Strange clicking noise under hard acceleration
 

Hi all, :imnew:. I have a 2001 E53 4.4 with 150k 01/01 mfg date. When I accelerate hard from a complete stop I get a few loud clicks (2-5) then it goes away. It only happens from a complete stop, not when already moving, or above 10-15 mph. The sound is like a loud torque wrench and it comes from the front of the vehicle near the trans or diff maybe? Hard to pinpoint. I have just replaced both front cv axles with new ones and drained and filled both differentials with mobil synthetic ls 75-90 gear oil. Maybe it's the flex joint connected to the front diff? Or is it a trans issue? Broken input shaft? I have researched for hours and could find nobody else with this issue. Any help would be greatly appreciated.

Driveshaft from the transfer case to the front differential needs to be replaced or a longer splined portion needs to be welded on.

What ever is causing that popping sound, I wouldn't be driving the X like you stole it until you fix it. If it is the splines on the driveshaft you could be ruining the splines in the transfer case which will be a very costly repair.

I'll back trader4on this one. There was absolutely no warning when my front driveshaft splines gave away. I had just finished driving non-stop from Odessa, Texas to Arlington, exited the interstate and the splines went as I tried to accelerate from 20 mph to 35 mph. Initially, I thought the torque convertor had gone out. On disassembly, it was obvious that rust had developed on the splines for quite some time until they failed completely.

2002 X5 3.0 290,900 miles
2014 428i 12,700 miles
2004 325i sold at 123,600 miles
2001 325i sold at 66,000 miles

It's the chain. The driveshaft could also be wearing. I suggest replacing the chain and installing a longer driveshaft before it gets worse

I JUST started having this same clicking sounds when moving out of Park or from a dead stop OR sometimes noticed at very slow speeds!!

Update: talked with my mech and he told me its my rear driveshaft.

Thanks for all the replies! I think that it is most likely the transfer case chain. I will drain the fluid and inspect next weekend. When I am driving and I let off the gas for a second or two and then step back on the gas there is a sort of clunk, like slack somewhere in the driveline. This is what leads me to believe that the culprit of the clicking noise is the transfer case chain. I will most likely be doing the work myself, as I don't trust any mechanics but one.. and they are only slightly cheaper than the stealership. I am pretty mechanically inclined and have the tools necessary, although I don't have a ton of experience with cars. But hey, there's always something new to learn!

Depends on what length you get. I have read that you need to unbolt the tcase for the OE length +1 inch.

I had bought one that was OE+half an inch that, supposedly, you can install without unbolting the tcase, but stupid me ordered a facelift one which is too short for a pre facelift, I guess. I have a +1 inch on the way.


Here is my stretched out chain. It's hard to show in photos, but you can kind of tell how much slack there was.

http://i673.photobucket.com/albums/v...psy4ocyjpm.jpg

http://i673.photobucket.com/albums/v...psptio77ox.jpg

http://i673.photobucket.com/albums/v...psd5vrelz5.jpg

http://i673.photobucket.com/albums/v...psnawvidqz.jpg

And the difference between pre facelift and post facelift.

http://i673.photobucket.com/albums/v...psaxjjnf8c.jpg

Josh thanks for your updates, I assume you are doing DIY - nice work - I actually have an inkling my chain may have some stretch on it as well - if I let off the gas on the highway and then go to step on it so to speak, there is a half hesitation and the slightest bang, as if the chain is loose and slipping a bit - no clutch slip, and its not coming from the motor - Would be nice to fit a new chain and a new shaft and not have to repair any other items (i.e. letting the Tcase/driveshaft go until failure)

I thought about getting all new seals, but at $50 a seal I figured I'd wait and see what ends up leaking. It's not that difficult to remove the tcase with the right tools. I got that top driver side bolt with a swivel and a couple extension. I got the other ones that had minimal space with a external torx wrench.

I'm also trying to replace the shift rod selector shaft seal which is usually a bitch, but even more so with the x5s extended tail housing.

That might be it RB. Mine would only do it if I really gunned it in first and not in any other situation. I'm glad I got a new shaft just in case (well now I need to wait for the correct one). I'm not confident in the old one.

I also replaced the tcase mount and filled the voids with polyurethane. I'm hoping it helps shifter feel. The stock one was old and a little saturated from the leaking seal.

I've had the standing start ratchet noise for a few months now. Need to get a new chain and tear into it. DS outer CV boot torn too.

Get on it. I have a feeling that it aids in striping the driveshaft.

Great to know Josh - Btw I've read that there are actually 2 different (similar) Tcases for the pre-facelifts, the NV125 and the LWX500 - does it say on the outside of the case which one you have? Would be helpful when I tackle this to be sure I'm getting the right parts - the driveshafts are all the same but I'm sure the internals of the case might be slightly different.

I feel the same way. Been driving it easy.

The TC case has a model tag RB. readily visible from below.

Guys. what makes you think its a chain and not a drive shaft issue when you hear the "ratcheting" clicking sounds from under vehicle when you switch from Park to Drive or Drive to Reverse or any combo of that nature?

The driveshaft spline will get worse REALLY fast (vehicle will be un-driveable in a few days), the tc chain ratchet will remain constant for months.

There is no warning on the drive shaft. Splines don't slip, they simply fail.

2002 X5 3.0 291,000 miles
2014 428i 12,800 miles
2004 325i sold at 123,600 miles (currently on eBay)
2001 325i sold at 66,000 miles

The TC seals were the one item the dealer added when they installed the used case for my drive shaft repair. I guess it paid off since I haven't had any leaks in 155,000 miles since then.

2002 X5 3.0 291,000 miles
2014 428i 12,800 miles
2004 325i sold at 123,600 miles
2001 325i sold at 66,000 miles

Yeah its on the back half, right above the drain plug. Mine is the NV125. Im not sure exactly what uses the other one.

Sorry to bring up an old thread but I thought I would update on the issue/solution. It turned out to be the transfer case chain. I bought the replacement chain from cobra transmission for $93 shipped I believe. I also ordered a set of external spline sockets on amazon for $15 to get the bolts off the transfer case. Took me about 8 hours to get the whole job done with the help of my 13 yo brother. Hardest part was the exhaust bolts on the header which got rounded off and needed a $20 set of stripped nut sockets from harbor freight. The whole procedure was relatively straight-forward. I used this thread as a guide: http://www.xoutpost.com/bmw-sav-foru...-pictures.html

Thanks for all of the input and help!! :thumbup: