EllaAirplane

So, I've got a 2005 F-150 with the 4.6, and about 141,000 miles. Replaced the spark plugs and intake manifold gasket at the dealership around 6 months ago, as well as one of the coil pacs ( I can't remember which one). New problem has just popped up and I'm fearing the worst.
When taking off from a stop during hard acceleration the truck doesn't want to go into 2nd gear. Once I'm above 20ish MPH it seems to slip into 3rd and there are no issues. If I can manage to coax it along gently, it usually slips right on through the gears like butter. I've got no CEL and it seems to do fine at higher speeds/gears. I'm fearing the transmission is going out, but would appreciate any other ideas. I've got no RPM gauge so really can't tell you what that's doing. I've done a little research but can't find anyone with the exact issue mine's having, and I plan to take it to a shop to have it checked out later this week but would like to be more prepared than I currently am.
Thanks!

techrep

iTrader: (1)

EllaAirplane

Fluid level was less than a quart low has since been topped off. I’ve owned the truck almost 4 years and haven’t had the transmission serviced before.

techrep

iTrader: (1)