Grinding/squealing noise while slowly accelerating
 

Hi all,

this is my first post with my first "problem". I own 2001 X5 E53 with 4.4 engine - US import.

The problem is - it started yesterday and it makes it while cold mainly. It is doing with light foot on accelerator around 1500-2000rpm. The car is right after full service - gearbox flush with filter, transfer box oil, rear diff oil, engine oil with ALL filters, spark plugs....

Here some videos of the noise.... It's hardy noticeable when in car with closed windows. It sounds like brakes, but depending on engine rpm? It does only in D not in R or Neutral and only when the car sits for a while... When going away from city it dissapear...

While driving in the morning
https://www.youtube.com/watch?v=p2zR...e_gdata_player


When parking...
https://www.youtube.com/watch?v=bMqTaGfUF5Y

Thanks in advance... I just want to enjoy my new X5.

Where did you have the trans flush done? What fluid did they use?

LT71141 as from BMW manual.

Almost sounds like a bad bearing in a pulley. Pop the belt off and spin each pulley by hand. If it spins freely chances are its bad.

Going to garage tomorrow. When it warms up it goes away... Weird thing that pisess me off very very much. :rolleyes:

I had a failed bearing on one of the pulleys on my E39. Was super loud when cold. Once it warmed up it went away. Easy, cheap fix. (relative anyway)

Idler or tensioner pulleys are easy to check as noted above. If it spins freely, without resistance, it's bad.

My fan clutch sounded a hell of a lot like a bad water pump bearing when it was going bad.

Depending on which engine he has, he may or may not have a fan clutch. I know my X5 has an electric fan.

Little update - the sound does not appear when the car is on jacks - only rear wheels spinning and it´s quiet so it have to be something with front drive... I changed transfer box oil aswell no change... Here is new video I took... WTF!!! It appear only when going forward with light acceleration...

https://www.youtube.com/watch?v=bMqTaGfUF5Y

Can you find out what fluids they used when they did the fluid changes? Specific viscosities, types, and brand. Is it possible to tell if the noise is louder from the front or rear and left or right side of the vehicle? You may need a second person in the car to help identify a general area the sound is loudest.

I bought all the stuff. The garage did only the job - made many X5s... Done in less than 300km.

Fluid was FEBI ATF / LT71141 with MANN filter kit (filter, gasket, O ring)...

I think the noise is coming right below driver seat under the car - transferbox - but the sound doesn´t seem it comes from some lubricated area inside?

What about the differentials (front/center/rear)? If the noise is only present if the front wheels are spinning, then that eliminates the transmission as a possible source (for now).

Centre "diff" is transferbox am I correct? Rear diff oil changed aswell... Front diff not yet, but the noise is really under my seat from outside...

yes, center differential AKA transfer case. Maybe not enough or too much oil in transfer case? And what oil was put in the transfer case?

Changed today. It was low and dirty, but no change... Castrol DexronIII.

Have you pulled the wheels off, checked the abs sensor wheel, the dust boots on the constant velocity joints on the front axles, and other rotating parts?

That's a sound I haven't heard before. I mean it could be a wheel bearing, but I've never heard one that loud before when moving that slowly.

Going to garage again today so will take the wheels off and check.

Wasted 2 hours in garage. Checked everything that moves and all fine. I've asked 3 times my mechanic if there is right amount of oil in the gearbox and received 3 answers that the sounds doesn't have anything with gearbox. I'll just leave it and use it. Maybe it will get worse or dissapears. Don't know which way to go to find out. I'm tired. :dunno:

I was thinking center bearing on rear driveshaft, except it doesn't make noise if the front wheels aren't turning?

Will use the car for now and will look if it get worse/better... Will update the thread of course... Thanks for now. Much appreciated.

Noise is from front drive shaft spline connection
 

Zemi,

I am sure you gave up on the problem and/or sold the car, but for others who find this thread I am almost certain of the cause of your noise...because I had the exact same problem with my e53, 75,000 miles.

It is the front drive shaft spline connection which is why it sounds like it is coming right under the driver's seat. This connection is notorious and failure is certain and will leave you on the side of the road, 86 miles from home which is only a $500 tow away. (Can you guess how I know this?) The noise is caused by the dry and rusty splines moving in and out against each other as the flex-disk flexes. Perhaps attempting to lubricate the splines would cure the noise but may only mask the worn splines which will almost certainly fail...someday.

Check your spline for wear and replace with a modified (longer) drive shaft spline which can be welded onto your existing front drive shaft by a competent machine shop ($200 for part, $75 for welding). While you're at it replace the flex-disk for the front shaft.

Because of the now longer drive shaft (by 3/4") you will have to loosen your transfer case and slide back about 1/2" in order to put the new shaft into place. This is a royal pain in the butt and requires E-torx sockets and wrenches. (Note: you need to drop both exhaust and rear drive shaft to do this job.)

This should help: http://www.xoutpost.com/bmw-sav-foru...haft-pics.html