Gear oil bottle, plastic cap fell in diff, help please.

[shawn00540i]

This is my first post and it's pretty sad to say the least. The attack of the 7yr stupid happened today to me. I have a lot of experience working on cars, I am kicking myself pretty hard over this so no flaming please... Replaced the fuel filter today on my 2000 540i, which I purchased about a month ago, and after no hitches I thought while I have it jacked up I'll change the diff fluid. I was checking with the new bottle to see if I needed a hose to fill it with and the cone shaped plastic cap came off and fell in the fill hole. I tried flushing it out with a quart of fluid, I put the hose of my shop vac up to the drain hole and partially restricted the fill hole to try to get enough velocity to suck it out. I taped a piece of gas line inside the shop vac hose & fished it around trying to pick it up. I fished around with a piece of wire bent in a hook on the end trying to drag it over to the drain hole. Nothing worked, I was not able to get the cap in a position where I could feel or see it so I need some help.

I did some searching on here and it looks like it might be possible to remove the driveshaft flange and the diff mounting bolts and scoot it forward a few inches to remove the cover. I don't have the manual for the car so some info on the simplest procedure anyone knows to replace a cover gasket that would allow me to get the cover open enough to get this out would be greatly appreciated. Thanks in advance, sorry for the long post.

[NNY528I]

As bizarre as this sounds it may be fine to just leave it in there. The old school method of changing diff fluid before they thought to include filler plugs was to fill a plastic bag with the correct amount of fluid and then set it in the diff and install the cover. The plastic was not an issue as it would get chewed up by the gears almost immediately its not hard enough to damage the gears and there is enough lash in the gears that it will not damage them or lock them up. You might try simply driving the car for a few miles and then drain the fluid, if you see bits of plastic then repeat till no more plastic, otherwise, try drain and refill cycles until it shows up at the drain.

[cal45fan]

Is it possible to open the diff?

[cal45fan]

Is it possible to open the diff?

[newton22]

Yes, and if the diff takes a crap in the future, M5 diff time.

[newton22]

Yes, and if the diff takes a crap in the future, M5 diff time.

[rf900rkw]

It may have hung in/on the carrier. Try putting the trans in neutral and turning both rear wheels backwards evenly one quarter turn. A little compress air, maybe. If all fails, go with NNY528i; grind it up good and call the diff teflon fortified.

[shawn00540i]

Thanks for the replies.

[Lord DRIFT]

I think it will be fine.