I have had the "trans shudder" problem with my 97 E250 (5.4) since I bought it used. The dealer replaced the torque converter and it still had the problem (going up hill before it would down shift it would shudder). Even though I had a 30 day warranty, being self employed I couldn't afford to be without the van again so I have been just either nailing the gas to force it to down shift or keeping the OD off.
I finally fixed it myself. About a week ago I had some free time (a rare occasion) so I got a couple bottles of fuel injector cleaner filled the van up with 92 octane (I normally run 87) then I reset the computer. NO MORE SHUDDER! Next fill-up I put 87 octane in it and the shudder was back so after about half the tank was used I filled it with 92 again and now I only use mid grade gas with no shudder.
Now the only problem is what needs to be replaced? knock sensor? My van should run on 87 octane without any problems.

 

I had the same problem with my 89 5.0 engine. It would go away with high octane. Then I replaced the spark plugs and wires and went back to running regular with no more problems.

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2000 Harley/Davidson F-150
Lund Bug Deflector
Ventshades
Century "Cargo Cover"
K&N FIPK Gen II
Superchip!!!
89 F-150 Lariat 4X4 for the "dirty work"!

 

I will change the wires and plugs soon, thanks for the tip.

Darin

 

Mine was solved with a change of trans. fluid, filter, and the service mgr said they added "friction modifier" (whatever that is). Haven't had a problem since, knock on wood.


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'96 F-150 302
Hedman Hedders, Catco Cat., Gibson Super Truck, K&N F.I.P.K.