im getting ready to change the front and rear diff. fluid in my 96 cherokee. my buddy has some thing he rigged up that you put in the filler hole of the diff. and you turn it on and it sucks out all the diff fluid. we plan to use this. i have never seen or heard of anything like this before. just wanted to see if you guys have done anything like this. any pointers? i have never changed diff. fluid before. thanks guys

 

There are companies out there that make hand pump vacuums specifically for things like that. I've never done it myself though.

 

They work. Lube shops use them. You just stick the tube in the diff and remove all the fluid. The only time i would use a vacuum system is if the diff cover seal is still dry. If you see any leak or even some sweating i would just pop the cover off and reseal it. I use a gasket maker called the "right stuff" instead of the paper gasket at the parts stores.