well that didn't work too well... (diff oil change)
 

There I go and pull the covers off the differentals and promptly dropped a pile of sand in the gears. I tried brushing off the covers and blowing it out with compressed air first to no avail.

I wiped the rear gears off the best I could then refilled (not much dropped and stuck on the rear)

On the front the sand dropped in the spider gears. I wised up and hosed the area down with wd40 before sealing it up and refilling.

So, for future reference, how does one deal with the sand and dirt falling in the gears when changing the oil?

I sure am a big fan of drain plugs now.....

I guess wire brushing around the covers before pulling them.

go to a car washand wash it first

I agree,

I was very sure to make sure everything was very clean prior to opening the diff up. I can't imagine your pain trying to clean it out when stuff got in there.

1- wash it first..

2- keep a can of brake / electric motor handy for a rinse prior to replacing the cover..it dries relatively fast or can be blown out to make it dry even faster..

I'll have a couple sleepless nights wondering if I got it all. I may just turn around and do a change again next week but by then the damage may be done....

On a sort of related topic, I wonder if it would hurt anything if a person were to drill and tap through the bottom of the cast housing to install a 1/8 NPT allen head plug?

I was thinking the first time you have the covers off could be the last time, without springing for expensive aftermarket covers...

Have done on some occasions with success. Get a plug with a magnet is good also. If you want to take cover off, glue a magnet to the pan.

I may think about doing it...

I wouldn't think the small hole could effect the structural strength of the case, considering the rear dif has a considerably larger hole for the speed sensor.

On the other hand, it's nice to lay eyeballs on the gears if you are changing oil anyway...

I would want to make sure the inside where the plug is going will not interfere with anything

Yeah, I think if I were to do it, I'd cut the threads so the plug tightens flush with the exterior of the case so it wouldn't get smashed by rocks or anything on the outside, and wouldn't protrude on the inside...

The more I think about it, though, with that reuseable seal there's no cost to pulling the cover or lost time waiting for RTV to set up... I'm thinking I'd be better off by just not being lazy and just take the cover off each time. It really wouldn't hurt anything to look at the contact pattern every once in a while, anyway.

I'd change that fluid again. A few times. But thats just me. As stated ^^^, brake cleaner will help get alot out, the current fluid will help get most of the dirt to the bottom, and clean the differential before taking it apart.

I have done it for lots of Rockcrawlers.
The downside is I use a 1/8 NPT and it drains VERY slowly. I just tell people to find something else to do when it drains. I do not like the larger holes.
I order up some 1/8 allen head NPT plugs from McMasterCarr