Early 99 F250 7.3L 4wd automatic. 2 weeks ago it stopped shifting from 2nd into drive. Turned the truck off for a bit and I checked trannyfluid and it was ok. Turning the truck off did not fix the problem. So I turned it off again and I disconnected both batteries for a few miutes to reset the PCM and that fixed the problem. Today one of the ranch hands called and said it was not shifting out of first so I told them about disconnecting the batteries. A few hours later they called me and said that fixed it and they had put 5 quuarts of fluid in it but on the way back from town the over drive light started flashing and it stopped shifting into drive again. They put into 1st and drove it 5 miles back to the ranch. Im think they might have over filled the tranny since I dont think it has been leaking fluid. Im going out to the ranch Tuesday to check it but told them not to drive it anymore until I get there.

SInce reseting the PCM has fixed it once for me 2 weeks ago and also fixed it today for awhile I am wondering if the PCM is going out. Last fall the PCM stopped sending the signal to warm the glow plugs when the truck is turned on so I disconnected that wire from the PCM and put in a switch in the cab to turn on the glow plugs manually which has worked well. Any ideas appreciated about my current tranny problem.

 

The first thing to do is check what codes are stored, anything else is just guessing.

 

Are we talking about shifter not going in D..?

 

When the PCM detects a problem that doesn't allow the trans to shift to a certain gear it will set a code, flash the OD OFF light, and not shift to the gear with a problem. When you disconnect the batteries you clear all of this. That's why it shifts again once the batteries are connected again.

If you don't read the codes it is going to cost a lot of money to fix this. The codes may show an easy and cheap fix.