I left my house and everything was fine with my truck. It was shifting normally, and had all its power. I got about 5 minutes away from my house, and when I hit 4th gear (4 speed auto) I was able to go for about 30-45 seconds before it lost almost all its power and I was forced to drive at 40-50 mph (It doesn't idle differently or anything, and it still has it's boost pressure) . I haven't changed the fuel filter in the year and a half that I've had it due to not putting many miles on it. I have diesel 911 in it as well. I can't get it over about 2500 rpms. My tranny does slip, but I don't see how it could have finally went. It still shifts until the higher gears when they take more rpms. I am going to replace the fuel filter, but I was just curious to see if anyone has had this happen to them before, or could give some insight on what it could be. Thanks.