mattjoines

i have a 99 f150 lariat 5.4/4r70w. it’s always done a strange thing where 1-2 shift is pretty hard ( more than likely broke accumulator spring) and when driving 30 to 50 while barely on the gas it will pull third gear up to about 1800 rpm then rev up to 2500-3000 (almost like a slip) then catch overdrive. when floored or on it pretty good it will go all the to 5k and not “slip” only happens under light acceleration. what do y’all think the issue is? fluid looks great not burnt or anything. i’ve put 27k on it since i got it and it’s been doing that since day one. i’m not convinced it’s a slip.

jprevat

iTrader: (1)

I'm assuming you have already dropped the pan and and refilled with the appropriate fluid and changed the filter right? How is the level when checked warm?
Under ligh acceleration when it slips does it bang into gear or go smoothly?

DarrinT04

If you have never changed the fluid and filter I reccomend you do that