Got 2 major problems with a still-new-to-me 97 F-350 diesel with a recently remanuctured Jasper E4OD automatic.

On a road trip this weekend, I let the rear tank run dry before switching, and about 200 miles later the engine suddenly lost almost all power and started running really rough. I figure I sucked up some glop from the bottom of the tank and clogged the fuel filter. Had to limp home at 20 to 40 mph. Luckily I had no load. I've got the engine question posted on the diesel forum.

The transmission chose the same time to act up. I can understand that minimal power at throttle has the computer confused and is causing problems with the shift points. For the power the engine is generating, the transmission needs to downshift a LOT sooner than with a healthy engine, but I guess the computer hasn't figured that out.

What has me really concerned is that the upshifts got much harsher. 2nd to 3rd has a noticable "kick", but 1st to 2nd is downright violent even though there's very little engine power. It feels like I just got rear-ended! Something will break if this keeps up. Normally, this rig makes a liesurely, soft upshift. I could sometimes avoid the violence if I got totally off the throttle just before the upshift occurred. If I mistimed it, POW! Don't know about 3rd to 4th shift, couldn't get to 4th gear speeds. Also, the "Overdrive Off" light is flashing. Downshifts, when they finally occur, seem normal.

Has anyone experienced similar transmission symptoms with a sick engine? Did they go away after fixing the engine problem? What has me concerned is that after correcting the engine issue, I will still have a significant transmission problem.

Thanks for any help!

 

I had a similar problem with a Chevy. Got a load of bad gas, which unknown to me had clogged my fuel filter.

The car started to run poorly and the tranny always seemed like it was slipping. It would rev up to high rpm and when it shifted it would do so harshly. I thought I was in for a rebuild. The car barely had any power, just enough to reach freeway speed, very slowly and then maintain it. There was not enough power for passing or acceleration.

When i finally figured out that the filter was clogged and replaced it, the engine started to run fine and the tranny settled down.

From an educated guess, I would say the filter had choked off the fuel to the point where the engine would run but couldn't make any power. The computer to compensate, moved the shift points to high rpm.

Replacing the filter fixed it for me. If you have done this and still have a problem, you might gunk in the lines or clogged injectors or carb. You might even have another clogged filter if there was enough gunk in the tank.
Good Luck,

Jim Henderson

 

The harsh shifts are normal when the engine is low on power.

During a shift pressure is added based on pedal position. Since you are far into the pedal you get more pressure, but the engine isn't making the torque that the transmission is expecting, so you have more pressure than you need. That makes a harsh shift.

When you get the engine fixed the transmission will almost certainly be fine.

 

Mark & Jim, thanks for the info. Gives me confidence to take the beast away from home port once the engine is running right.

Haven't had a chance to change the fuel filter yet; truck is outside, Sunday's weather was lousy and I got back from work late today. Even though the diesel filter should be easy to change, after dark isn't the time for my first filter change, since this is a "recreational" vehicle, not a daily driver. And I'm going to start carrying a spare filter or 2 in my toolkit.

 

Also, the "Overdrive Off" light is flashing.

Here is another thought and queation for Mark. Running out of fuel shouldnt make the od lamp flash. I believe some trans electrical problems (shorted epc for example) will cause some engines to misfire( run on half the cylinders). Really need to know what codes have be set for the trans concern since this all started about the same time..