1993 F-350 7.3 Diesel. Hunting for gears and hard shifting?
 

Bought a 1993 F-350 with 7.3 diesel engine a couple months ago. It was in great condition with only 140K for $4000, so it seemed like a great deal. But the day I picked up, the dealer had it detailed, after which he claims it started hard shifting into first and gear hunting. Seemed, like it might be a moisture issue and thought it would dry itself out after sometime. But it has not.

Here are the symptoms: If I try to take off slowly it won't shift into second until I hit high RPMs and then it slams into second. But if I push harder on the pedal when I take off, it will go right into second, but then it will gear hunt, shifting gears 3 to 6 times before it settles down. It only has problems on take off. Once it is up to speed it works fine. Also, there is a little light (the word OFF) that starts flashing on the gear shifter next to the the word overdrive. It does not start flashing until after the hard shift or hunting thing starts.

I have never owned a diesel with an automatic trans before, so I took to a transmission shop to have it looked at. It is a shop that has been around for decades and has a really good rep. The owner called me and told me that he could not do anything with the truck, because as he said, "Ford never released the codes for this particular model". He said he drove it around and felt all the symptoms I described. He said the fluid looked good and he did not feel that the problem was mechanical. He said the little flashing "OFF" light indicated that the problem was sensor related, but without the ability to read the error codes, he had no way to know where to start.

So, I figured I would try to replace the sensors myself. Since the truck was new to me, I went down to get a repair manual. Guess what? There is no repair manual for my year model. A friend of mine knows a retired Ford mechanic with 30 years experience. He talked to him about the problem and asked if he had a shop manual for the truck. To the mechanic's utter surprise, he could not find a shop manual for my model of truck.

So here I am. I have a truck that is almost 20 years old and nobody, even the experts, seem not to know anything about it. I am desperate here. I don't know what do next. I am hoping that someone here on this forum might have the same truck, with the same symptoms and can tell me how to fix it.

Any help or advice is appreciated.