My mini r50 has developed a strange humming noise while driving. Checked the usual suspects, ties seem fine and not a wheel bearing problem, is also seems unlikely to be the transmission as it is smooth through the gears and the noise remains even when in neutral.

Any help or suggestions would be great

 

Curious.
With the engine running, in neutral and parked is the humming noise still present?
While the car is parked in neutral, and engine running, (parking brake on for safety); Have you tried crawling/looking under the car to see if perhaps either your power steering pump is running constantly or (even the off chance) that the power steering fan maybe running all the time?
In my limited experience (especially with an R50); I wonder - Sometimes a failing belt tensioner pulley will exhibit some strange noises before detonation.
Not sure about an R50 though.

 

The noise is only present when moving which is really bizarre, I have booked it in for a health check up this weekend so hopefully will get some answers. I'm thinking maybe I haven't checked the tires properly, but I'm sure that will get picked up if that's the issue. I have not checked the belt tensioner will have a look tomorrow

Thanks

 

Has a small leak of transmission oil, so is probably low is there any common causes for transmission leak?

 

Nope, no common issues there. The oil is so thick the fill and drainplugs actually don't need a crushwasher.

Was it actually only leaking from down there or could it have been from higher up? Like power steering or rear main seal oil escaping from the flywheel dust cover.

 

not sure when I top up the transmission oil i will give it a clean up and then see if i can locate where its coming from

 

If the belt tensioner was the culprit it should make the noise when revved a little parked in neutral. I suspect right side axle support bearing, is it speed dependent? Does the pitch in noise change with speed? Is it louder at certain speeds or during cornering etc...?

 

So the transmission was full of oil and not leaking, the actual culprit of the leak was no gasket for the engine oil filter housing. The noise appears to start at around 25 mph and then doesn't get louder with
RPM or cornering, so maybe a belt. What's an easy way to diagnose a faulty axel support bearing?

Also, what is a good maintenance scheme for the transmission/ how do I look after it as it's the OEM transmission and the car has 106,000 miles.

 

Idk of an easy way to diagnose that support bearing if it's not physically loose, other than trying to rule out most everything else. The axle is fairly easy to change and not very expensive. I bought one for my car and then proceeded to convince myself the noise wasn't that bearing, it ended up being primarily the upper engine mount but in the end it was the axle bearing too. It appeared normal when shaking it etc... but prob had scoring or rough spots.