Automatic trunk lid not functioning

[josiahg52]

Haven't driven the X5d lately. It's just been parked in my garage on a battery tender. Thought I'd take it out for a quick drive earlier this week and found the auto power rear upper trunk lid (option S316A) will not close. It seems jammed.

I've read about different failure modes. I don't think it's an issue with the lower tailgate as I've seen that "failure" to close and that's not how it's behaving at all. It attempts to close but seems to torque a bit. Watching it closely, it looks like the left spindle drive is seized or electrically compromised. Contributing to this is that I can't even force it closed but then again, I'm not sure I could do that before, that it's even possible.

Not done much troubleshooting. Electrically it seems to want to close. I have not tried pulling Fuse 99 and/or 121 which seem to control the tailgate interlock. So far I've just observed the attempts.

Any ideas it should I just pony up the $500 for a new left side spindle drive?

[andrewwynn]

If the thing runs from simple ±12v like most similar motors I would take it apart and run it with a drill battery or similar up and down and clean and lube the gears before replacing.

You can force closed usually suggesting the gears are gummed up.

[josiahg52]

Yeah, I thought I remembered closing and opening it manually. Convinces me one or both spindle drives are locked up. I know there's a motor, a preloaded spring, and obviously a jack screw inside the drives. Not sure what it runs on or how serviceable it might be.

[andrewwynn]

Search YouTube. If it can be serviced it'll be there.

In the meantime, remove the broken one and see if you can open/close the hatch.

Either pure manual or hit the button and do the job of the left side lest you overload the good side.

[ard]

Check this one out...
https://www.youtube.com/watch?v=OyGMsnfNFq0


Good info in the comments section too.


My recollection is that grit and dirt leads to the plastic spindle drive nut eventually cracking... but its been a while since I paid attention to this.


Ive always thought Id replace mine with gas struts when it failed. 10 yrs and 170 it hasnt failed. Plus who knows if there IS a gas strut interchange!

[josiahg52]

Well, some news. I think I found the problem and it's definitely the left drive. I mangled the s*** out of the mounts. The videos I found say "just pull this clip here" or "pop it with a screwdriver" but don't show s***. Well, mine wasn't moving. After tearing up that metal wire clip, I ended up pounding out two roll pins on the door side mount and then was able to knock out the mounting block. Then I tore the s*** out of the body side mount and twisted the f*** out of it until it popped off. Probably screwed myself when I go to replace it. I tried shutting the trunk and it closed and latched. Sort of by gravity and maybe by power. Clearly, the right drive is under some stress in this configuration. I cut the wires for the left drive giving me the option to splice in the new one instead of removing every damn panel from the tailgate interior to reach the plugs.

Took if for a drive and man, is it a smooth runner. Only thing is that there is a rhythmic, rotational sound. At first, I thought it was tire flat spots as it hasn't moved in months but it didn't quite feel like that. Thought maybe brake disc surface deposits but a few gentle bedding stops didn't seem to really change it and I don't feel anything in the pedal. Last thing I thought of was wheel bearings. Could be but in the past I found that braking or accelerating or turning one way or another changes the tone of the sound or eliminates it as the weight is moved around. I'm still hoping it's a brake disc issue since when coming to full stop, the brakes feel "grabby" just as it fully stops and there is some visible spotting on the outside rotor surfaces. It's not a vibration, just a sound.

[andrewwynn]

Use a vibration isolation app to determine the exact frequency of the wub wub wub. Math can help determine the source 7.3 ft is the exact circumference of the wheel 88 ft per sec at 60 mph for example means 88/7.3=12.055 Hz at 60 mph is absolutely in the final drive elements; past the differential.

If it's triple it's in the inner CV joint if it's double it's in the outer joint. If it's 3.9x or 4.1x it's usually the GIUBO (JOO-boh) or CSB.

If it changes from tuning it is almost always the wheel bearing. The good news is so they are under $50 OEM. (the bad news is you need a special tool to r&r).

The best way to confirm it's a bearing is to put on a spare tire on each corner. If you have 255 or wider tires, changing to 235 will swap which bearing races have the weight of the car while going straight and the sound will disappear. (also can make the sound appear).

Wheel bearings don't wear out they get damaged from impact. Their is a bmw tsb about the issue; they insist you replace any wheel bearing impacted in an accident least you have the customer come back in six months because the bearing sounds like a UFO landing.

Also, I've found that if remotely suspect it's a wheel bearing it absolutely Is a wheel bearing.

https://apps.apple.com/us/app/vibrat...o/id1089589547 if you have iPhone this is the app I use. It's solved numerous what the hell is vibrating my car situations. I'm especially happy with the 3:1 ratio = inner CV joint. I think the outer is six faces so it could be 2:1 3:1 or 6:1 but you'll likely see multiples if that joint is failed (it just chaos; like gravel in gears sound like mine when it failed; got enough sand in my outer joint that it actually locked at an angle. That was exciting at 30-40 mph!)

[josiahg52]

Took it out again this past Sunday and I didn't hear anything. I mean, it might still be there but it's really quiet and I might be hearing nothing. To be honest, it wasn't particularly loud to begin with and I couldn't ever feel it. I'll be looking to use the truck again this week so I'll continue evaluating.