Here is A tip I just figured out.. maybe some of you already know this...I used a oil can with a finger pump to squirt the fluid in.. works great!!!!! instead of using the bottle itself.

 

Used this one for years. autozone could have taken a better picture of it

http://www.autozone.com/autozone/acc...ier=139278_0_0_

 

For my front diff I snaked a plastic tube from the fill port up into the engine bay and attached a small funnel to it. Pour in the fluid while upright! You lose a little lube if you're not careful, but well worth it on a Dakota where there is zero room to work on the front diff. For the rear I used a similar version but w/ a shorter hose and I did have to fill from under the bed while laying there.

 

I use this.
Lincoln oil suction gun.

 

I tried different sizes hoses I had but the ones I did were too small or to big. the other thing I did by accident on my wifes car. was in trying to drain my tranny I opened the wrong nut. I opened the crank case nut.. instead of taking off the splash guard and there was the tranny drain nut.. so this is what brought me to trying to fill the tranny case??? it was way up there at an awkward position. my truck I noticed the bottle wouldn't totally empty. Plus the truck had little higher clearance.