excuse my lack of terminology as i am not a mechanic

i have a 99 range rover 4.6hse

just got out from under my rover and saw where the transmission leak is coming from

when the transmission end it meets a large unit that controls the axles (i think its what they are called) what is the unit that is about the size of a basket ball that the transmission connects to

its leaking from the seals on that unit

also the owner manual says only service visits can check the transmission levels - is there a way to sidestep that and do it myself + add transmission fluid - to hold me over until i can afford the repair

ok all i had to do was call dad - transfer case...answer my first question

what about the checking transmission fluid and adding more can it be done without having to take it in for service?

If the transfer box is leaking you top that up, NOT the gearbox. They are seperate and do not share an oil supply. Level/filler plug is on N/S just in front of handbrake drum. Change the output shaft oil seal.