Was changing the oil in the rear diff today and since it was raining here I did not pull out of the garage and let the spare down to get to the fill plug. I thought I would put the quart container of gear oil up to the fill plug to do a trial fit to see if could get the oil in. Anyway when I put the spout up to the fill plug I slipped and the little blue plastic cap went into the diff. I took the drain plug back off and ran a quart of oil through, hoping to flush the cap to the bottom and out. No luck. Don't know of anything else to do but run it and let the gears chew it up and drain and fill again in a few miles. Any thoughts on whether this could cause any damage or not? Really would hate to take apart just for this, but also don't want to tear it up either. Wish the diff had an inspection plate on the rear like some I have had. Thanks for any thoughts and yeah I know how stupid this was.

 

That sucks. What if you tried blowing some compressed air in the fill plug? If that doesn't work. I'd fill it with the cheapest stuff I could find and drain it out in a few hundred miles. The plastic cap won't hurt anything, I don't think.

 

unfortunately you have an ARB locker, the plastic could cause it not to engage, otherwise it'll just chew it up and come out in your next few oil changes. In the most part it won't hurt your rear end....

 

Hardened metal vs. cheap soft plastic. The plastic won't know what hit it. Forget about it, drive it a while and if you still remember change the diff oil. Next time, don't slip...

 

Yep...don't worry about it. Just look for it in your next change. In pieces, of course.

NOTE: An interesting tid-bit --> In the past, doing rear-end fluid changes in vehicles without a drain plug, i.e. old GM 10 and 12-bolts, I had a trick. I would get one of those heavy-duty ziploc bags, fill it with diff oil, and stick it behind the diff cover, and bolt the cover on. WIth the rear end jacked up, put it in gear, let it idle, and the gears popped the bag inside the diff Big help on old axles without easily reachable fill plugs or if your hand-pump just happens to die :-)