Oil & Fuel John Deere 450C change transmission fluid / filter

[farrellapparel]

Hi, My 78 JD450C acts fine usually but hesitates or won't go under load if you stop and try to go again. Needs a head of steam. My t fluid looks like a latte so I was going to change it out along w/ filter. Do I drop the belly pan? Then what?
I'll take all the tips I can get.
Thanks!
John in Seattle.