Seems like a stupid question, but what is the best way to get the fluid INTO the transmission? There isn't much clearance on my 4x4. Is there some sort of pump I should purchase?

 

Try some plastic tubing and a funnel, from above

 

For the manual, use a small siphon plastic hand pump that you can get at auto parts stores for about $6-$10.

 

If your trying to fill an auto tranny, pull it's dip stick & use it's tube as the fill point, with a tranny funnel, that has a neck sized to fit the dip sticks tubing & a screen to stop any undesireable from going in.

Or in a pinch, if you have a manual tranny & are pumpng gear lube, I suppse you could also use a funnel from above, with a length of plastic tubing, but it would likely be slower & in the end messier.

Or with the hand pump & some plastic tubing mentioned above, which it would seem to me, to be, faster, more controlable & less likey to make a mess.

Those hand pumps can also be had at places like Marinas, Bass Pro Shops, Cabellas, as they are designed to be used to pump the more viscous gear lube, to fill lower units on outboard engines.

But they will also pump the lower viscosity tranny fluid, so it would work just fine for that too.

Harbor Freight, Nothern Tool, Tractor Supply & most Farm Supply & Hardware stores should have them also.

I got a nice siphon/transfer, combination pump, with tubing included, to pump my low viscosity tranny fluid, from Harbor Freight on sale for $4!!!!

I wouldn't try to use it to pump the more viscous gear lube though. IMO the bottle fitting, lower unit type hand pump, would likely be the most all around versatile to have, but buy one for each type of fluid to be pumped,so you don't cross contaminate yyour fluids.

Just some more options that come to mind.

Let us know what your doing & how it goes.