I have a 1992 F150 Flareside 302 with an E4OD tranny
I had the tranny rebuilt in my truck about a year and a half ago but recently it has been having some problems. when i start my truck and put it in drive it first barely idles forward then if i go to give it some gas it revs up a little bit and slowly accelerates to like 15-20 mph. i can drop it into reverse and 1st and 2nd gear on the column **** and it has power and no issues. this last time this happened i heard a couple loud thunks under the truck, they sounded like they might have come from the drivers side under carriage. i looked and saw nothing under the truck. eventually the truck gets back in gear and it will operate just fine and it only does it when i start her up and it always corrects itself after about 2-3 minutes of driving.
this last time it happened it sounded as if the truck might not have been firing on all cylinders or miss firing as well
Tranny fluid level is fine, the fluid height on the dipstick is just a little above the full marker.
i just did a complete engine overhaul and i need to find this problem before serious damage is done.

so if any one has any idea as to what could be wrong please let me know