How do I check th fluid level in my transmission 1999 Trooper?

if its an automatic trans u will see 2 plugs in your big trans pan. with the engine warm and running u take the one out thats at the top or the deeper of the 2 if u catch my meaning, if fluid comes out u are full,if not get a suction gun and fill through the same hole until fluid drains out. the other plug is your transmision drain plug

You are correct Isuzus....

1.Go underneath the suv, passenger side, just past the passenger wheel.
You''ll see a black pan. Use a flashlight.

2. You''ll see two plugs, one is pointing down towards the ground. The other one is at angle on top.

The one pointing up is where you fill up with new transmission fluid.

Follow Isuzus instruction above.