'97 F-150 Trans question

I've got a 97 F-150 XLT:
170,000 miles, well maintained with all services done, and Never been off road.
4.6L.
4WD.
W engine.
R470D Transmission.
I recently serviced the trans with a new filter and flushed it out completely, including cooler and torque converter with Mercon V in an attempt to solve a lockup problem. Now I have the lockup problem AND it does the "Rumble Strip" vibration at~~ 45mph/1500 rpm. I have to "kick it" a little to get it to unlock. This trock has had a set of plugs, wires, pcv valve, egr valve and MAF sensor on it to try to solve this problem.
The filler cap on this truck indicates Mercon, not Mercon V. Did I create a problem by doing this?

I've got a 97 F-150 XLT:
170,000 miles, well maintained with all services done, and Never been off road.
4.6L.
4WD.
W engine.
R470D Transmission.
I recently serviced the trans with a new filter and flushed it out completely, including cooler and torque converter with Mercon V in an attempt to solve a lockup problem. Now I have the lockup problem AND it does the "Rumble Strip" vibration at~~ 45mph/1500 rpm. I have to "kick it" a little to get it to unlock. This trock has had a set of plugs, wires, pcv valve, egr valve and MAF sensor on it to try to solve this problem.
The filler cap on this truck indicates Mercon, not Mercon V. Did I create a problem by doing this?you didnt create a problem,try a bottle of ford friction modifier.this should help the torque converter shutter you are having. it takes a few miles to soak in.

You did WELL. The shudder will gradually improve over the next few hundred miles, and should be gone by the time you have 500 miles or so on the new ATF.

Thanks for the response.
However the new fluid already has ~~3000 miles on it, and the shudder problem just started in the last 500 or so miles. After I replaced the MAF (cleaning it did nothing) and the pcv valve, which was definitly bad.
Does Mercon V already have the friction modifiers?
How much, approximately does a new torque converter cost (Part only) I can install it myself. Also, is there an aftermarket unit that is better from a performance or economy standpoint?
thanks.