You must not overfill the transmission. Undo a line to let a couple quarts out and replenish with fresh fluid. Now if the fluid is really burnt, a fluid change will do no good(overhaul needed). Take a white napkin and examine the fluid off the dipstick. If there is excessive clutch material, an overhaul will be inevitable.

if burnt smell DO NOT change or flush it leave it alone till it goes. find shop at ATRA.COM for more help

Just fill it all the way to the top of the dipstick and you should be good to go.

Maybe, it's too hard for us to know, with so little information.

what else do you need to know