new '05 E-350 trans sticks in 3rd

i just bought a '05 E-350 with the . doesnt even have a tank thru it. driving down the freeway at 55 to work today along a flat stretch of road it just downshifted out of OD into 3rd. i slowed down to about 30 and it went back to normal (back into overdrive). it was fine the rest of the day--50-60 miles or so.

next morning, 3 miles down the road *clunk* it dropped into 3rd again going maybe 10-20 mph. i pulled over and decided to go home and get my old truck. but, 15-20 miles down the road it started shifting right again so i turned around and continued to work.

6 hrs later when i went to go home it was fine for 10 miles or so. but, in rush hour traffic, from a dead stop it started in 3rd again. about 2 miles down the road it just cleared up again.

that brings me to today. its sitting in my driveway wondering what will happen tomorrow.

needless to say i'm concerned. is anyone familiar with any tranny issues with this make/model? i have a buddy who says that '04-early '05 there were issues with the trans. i cant find anything online tho. and, service departments are closed for the weekend.

i'd like to have some info in hand when i call monday morning.

any help appreciated. thanks.

You have a 4R100 trans, and *most likely* the TFT (Trans Fluid Temp) is getting too high, or the EEC *thinks* it is, so it is unlocking the Torque Converter (not really downshifting).

There are other things that can cause this, like a brake switch that sticks, or a feed-back in the brake light circuit that tells (falsely) the EEC that the brakes are being applied. The EEC will UNlock the T/C ANYTIME the brake pedal is depressed.

It is also possible that there is a problem with the wires to the EEC from the TCS (Transmission Control Switch) on the end of the shifter, telling it to unlock OD unintended.

All these are easily repaired at your local (decent) FMC dealership.

Still under warranty? Let the dealer fix it for free!