.. without knowing code its a hit or miss you can try the alternator.. we ran across the same thing on a older body style auto we rebuilt the trans in .. kept setting 2 different codes i cant remember what they where but i scanned it and drove it we even pulled a trailer with it.. they where false alternator was doing same thing to it..

I would try it for sure! Not sure what code he saw, but even if it was an input shaft/output shaft mis-compare (indicating slip) this could all be caused by screwy speed sensor signals. If you or your tech have access to a scan tool that will allow you to read sensor data live pull up the following parameters:

RPM
TSS
OSS
VSS
Selected Gear

If you are getting interference, one or all of these values will be all over the place when the truck is sitting still and you change the rpm in Park or Neutral. When I unplugged the alternator, they immediately settled down and everything was normal. I have an old oscilloscope, and sure enough when I scoped the alternator, it was 100% the culprit.

It sounds crazy, but it sure beats a trans rebuild! (mine only had about 10k miles on it, so I was VERY relieved it was not a major issue.)

Good luck.

[QUOTE=Rwbrew3;3885847]that is way too much to rebuild a trand,,2k tops....try this,,pull the VSS out of the top of the rear diff,clean it and put it back in,,they usually get covered with metal shaving's from the gears chaffing..this will also throw off the VSS and make it shift wierd..when the newer electronic ford trans start to go you will have to petal shift it and it will slam into the next gear..

New swamp diesel idm which supposed gives it 30 hp more. It goes in tomorrow with the inner fender off to access the wiring.

I will look at the alternator in the am but it reads good on the amp gauge . The chip is a superchip so I was able to eliminate it and program it back to stock.

I think we have 2 different threads wrapped up into one

I don't think the alternator is your issue...

plug it in on the block heater cord,let it sit over nite,if it starts but with a long crank time then its the idm..

Thanks for the info!! Im going to try it this weekend!!

[QUOTE=mrfixxall;3885910]Thanks, I'm deffinatley going to try all mentioned, $3300 to rebuild is crazy for sure!!

Sorry for the high jacking!!

If the IDM doesn't fix it I had a simliar problem and it turned out to be the IPR harness (located on the back of the HPOP). The harness wasn't making good connection - consequently it wasn't telling the PCM that the HPOP had generated 500lbs of pressure required to fire the injectors. You might want to look there.

There is also a kind of poorly designed bronze nut on the back of the IPR that sometimes works its way loose and creates a similiar situation.

Good Luck - I just sold my 7.3 on Monday, but miss it already.

EDIT - I got lots of funny codes when this was happening including IDM, PCM, etc.....