Hello all, I've just joined the forum today. I have a problem with my 1997 F350 diesel dually 2wd crew cab. The odometer will go blank and the speedometer will jump to the high peg, at the same time the automatic transmission will jump into freewheel mode, as if it put itself into neutral. The old boy I bought it from told just slap the top of the dashboard and it comes back to life. I had a guy pull the instrument cluster and reseat the plugs (I know I should have done it, but he was doing the back brakes and axle seals because I didn't feel like pulling the axles). The only code that ever showed up was internal PCM fault. And that was after the truck didn't shift when it should have and shifted HARD when it did finally shift. It hasn't done that since, but the problem with the transmission cutting out combined with the speedometer/odometer fail is a recurring problem. The fact that hitting the top of the dash seems to be what clears it up indicates a failing connection under the dash or in the instrument cluster, and not a PCM problem. Have any of you guys had a similar problem, or have any ideas? I keep thinking I should send the instrument cluster off for a rebuild, but I don't want to do that if it doesn't help. Incidentally, I bought this rig with around 200K miles for $2500, and added a bed and fenders a few other things. So knowing the truck had the problem didn't stop me from buying it, but I'd like to be able to use it. Have the trans disconnect with a load going downhill is an interesting proposition. Sorry about the long post, and thanks in advance for any help anyone here can give me.
Edited to add: I forgot to mention that it will also drop the speedometer to the low peg while the odometer blanks out, in which case the transmission stays in first gear if the truck is stopped or moving slowly. The red "brake" light on the dash also comes on at random times. That caused me to think maybe the sped controller, but that's been replaced.

 

Welcome to FTE!
Check the pins on the connectors and make sure none of them backed out.

 

Thanks for the reply, Z. Yeah, that's my next step. Really like this truck but if I can't resolve this problem I can't take it with me to Idaho when I move.