Weird rubbing noise when hard accelerating?

[legobumb]

I changed out my suspension on my 325xi a couple months back, and everything was hunky dory again for a while, but for the past month, whenever i hard accelerate in first and second gears, at around 3k RPMs, i hear and feel a vibration coming from the back of the car. I think it's the rear passenger side specifically. I'm unsure if the tire is rubbing the inside of the well during these hard accelerations, but then the RPMs wouldn't really matter if that was the case. It's definitely like a low tone as if it were the tire rubbing, and a pretty rough feel like like lugging the engine in a too low RPM range for the gear it's in.

Any recommendations would be awesome. I'm going to try to see if there is anything in the wheel wells that may be protruding when I can and I'll come back with a reply stating whether or not i find anything in that regard.

[dworthy]

I would check the center support bearin out first, as that thing tends to make the noise you are describing. It it is good, then continue to follow the driveline back to see if anything else maybe amis.

[legobumb]

Is replacing the center support bearing an easy task or does that thing going bad usually mean the dreaded subframe cracking issue?

[dhurley34]

Its a mildly complicated task for a novice. Requires a little marking beforehand to keep things balanced and no, it has nothing to do with the subframe.

[legobumb]

Yeah, i watched a couple videos on people replacing their center support bearing. It's a little odd to have the drive train in two pieces like that, but whatever i suppose. It seems pretty simple. Just a bit longer of a process due to having to drop the exhaust (or at least move it out of the way), drop the heat shield, then finally drop the drive train and replace the bearing. I can definitely get that done. I might consider replacing the U-joints while I'm at it.

[dhurley34]

U joints are not serviceable.

[legobumb]

U joints are not serviceable.

What do you mean? I've seen plenty of videos of people changing out the U-joints on their drive trains. Is the BMW one completely sealed somehow?

[dhurley34]

Yes. They are "staked" in and cannot be removed and replaced without considerable fabrication.

[legobumb]

That's incredibly awful design if you ask me. But thank you for the information.

[dworthy]

Like the newer car headlights, you just cannot replace anything anymore on a BMW. Now if you are looking at getting the driveshaft rebuilt, I would recommend contacting these folks: http://www.driveshafts.com/products/...ed-Driveshafts

[Jackson42]

BMW U-joints have always been staked, going back as far as the E12, in my experience. And they don't wear out very easily, either. This is just one of those facts of life that you accept if you intend to keep your BMW beyond its design service life (seven years or so). Most good driveline shops have the expertise to rebuild these driveshafts.

[dhurley34]

I have seen several u joints on the E46 start to show rotational play around 100k. The joint closest to the diff wears out the most.

[legobumb]

If I notice any worn out U joints when i replace the center support bearing, I'll definitely look into replacing the drive shaft.

[Honolulu]

But hey OP, it's a week later and it sounds like you've done "something", so is the "rubbing" sound still there?

I think the suggestion to check the CSB is a good one, but sometimes noises can fool you. If you haven't been under the car yet, add to the list to check the rubber guibo or "donut" that sits between the output flange of the trans and the front of the driveshaft.

I've got the same car, same year. When I bought mine there was a periodic "grunch" in the front that was speed variable. Nothing visibly wrong until I took off a front tire and found a deep crack all the way around the inner sidewall. Both tires. Looked like they had both been run flat, though the PO denied it. Car was filthy but cleanable, got it for $500 with 97,000 on the clock. PO had lost the key and ownership papers then got "tired of having to take care of it" ... as if he did anything other than fill and drive. Nice car after cleaning, new tires, a left halfshaft, but at six foot six, I don't fit, so my normal-sized daughter drives it and we're both happy.