Here is a brief description of my most recent ambulance purchases: I have a 1994 E-350 ambulance w/7.3 IDI (along with the others). I bought it, the '92 ambulance, and a suposidly good spare engine and E4OD tranny for $850 in 2007. The ambulances, wich both run, have sat at the ambulace company since 2004. The '94 has only 30k on the rebuilt engine and tranny, while the '92 has 162k on the origional engine. I have finnaly been able to get the '94 ready to temporarily replace my ailing truck. I have changed all of the fluids, including the transmission fluid and filter. I drove the '94 on the highway for the first time the other day. (Keep in mind it has only been on the road for about a week since '04.) Everything was fine when I parked it, but when I started it back up again the O/D light was flashing steadily and the shifting was harsher than normal (indicating the tranny has increased presure). I do not know if this has anything to do with my problem, but my speedometer has always bounced all over the place. In an effort to fix that problem, I replaced the speed sensor in the rear end. It seemed to help the problem but not fix it (it now starts bouncing at 40 mph instead of 15). I have also replaced the TPS in an effort to fix my tranny problem with no results. Where do I go from here? Does the bouncing speedometer have something to do with my problem? Although not really related to my problem, I also replaced the stock tranny cooler and upgraded to 5/16" lines.