Strange clicking noise under hard acceleration

[benfbuilder]

Hi all, . 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.

[upallnight]

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

[upallnight]

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.

[srmmmm]

Originally Posted by trader4

Most likely culprit is the transfer case chain, slipping on the sprockets.
The chain gets stretched over time. It can be inspected by removing
the drain plug, at least on the transfer case on 2002 3.0 vintage.
With the plug out, you can see the chain and use a screwdriver to
see if there is play in it or not. It can be replaced for ~$100 in parts.

It's possible it's the driveshaft splines too, but from what I've heard,
seems that failure mode is usually complete, ie once it starts the
splines strip so bad that the car won't go. The chain thing can go on
for a long time. That's what it was here, several load click/pops
when starting out from a stop. If you applied very little acceleration,
it could be avoided.

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

[Joshdub]

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

[Clockwork]

Originally Posted by benfbuilder

Hi all, . 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 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.

[benfbuilder]

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!

[Joshdub]

Originally Posted by trader4

Correct me if I'm wrong, but if you install a longer front driveshaft,
I assume you can no longer remove the DS without removing the
transfer case? The standard length uses that extra empty space to
be able to slide the DS back so you can get the DS out without
removing the TC, doesn't it?

If that's the case, should be prepared for that. Would be a real
bummer to bolt the TC back in place, then find out you can't
get the longer DS in.

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.









And the difference between pre facelift and post facelift.

[Ricky Bobby]

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)

[Joshdub]

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.