Low/high speed grinding sound
 

Hello fellow enthusiast, please bare with me, I will be including lots of details for the issue I am experiencing;

About a week ago, I noticed a fairly large puddle of oil, at the time, I thought it was engine oil, it did not have the fuel smell of used engine oil, but I had done an oil change recently so that made sense, anyway, I checked the engine oil and it was at the mark I left at when I changed the oil, weird, okay.

So fast forward to 3 days ago, my wife is on her way to work when she calls in a panic that there is this loud grinding noise, I drive there, investigate the car and notice that the front driver side axle is about 1/2 inch out of the diff... so, in the parking lot I lift the car and tried to snap it back in, that didn't work, I then pulled fuse #46 and went for a slow drive, noise was gone. I drove it back home, removed the axle, apart from diff fluid being everywhere, I did not see any issues with the axle, circlip was good, splines were good, nothing wrong with it, even the CV joints were good. I put the axle back, seated it back into the diff (really complicated when you're working in -32 degree weather), refilled the diff with 75w90 oil. Put fuse #46 back and the sound was still there. Remove fuse 46 sound is gone again.

Details about the sound, it is really loud when driving low speeds, I can feel the steering wheel shake at about 2mph. It seems to be coming from the front/mid of the car. I remove fuse 46, sound is gone, this tells me its not trans, brakes or wheel bearings, its either transfer case, front drive shaft, diff or axles(?) It sounds like straight cut gears in a race transmission mixed with metallic grinding. I have not driven the car higher than about 5-10 mph with the grinding sound because I don't want to cause more damage. When my wife was driving she was on the highway at 60mph and I could hear the sound over the phone. It is loudest at lower speeds and steering does not influence it.

Details about the car; 2006 X5 4.4l canada spec car, got the car a couple of months ago, no lights on the dash (anymore), changed a lot of engine related things, VANOS solenoid seals, oil, filter, fuel pump and filter, spark plugs, expansion tank, water pump, water transfer pipe to water pump the short rubber/metal one (this actually caused a coolant leak which I need to investigate and fix too, it's not the usual n62 transfer pipe as that was fixed by previous owners mech), thermostat, all the coolant temp sensors (they were aftermarket, temp gauge was inaccurate and causing no start issues, I used VNO).

There are no codes to speak of until I remove fuse 46, then the dash lights up with traction control, ABS warnings.
From my understanding, I have been reading tons about this, the facelift model does not suffer the same front driveshaft issue as the post-face lift model, it could still be the case? How would I troubleshoot this?
I checked both front axles, they seem to be fine, wheel bearings would not be the issue otherwise the sound would remain after pull fuse 46, it's not brakes for the same reason.
So (to me) the only culprits would be the t-case, front diff, front drive shaft and maybe the axles, maybe axles make the sound only under load(?)

How would I go about troubleshooting this quickly/easily, it's bloody cold here at the moment and I need to fix this outside in the elements.

Side note, I have no cooking clue how the front driver axle popped out the diff... I did notice that when I removed the 12 point 36mm nut, the splines were free of the wheel hub and I did not need a puller or anything to remove the axle hub side... So someone was in there recently... :banghead:

Any advice is welcome, I am fairly proficient with cars, I rebuilt an e46 ground up.

Thats a strange one for sure. Sounds like the PO may have had the same problem and had to re-seat the axle as well. Could the axle joint(s) have failed in some way that is hard to duplicate with it out?

That's probably wishful thinking, so my guess would be a failing front diff, or I wonder if it is possible for a failing tcase or front driveshaft splines to cause things to vibrate badly enough to pop the axle out of the diff.

I'd start with the easy and move to the difficult as you rule stuff out. I seem to recall your car will drive without the front driveshaft? If so maybe pull the front driveshaft first, check the splines and if they (and the Tcase splines) look good then take it for a drive in 2 WD mode. No vibration would narrow it down while vibration remaining would certainly point to maybe the axle or most likely the diff.

I'm afraid none of it's easy, especially with your temps, but the front diff in my view would be the most challenging by far. Motor has to come up a few inches and the subframe needs to come down a few inches. It also weighs a ton so getting it back in laying on your back is fun. I'm not sure there is a rebuild kit for it either, but ebay pieces aren't too expensive. Notwithstanding the cold, it sounds like you could swap the diff out in a hellish day or two if you have a way to lift the motor and enough jacks/jackstands. PM me if it comes to this as I just had mine out of my 2002 E53 4.4.

When I pull fuse #46 to get it to rwd or 2wd, the sound and vibrations are gone, to pull the front drive shaft I need to remove the t-case since its the electric t-case (xdrive) with the shorter drive shaft, I did read some information about removing the guibo then the shaft, but that was for the pre-facelift models, currently I couldn't do that until summer anyways due to -30 degree weather.
Good point on the vibration causing the axle to pop out! It entirely could have been, we have owned the car for 6 -7 months and the sound/vibration only started 3 days ago. I do believe the axle popped out before the sound started though, I dont daily drive it so I couldn't say for sure.

From what you said though, it may seem that it is the t-case, it's a good point that driving it in rwd mode and the sound stops, which it does, technically the axles are still spinning the diff and crown ring, just not the pinion and drive shaft, therefore the only non moving part would be the t-case, the front driveshaft and or diff pinion, right?

Without removing the t-case/drive shaft what would be a good way to diagnose further?

Thank you for your input!

Ok, so it sounds like you drove it in 2wd mode after you pulled the fuse. Forgive my post-facelift/non M62 ignorance...and the fact that I should have read your original post more closely! I know post face-lift T-case's are different (limited slip?) and I think the front diff is different in some respect. I'm not sure if they are different internally, but I do see reference to "cast iron" front diffs on older E53 x5s.

I'd say that whatever stops rotating/operating (in the Tcase?) when you pull that fuse is a prime candidate to look at, and the splines too.

If it does look overwhelmingly like the driveshaft splines, I'd just cut your old driveshaft at the spline weld (Tcase side) and work it out. Then get the Everbuilt lengthened front driveshaft spline kit off of Amazon. Assuming the driveshaft and tcase side splines are identical to the pre-facelift models, I can tell you that you'll be able to get significantly more splines in the tcase without pulling it.

The Tcase end is quite deep, but the OEM spline and shaft design don't allow for the shaft to sink very deep into the Tcase for removal. The Everbuilt fix can be set where you want it and will go much deeper into the transfer case to allow for installation. The new splines are longer, as is the part that fits into the driveshaft, which allows you to cut the driveshaft back a bit further, giving you additional play to install it. The dinky dust cover may sit a bit further away from the tcase, but you can trial and error it before cutting too much, or find a different dust cover solution.

I was able to get an extra roughly .5" of splines into the case without removing it, and could have done more but the fit of the splines into the shaft was very tight and I gave up trying to work it back out after overshooting a bit. I had 20 years of splines not failing on the old shaft (although they were looking a bit rough in spots, so I figured an extra .5" on the new splines would way outlast the rest of the car at this point.

This is all assuming you luck out and it is the splines on the shaft. If your AC condensate line drips on your tcase/driveshaft I'd seriously suspect the splines.

Have you looked at the right axle? I wonder if it could be out of whack somehow enough to cause the vibrations and the left axle to pop out? A long shot but maybe worth a look.

Oh interesting, I see the spline kit, that’s a good thing! Thanks for that!

As for the passenger side axle, it seems to be fine, Apart from taking a look at it, I didn’t investigate further, I will take a look once the snow stops.

Regarding the t-case, I believe that the n62 has a clutch pack instead of the planetary gears like the m62 has, it has a little motor on the side of the t-case that actuates a worm gear to engage or disengage the clutches, either turning it to awd or rwd, so by pulling the fuse you disable that motor, along with traction control and abs (which is an issue in snow, that’s why I don’t just leave it rwd) there really isn’t enough info on the t-case insides for the facelift models.

As for the post facelift, I think it’s just a mechanical ratio split using planetary gears? I’m not sure.

The thing that concerns me the most, is that the spline issue is not a common at all on the n62 facelift, where it is on m62… I hope it’s as easy as welding on a longer spline gear.

But that pretty much answers my question and what to look at first, I reckon, check the driveshaft and passenger side axle, maybe take out the driveshaft and investigate.

I’ll update the thread as soon as I can get the car in the air. Thanks! I appreciate the advice!

Just a theory, but if someone has replaced the axle and had trouble with the snap ring and grove, something could be damaged allowing the axle to pop out easily and then the transfer case gets abused trying to compensate for the torque difference. You would think there would be no warning light on the dash though, unless maybe the previous owner disabled or covered it

Low/high speed grinding sound
 

I checked the splines and canal (?) where the snap ring snaps into, it doesn’t seem worn or damaged (thankfully!!!!)

Honestly though, I had a real rough time placing the axle into the diff, to the point where I took a rubber mallet handle, rested it on the inner boot wall and hit it with a hammer 6 times to get it in there. Before doing this I of course removed the snap ring and made sure the splines line up and the slid in perfectly. Somehow, the boot is not damaged. I am thinking that the extreme cold shrunk everything so it was just tight.
Oh and, the axle was definitely changed, it’s an aftermarket unit.

I used inpa and bmw scanner, no codes in the dme, tcu or abs modules for any kind of drive train issues. I actually scanned it with inpa before buying it to make sure there was no vin mismatches or serious engine/drivetrain issues.

Having just been through axle hell and back, three times, I learned a technique on this form that seemed to help a lot. Someone posted that if you have trouble getting the clip to seat, pull it out, turn 90ish deg and try again, and again, until it pops in more easily. This worked like a champ for me. Front right wouldn't go in so I pulled it back out, turned it what I felt was 90 deg and it went in with very little force. I wish I would have read this before wrestling with the first two axles. Your milage may vary of course.

I wish I had read this before yesterday [emoji1787] damn that would have helped, I’ll probably be dealing with this soon enough, thanks for the tip! Very much appreciated.

Well, I found the culprit, I took the front drive shaft out (1” modded splines were installed by PO) the drive shaft was not the issue.

I wiggled the input flange on the front diff and it has about 1cm of movement up/down/left/right and about 5mm of play front to back. So the bearing there is shot, the grinding sound is probably the balls from the bearing tearing the innards of the diff to shreds.

I was thinking of getting just a new bearing but I doubt the inside gears are any good. So a replacement diff is needed.

Im going to be checking junkyards and partouts in the area for a replacement diff. Drive shaft is out and the diff is still making the grinding sound, so driving the car is off the table, since all the fluid leaked out there’s a risk that the other bearings seize.

I will be updating the thread as I go, I’m definitely interested in what the inside of the diff looks like.

Thanks all for the tips and strategies!

There should have been a lot of whining from the diff long before it got that bad. Rebuilding the diff is not a DIY job and the gears are likely to be noisy after even if they don't look damaged. I don't think it's all that common for the diff to go out so there should be no problem getting one from a wrecker.

There wasn’t whining, I did notice “slightly worn wheel bearing” sound coming from the front when we bought the car, I was waiting for summer to replace the wheel bearings, I guess it wasn’t the wheel bearings.

I’m assuming it’s been a cascade of issues, the flange bearing vibrating popped the axle out, which introduced the diff being drained of all fluid which made the flange bearing shatter due to overheating, and now I need a new diff. That’s what I assume happened.

We bought the x5 with the wheel bearing issue which turned out to be the diff, it wasn’t that bad sounding, it was noticeable but not imminent failure bad. So I figured that job could wait until I did everything around the engine was done. That’s before knowing it was the diff and not the wheel bearings.

Well that sucks Aidzer, but at least you know now. And as long as the driveshaft is out you can do the splines if they look suspect, and the giubo. There is also a very good thread here about the driveshaft/giubo spacer route guys take to resolve the spline issue. Since you’ll have the motor up off the mounts, I’d pop new engine mounts in too if they haven’t been done.

The Bentley manual diff replacement instructions are pretty good, except you don’t necessarily need to remove the left engine mount, if you aren’t going to replace it. The top aft bolt on the diff is the long one and won’t come out because the subframe/mount is in the way. Stupid design. The other three are much shorter and don’t have clearance issues. Regardless, you can work the diff out and then the new one back in with that long bolt in the diff, or if you get the motor high enough (several inches) you can at least get the bolt all the way out of the diff with the space made between the diff and the top of the mount. You can also loosen all 4 bolts, although some are easier to access than others. Extensions, wobble heads and universal joints will be needed in various combinations.

As far as getting the diff in and out, it’s heavy and needs to go up into its “area” head-first and towards the back of the oil plan/subframe area, then rotate 90 deg or so, then move forward so you can get two bolts started to hold it in. It’s at least 45 or 50 lbs so I got it started upwards with a floor jack, but the rest was bench pressing. All while trying not to damage the outside seal, or the inner o ring seal that is supposed to be protected by a flimsy metal sliding ring (presumably slides back to expose the o ring as you torque the diff into the oil pan). The metal ring kept on popping off as I wrestled the diff into place. No leaks though so it’s tougher than it looks I guess.

An engine hoist would be best for lifting the motor a little bit at a time, and two floor jacks on either side will allow you to drop the sub-frame easily onto jack stands. I’d shoot initially for about 2 or 3 inches down on the subframe, and about the same on the motor, but in increments. The subframe is held up by six torx head bolts and has a guide pin on the unibody to help get it back up into place easily. You may need a little trial and error as you find the right amount of space between the motor and the subframe to maneuver the diff out.

Finally, one of the guys here recommended Amsoil severe gear oil in the collapsible bag. The filler hole is a bit hard to get to, so the collapsible bag worked like a champ for me. Three bags were more than enough for the front and rear diffs. I think each bag is 1 quart, delivered to your door. The plugs can be a pain, and mine did come out finally, but I’d recommend ordering new ones. They take a giant hex head for some bizarre reason. Another tool that only has one use…thanks BMW. The good news is now I have a whole set of mostly useless giant hex head drivers.

Amazing information!! Thank you so much!

Regarding the driveshaft, I had one hell of a time getting it out because it is the 1” extended spline shaft, the job was done by PO. I actually took an angle grinder to the input flange on the diff since that’s going to get swapped out, i literally took off about 2 mm off of the diff flange and the drive shaft popped out without the transfer case needing to come off.

Good idea on the engine mounts!! I’ll definitely do that, I’m also thinking since the n62 motor has that stupid alternator bracket seal/gasket issue, while I’m in there I might as well change that.

Regarding the diff oil, I just turned the drivers side wheel and I have access to the hex fill plug, I did notice that it has a green o-ring, so I’ll see if I can get those too. I’ll also change out the rear diff and transfer case fluid while I’m there.

So the shopping list for me so far is;
Alternator gasket
Both axels (just in case)
Diff 4:10 ratio
Both sides output shaft seals
Engine mounts
75W90 gear oil (I have a transfer pump if needed)
Hex fill/drain bolts or o-rings for front and rear diffs

Would there be anything else that I need while I’m there? Thanks!!

I keep forgetting that you have an N62. The Bentley procedures are the same, but take it all with a grain of salt!

My plugs didn't have o-rings, so I ordered new plugs. I wasn't sure if I could just throw a generic crush washer on them. I read that there are different torques for o ring and non-o ring plugs, and my new ones came with o rings.

The alternator bracket is a very good idea, since that causes the N62 guys no shortage of heart ache it seems. Having the stiffener plate off, the diff out and the sub frame down a bit opens up a lot of inspection space, so in addition to the oil pipe o-rings, I'd do all your power steering crush washers, inspect all the heater hoses that you can see (assuming any are routed into the basement of the engine bay like one is on the M62 cars), and if you pull the fan and shroud to make more room to get the motor up without damaging your radiator by mistake, I'd perhaps replace any lower coolant hoses since they are cheap and can be tough to get off without the extra space.

As far as the splines go, I don't get the sense they are a problem with the N62 cars, and yours are newer anyway. So if they look good then I'd leave well enough alone. Maybe some N62 guys can weigh in. Having the diff off would certainly make installing longer splines "easier" though.

All good ideas, I got quite the shopping list now! Thank you very much!

The aftermarket extended splines were already welded onto the drive shaft.

While I was down there on my initial troubleshooting I checked for leaking coolant pipes and nothing seemed to be leaking, I do however plan to do a full power steering refresh which will be for another day. I am using someone else’s workshop so I cannot be there for too long unfortunately.

I do have a coolant leak on the passenger side by the rad, it seems to be seeping through a 3 T junction of small hoses. Not sure what part is leaking though, I’ll be replacing those hoses and the T junction once the diff is fixed. I don’t need extra room for that, thankfully.

A quick update, I got a replacement diff from a salvage yard, I got most of the parts that I need, the dealership did not have the profile gasket (P/N: 31507527999) that goes between the diff and oil pan, they only had the o-ring (P/N: 31511213527).

I also did not get motor mounts due to extremely high pricing at the dealer and also availability where I live, the motor mounts were replaced by the PO anyways so its not detrimental to the job.

I will need to wait 5 days for them to get the profile gasket in, which is a bit of a dissapointment, I was hoping to have the diff replaced this weekend. But alas, I will have to wait for next weekend. I am really looking forward to pulling the diff and cracking it open too.

Nice work! I had to shop around for motor mounts as OEM were crazy money and the better brands were out of stock at a lot of places.

I'll be interested to hear what you find inside that diff, pics please. Mine weeps the slightest bit of oil from the lower bolts holding the halves together, but I couldn't torque them at all. I did a half hearted look for gaskets and any other internals for the diff and couldn't find anything on the internet either. I guess if it ever comes to it and I need to address any heavy leaking I'll need to make a gasket.

One more note, I had a tough time pulling the breather tube out of the top of the diff. The flexible rubber bit that went into the diff was nowhere near flexible any longer and it shattered. I ended up having to make a new connecting piece out of larger vacuum tubing. A lot more wd40 and patience may have helped.

Noted! Thanks! I have tons of silicone hoses laying around so I am sure I'll find something. I replaced all the vacuum lines in the E46 and E53 with silicone so they don't perish.

I am definitely taking photos of the busted diff and I will be posting them here.

Side note; this diff is not heavier than the E46 diff or manual trans, I installed those using my chest as a jack on a crawler :P It's not fun, but doable.

To start the adventure, three nights ago, I was on the way to the shop where I’d be replacing the diff, 3 minutes away from the shop, my front wheels seized up and I landed up in a snow ditch, had to call a tow truck to get her out and drop her off at the shop. Nothing was damaged at all.

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Okay, I take it back, that diff gets really heavy when trying to manoeuvre it in there, I got the old one out, the new one was having a hard time going in the same way but I got it in, I snapped the damned subframe bolt, front one passenger side where the engine mount is, any quick fixes for that? I need to wait for summer to properly drill it out and re-tap the threads…
I was thinking of using a ratcheting strap for the time being, around the subframe and frame rail. Or Does anyone think it would be okay to drive with no support bolt right by the engine mount? (I don’t think it’s a good idea). The rest of the subframe bolts are torqued to 94ft-lbs while the car was on the ground.

I had the car running for 45 minutes and driving for about 20 minutes and all seemed to be fine, I figured that even without that subframe bolt, I want to make sure all else is good, which it was. However…

This morning I have an overheating issue, exp tank is full and there is no heat from the vents, but it is -40°F (coldest night using the x5) and I believe one of the lines got frozen or something to that effect. I will have to wait for warmer temps to make sure, what a bloody hellish nightmare.

Took the diff apart, the pinion bearing cage was the culprit. She’s done for:

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Thanks for the pics - that diff is a mess! No doubt about where the griding noise was coming from then. I had a similar problem with my diff in that it came out more easily than it went back in. I had to jack the motor and drop the subframe another inch or two to get it back up into position. I suspect gravity is the culprit, in that it helped the thing find the exact orientation and spot to drop out more easily.

Do you think there is any way you could have rebuilt it, from a parts perspective?

Aside from drilling it and using a removal tool I'm not sure what can be done about the subframe bolt. That sucks.

If I had a spare pinion gear and crown gear, with the front/rear pinion bearings, along with the centre crush ring for the pinion, yeah it could be rebuilt. I assume there are specialty tools needed though, it looks like the pinion is pressed in and there isn’t an easy way to get it out. The damage on the centre bearing housing wouldn’t influence the usability and it seems the axle gears and floating gears are fine.
It’s just a matter of getting all the parts and tools needed, I looked and cannot easily get them to me with shipping/cost etc.

Any ideas if it would be a good idea to drive the x5 without that subframe bolt? I’m assuming it’s a dreadful idea but at the moment it’s our only car :/

Thanks!!

I wouldn’t drive the car unless it’s just very slowly for a very short distance to get it home.

The only thing I can relate it to was years ago an Indy shop neglected to torque (at all as it turns out) a couple of the stiffener bolts and must have just ignored the terrible knocking noises and inability for the car to track straight during braking especially. They probably didn’t test drive it. It took 28 seconds in the car for me to figure out something was really wrong. I think that the subframe has tremendous stress on it during driving.

Thank you, I’ll have to make a plan. I’ll see what I can come up with. I kinda came to the same conclusion but wanted to see at least one other persons advice.

Just preparing for extracting that bolt, does anyone know if these subframe bolts are steel or aluminium?

It looks like aluminium but I’m assuming they are steel? But I really can’t tell. Wondering if it would be easier to weld a nut to it and extract it that way. (I’d rather not drill it out if it’s steel)

Never mind that question, I can check with a magnet [emoji2359] haha it’s been a very long 3 days.

It’s steel. Damn… that’s going to be fun…

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Get a left-hand drill and some easy-outs... and wear safety glasses!

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https://www.amazon.com/REMOVER-BROKE...BBD/ref=sr_1_5

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Gotta ask, why left hand drill bits?

Because drilling with right-hand drills just drives the broken bold in deeper... Using a left-hand drill helps the broken bolt un-thread... you might as well give yourself every advantage you can! :thumbup:

Low/high speed grinding sound
 

That’s a good point. Would it hurt if the bolt fell into the frame rail though? Because tightening the bolt it was loose but loosing the bolt it had a lot of resistance. Maybe if I use right hand bit it’ll just drive the bolt into the frame and drop in there?

I’m not sure if there are any drains or anything in the frame rail, that’s why I ask. Don’t need drains getting plugged and rusting the frame rail…

I will probably get left hand drill bits to be honest, but it’s an idea.

This should be the last update on this thread, last night I finally assembled the car with all 6 subframe bolts.

Extracting the broken bolt was a steaming piles of a nightmare, it took roughly 8 - 12 hours of drilling, hammering and drilling again, a mate of mine and I were taking turns and he got the final blow to get the bolt out. Only broke one drill bit which was a surprise… but it finally gave up. I chased the threads on all 6 nuts in the frame to make sure. I put a tap through the mangled threads and a bolt fit in perfectly. For anyone wanting the front subframe bolt specs: M12x1.5mmx66mm galvanised steel. Apparently it’s tty but I have no actually written documentation to state that.

I used a normal hex head as a temp replacement, I’ve ordered 6 new subframe bolts just to be sure that this does not happen again.

Thanks to all for your input and knowledge, it’s very much appreciated.

Ouch...sounds super painful. Glad it is done.

They are definitely TTY bolts. According to my Bentley manual stage one is 56 nm (41 ft-lbs) and stage two is +90 degrees. There are spirited threads on this and other boards about if you need to replace these bolts every time you drop the stiffener plate (they aren't cheap). I haven't replaced them yet but want to now that they have been on and off probably 4 or 5 times over the life of my car.

Stiffener plate bolts are tty, I am referring to the subframe bolts, one of which I had to drill out. Some folks say they are tty but some say they aren’t.

However torque procedure is the same as stiffener plate bolts, if I recall, the subframe bolts are 100nm + 90° so that tells me that they are tty.
Regarding the stiffener plate bolts, yeah, I reckon mine are due to be changed too, but I’m sure that can wait for another day haha.

You can replace these bolts cheaply by buying the correct grade or better bolts from Belmetrics on line. I got six grade 10 bolts, nuts and washers for the price of one BMW bolt. They're not zinc plated, but they are cadmium plated.