver side wheel was fine, but passenger side wheel is noticeably loose. Not horrible, but definitely not correct. It doesn't make much noise when I spin it, more of a squeaky noise, but I've read numerous instances of these bearings only being noisy under a load. Also goes along with why the noise quiets on a right turn ramp.

As for my "for sure" noise coming from the CVT diff area, it is indeed coming from that area, but it looks like it's just a failing CV Axle, found a torn inner boot and grease everywhere. Got both replacement parts ordered up, should be simple jobs. I will crap if I dealt with this noise for so long over something so accessible lol. Thanks again for the outside perspective, it was much needed.

 

Every person that i know either replaces the CVT new or goes with a 5 or 6 speed swap.

Only person i know that has done it on here and posted, this might help with tear down and how it functions: https://www.northamericanmotoring.co...built-cvt.html

Lots of the internals are not available from ZF.

 

thinking there's an easy way and a hard way to do this

 

I've not had a lot of luck with rebuilt cvt's. After the second swapout, I ended up buying a new transmission in box on ebay for around 1800 about a year ago. Still going strong.