Just driving my van ('97 E-350, 2wd, E4OD, Triton) for the first time on the highway here and the trans seems to slip a bit and jump a bit under acceleration. I haven't checked the fluid yet or really done any service as we just got it and only drive it across town once a week to church.

More troubling however and my question is that at about 40-45 mph a heavy shudder develops under even moderate acceleration. If I let off and coast down to 35-40 and lightly accelerate it's still there (and only under acceleration) and it is such that you wouldn't really think of accelerating through it for fear large metal chunks would explode beneath you. But once you drop below 35mph (even at 34mph) you may then accelerate as if nothing happened up to about 40-45. It doesn't shudder under heavy acceleration at slower speeds, so I suspect it's isolated to 3rd gear (perhaps 4th)?

I think the fact that it doesn't happen in lower gears at equal rpms rules out the driveline. It's 2wd so no T/C. The rear is a Dana FF 60 3.55.

Is my transmission going? Oh how I love manual transmissions!

After searching around a bit I'm guessing the (apparently) dreaded Torque Converter Shudder. Going to change the fluid and filter and see what may...

I guess I should also mention that I received it with the OD ****/button/diagnostic light broken off. Anyone know the default condition when the OD switch is gone?

 

Any other possible causes? COPS? EGR (it was throwing an 401 & 402 code but hasn't come back since being cleared)?

 

None of that sounds like a transmission problem. I think it is a spark plug, or even more likely an ignition coil.

The default is overdrive enabled.

 

Thanks! Good to know the default until I get it fixed.

What COPs do you recommend? Motorcraft #DG 508/Ford #3W7Z12029AA

I should also add that the van has been completely gutless since I got it. I figured it was just an old van thing, but after reading around here a bit I am positive it is related to either a bad cop or two, fuel pressure regulator (read a thread that caused similar symptoms only more temporary), plugged cats, egr, or some such. Probably just bad cops?