I have a 1999 isuzu rodeo and it has a sealed transmission, and it needs to be filled, are there any diagrams or help to fill this?

I won't take credit for your answer, but this video is very good at explaining how to check the fluid, as your vehicle, like many newer vehicles there is no dipstick in the transmission or transaxles to check the fluid.

http://www.youtube.com/watch?v=JHbrkXgYysA

I believe the transmission on the Rodeo and Trooper are sealed units. no dipstick and no oil fill hole.

1999 Isuzu Troopers w/automatic transmissions do not come with a dipstick. It is a sealed transmission just like a manual transmission. The fluid must be checked by removing the fill plug. Emergency brake on, engine running,warmed up ,vehicle in neutral. When removing the fill plug ,which is on the side of transmission- at the top, fluid should slightly drip out. If fluid doesnt drip out you need to add fluid. You will need a small hand pump to fill it.

Clutch and tranny fluid does not go in the same place whatever you do don't mix them as for where to fill the clutch fluid, believe it or not some of the clutch share a resovoir with the brakes but others have a smaller resovoir right next to the break master cylinder, but that's only if you have a hydraulic clutch some where actually cable so it wouldn't take hydraulic fluid at all.. I hope this helps

what size engine?

Usually you just fill with a funnel, unless it is at an awkward position.

As far as I have found the 02 Isuzu Rodeo does not have a transmission fluid dipstick you have to in fact go under your vehicle to check, change and fill your transmission fluid. Transmission fluid level: You will have two plugs facing downward on the larger trans pan. The plug higher up on the pan is the fill/level check (stamped/recessed into the rear right corner of pan). ATF should just dribble from this plug on a hot, idling truck, in neutral on a level surface. The lower one is the drain. The one at the back of the pan in a recess is the filler. You need a hand pump or something similar to fill it to overflowing then top it off with the engine running. Make sure you shift through the gears a couple of times when topping off.

Auto Trans.and manual Rodeo has no dipstick. Fluid levels must be checked from underneath the vehicle on a lift at the shop. It can only be filled from underneath the vehicle as well.

you either have to fill it through the transmission dip stick if it is equipped with one, or you need tho crawl under the car and look at the side of the transmission and you should see a plug looking bolt which you will have to remove and fill through there till it runs out that plug hole

Transmission fluid level:
This type of vehical has a sealed transmssion and there's no way one can check the transmission fluid level. There are two plug at the bottom of the transmission the drain and the filter.
As you don't have an ATF dipstick, you will have two plugs facing downward on the larger trans pan. 
The plug higher up on the pan is the fill/level check (stamped/recessed into the rear right corner of pan). ATF should just dribble from this plug on a hot, idling truck, in neutral on a level surface. The lower one is the drain. 
The one at the back of the pan in a recess is the filler. You need a hand pump or something similar to fill it to overflowing then top it off with the engine running. Make sure you shift through the gears a couple of times when topping off. 
Good luck and hope this helps

Lee2fixit doesn't know what he talks about on 99 Rodeos.

There is no dipstick tube - there are two access holes on the side of the transmission. The bottom one is to drain it out. The top one is to fill it back up. It is full when the fluid comes up to the bottom of the top hole.

Or you can take it to a dealer or service center to have it done.