2001 sl2 whine noise over 40 mph

Ok.....so my 5-speed, 2001, sl2 has been making a whine which is noticeable at around 40 mph and pretty loud and constant cruising at 70 mph. I originally thought it was my tranny, but figured I'd drive it till it quits and then replace. However, I've noticed that the noise is not affected by pushing in the clutch, changing gears, hitting the gas or breaks, etc.. It is constant and does not fluctuate, and is coming from what seems to be the front of the vehicle. I'm guessing now (and I truly mean GUESSING) it may be wheel bearings or axles? Any advice here would be GREATLY appreciated.

Possibly a wheel bearing. At the same RPM, does this noise happen at idle?
Does the noise change with turning of the steering wheel?

One test is to put the fron of the car on jack stands and have an assistant get the car up to 40mph with which ever gear the noise happens at. Then see if you can isolate the noise better.

My guess is that its just the carrier gears in the differential. Tho they arent supposed to make noise, they sometimes do.

Tranny Fluid alright?

It's a manual transmission. Tranny fluid?

It makes the whine regardless of what gear its in, noticeable around 40 but pretty loud at 70 mph, and it doesn't change when i shift or push the clutch in, just remains constant then winds out as the car slows down.

I'll do a quick test drive and see if the noise changes when i turn the wheel. Will post back in a bit.

Thank you VERY MUCH for responding and spending some time on this. Greatly appreciated!!

Yup...gets significantly louder when I turn the wheel right, so I'm guessing driver side front wheel bearing?(Had an interesting time trying to find a spot where I could turn right at 40 mph)

If this is the case, how difficult is it to replace, and should I replace anything along with it?

Wheel bearing!
Put the car on jack stands and turn the wheels. Youll be able to tell which is the problem. I would think you are correct that its the drivers side but double check :)

Wheel bearing can be bought at the auto store. Not to expensive. However, it must be pressed into the hub. So the entire spindle must come out and be brought to a shop to have the old pressed out and the new put in.

If you would like I can expain how to remove the spindle. I can post a how-to however i dont have pictures :/

its not a very hard job at all. Youll need your basic metric set (impact is best), a 30mm socket, breaker bar, and a nice long pry bar. A sludge hammer and PB Blaster is always helpful also :)

Thanks for the info. Now, the wheel bearing is 30 bucks, but timken also sells the entire wheel hub assembly for 50 bucks....so I'm thinking it would be easier and most likely cheaper to just replace the whole hub assembly, right?

Is my thinking logical here, or am I missing something? I'm no mechanic, but I can fix most anything, and it sounds easier to just remove and install the new hub assembly, without having to get a shop to press the bearing for me.

Thanks again for the help...it's definitely easier on my mind to rule out a new transmission (and easier on my WALLET). I've had this car for about six years, and love it. And at 32-36 miles per gallon, I was really hoping not to have to sell it soon.

Thanks again!

In most cars, yes that would be the way to go. However, the hub is pressed into the spindle also. The bearing is then pressed into the hub.

The easiest way to go would be to fine a spindle with low miles on it. Thats what I did. Had the car back on the groun in 30 min :)

Just wanted to post a quick thanks for the great advice. I changed out both front bearings and hubs last weekend, and now the car runs smooth as ever. So excited that it wasn't something serious...I was playing with the idea of selling it, but at 35 mpg....I'll hang on for a while.

Thanks again for some truly professional advice!

Fantastic! Glad you got her going again. Sell it!?! Keep her forever!!! :)

As you can see by my signature im a big s-series fan :iceslolan