So my 1-2 shift has been almost non-existenet since I bought the truck but it's getting worse. I've checked the kickdown, filter, fluid etc...all the recomended stuff on the board.

Today I decided to put it in D-2 and see what happened. Well it shifted perfectly from 1-2 at 2800-3000 rpms what does this mean?

In D I have to get up to 4000+ rpms and then let up off the pedal for it to go into 2nd.

I'm thinking if it shifts good in d-2 then there must be a specific component in the valve body that needs a cleaning or replacement??? not the cable, 1-2 valve or governor if it works in D-2, what else could it be?