Well, I've had my '97 F350 for a few years now, its been a great truck but I've recently run into a new set of problems, transmission related and I'm hoping someone out their can offer a little input. Its, a 351w truck, automatic with 197k original miles as far as I can tell. The truck was running great until a recent trip to Vermont (I live in Rhode Island). About 100 miles or so into the trip, the truck started having trouble with hills in overdrive, as soon as I started climbing, the whole truck would start shaking and I would constantly loose speed, no matter how much I pressed the gas, and the rpms remained relatively constant. I just attributed this to the transmission overheating, pulled over, let it cool down a bit and then carried on my way, but it continued to happen, but now in both overdrive and 3rd gear. I got to my destination, the truck sat for 2 days, then I drove it back, taking it easy and had no problems. When I got back, I changed the transmission fluid and filter because I figured after 197k, it was pretty well roasted. I had hoped this would eliminate the problem but alas, reality is cruel. Anyway, now the truck will go through 1-3 gears just fine, shift into od fine and do good on a flat surface, but as soon as I hit any incline, the truck just feels gutless, no matter how much gas I give it, I can barely maintain speed, never-mind accelerating, but the shaking did go away. The pedal will eventually go to the floor and it'll kickdown into 3rd to finish out a big hill. I figured the clutch packs might be worn and the thing is just slipping but the lack of any rpm change seems a bit odd (off course the rpm changes when it kicks down into third). I'm wondering if anyone has had any similar experiences with their vehicle or of the problem could possibly be electrical. Also, on a side note, I've been having an issue with pinging, the truck was timed correctly, then advanced one or two degrees and even with 93 octane, I'll still get a small amount of pinging when I really get into it. I tried replacing the fuel pressure regulator, thinking it was running too rich, now I'm wondering of the fuel systems on these trucks have a return line, that I haven't found that was capped by the previous owner. Sorry for such a long post, just trying to be as detailed as possible.
Thanks in advance for any help/advice
-Alex

 

sounds more like engine trouble than trans trouble to me.

 

It very well could be, minus the slight ping, it seems to run great like around town in 1st-3rd gear, could it just be the added load of being in overdrive is too much.

 

I agree it sounds engine related. When is the last time the fuel filter was changed? When was the last ignition tune up? I would also add some fuel injector cleaner to the gas tank. You may have to consider backing the timing off if the pinging continues.

 

Usually this is caused by misfire. Plugs, wires, cap, rotor, or even the coil.

 

There is a fuel return line (one to each tank if you have dual tanks). I'm not sure what would happen if you were to cap them, but I don't think it would be good. At the very least the fuel pressure would no longer be regulated, and would run too high, especially at lower rpm / throttle settings. But my guess is that you'd have much bigger problems than you do if the return lines were capped, so I doubt it's that.

 

Does it still have a catalytic converter?

 

I'm no expert on this transmission matter but I would use the brake pedal to disengage the TC clutch to determine if that will help with acceleration. The brake light circuit when activated will signal the TC to unlock. You should feel the engine rev up until the TC locks up again after you release the brake pedal.

 

It is do for a fuel filter change, as far as I know, its the original one and the truck still does have a catalytic converter. It also does burn a little oil, probably should've mentioned that.
As for a misfire, is there any way to tell if it is misfiring without replacing all the ignition components and finding tdc on the compression stroke of cylinder one and re-timing from there?

 

No need to worry about finding the tdc, if it is running smooth. You just need to turn the distributor a little bit counterclockwise to retard the timing, but best to have a timing light so you exactly where you're at.

I would change the fuel filter and then do the ignition tune up per post #5. Also consider the cat converter as mentioned.

 

plugged up cat is a good guess for sure with her bogging out in high gear.

 

Little update, new fuel filter today and a bottle of injector cleaner. Plugs and wires are on their way along with an injector rebuild kit. We'll see how that goes and then I'll be looking at that catalytic converter.

 

I would also add some fuel injector cleaner to the gas tank.