Sorry for the long post, but just trying to capture everything so hopefully someone can help me troubleshoot.

2002 F350 Superduty Crew; 7.3 Diesel; Auto Tranny; Superchips Programmer; 8" lift; 38" PJ's; 4.56 gears; 102K with regular maintenence. Mostly freeway miles; I've taken it pretty easy on the truck since I bought new in 02. No hauling, no wheeling, just a street queen (that's why I have a Jeep!). Programmer has been installed since 15K with no problems, and I have never experienced a problem after doing a trans service. Pulled codes PO 732 and PO 783 when I first ran into the problem; "Gear 2 incorrect ratio" and "2-3 shift malfunction" respectively.

Running out of time for a weekend trip and had about 25K (almost all freeway)on the trans fluid, so I took it to a shop that did a fluid exchange, no pan drop. Usually do the service myself, but no time. Shifted a little harder than normal, but I thought no big deal as it was new fluid and I take off for my trip. Second day the O/D OFF light starts flashing and it will not shift from 2 to 3rd on the street. I pulled the codes (see above) and let it sit for about 3 hours, started it up, O/D light not flashing, so I decide to drive home (about 150 miles = 5 mi to freeway, 140 mi fwy, 5 mi home) and I don't experience another problem until I get off the freeway, then I get the same O/D light flashing and no shift 2 to 3rd.

I park it on an incline, drop the pan & filter and get almost 3 gallons of fluid out. Didn't want to run it through the normal torque converter drain in case something may break worse while I'm doing the service. No metal or debris in the fluid or on the magnet, solenoid packs & valve body still tight and in place. Put in a new filter and new Mercon (not V) and uninstall the programmer in case the shift points are screwed up somehow.

Drive it again around town, no problems. Get on the freeway and it goes through normal shifting all the way through to OD. Get off the freeway, come to a stop, take off again and same problem, no shift 2 to 3rd.

Still have not reinstalled the programming and have not driven it more than around town (about 15 miles total) since.

Any ideas? I don't trust any of the shops I have dealt with in Nor Cal (I live in Vacaville). It's more than just their desire to replace rather than diagnose; it seems whenever I take a rig somewhere it comes back with more problems.

I can't help you with a shop recomendation as I live in AZ, but I know most shops don't want to dig into these trannys when they can stab in a rebuilt in much less time and pass the warranty off onto the reman company.

I have had numerous tranny problems and my best advice is if you plan on keeping the truck, replace the tranny with a better unit from BTS. I know it costs more, but the tranny is the fuse in these trucks, and you have a long life left in that truck.

Ask around on thedieselstop.com youll probably have better luck diagnosing it.

sticky valve in valve body, failing solenoid in the solenoid pack.

quite a few possibilities that could be the problem expect the answer on the the diesel boards to simply be that you need a new transmission.

Yeah, I posted the same note up on thedielselstop.com (thanks s.monkey) and have gotten a range of responses from "get a new trans" to "sticking shift valve."

I tend to do all my research for my jeep here, so figured I would start with the same path on the truck; very informed people who seem to have done it all and don't have a problem sharing.

Think I will drop the valve body & start going through the valves this weekend, but since it's an auto, that's about my limit.

Thanks for the responses so far, and anyone else is welcome to chime in if they have an idea.