Transmission works cold but not hot
I have a 2000 F-150 XLT 5.4 2wd, Transmission has no problems when cold, but once i drive for a while and it warms up, reverse stops working and it slips when shifting gears. Once warmed up and shifted into reverse, it takes up to 3000rpm to make it slam into reverse and then it shudders the entire time. It will not down shift when passing slower cars either, only a loud clunk and it stays in the same gear. It hesitates between shifting also. It seems like if something was broken inside it would work at all. Right? a quart of Lucas Trans additive helpled the sitiuation for about a month, then slowly stated again. Whats the deal?