[2003Xlt7.3]

I've been building a flatbed for my truck. Forgot to disconnect the ground last time I was Welding on my bed. Drove into town last night and it's driving funny. Seems like it won't shift into 4th Gear. All other gears shift fine and overdrive does seem to function. Truck has 97,000 original miles. Happened randomly. NO check engine light or anything.. Any ideas? Is it possible I ruined something electrical on the transmission when I was welding? Truck is 2003 F250 XLT 4x4 7.3

 

[jgj329]

Can you upshift it manually?

 

[2003Xlt7.3]

Not into 4th. Everything else is working fine. OD engages and disengages. Just will not shift. I can shift to second and third without issue. It's really getting annoying. I can drive on the city roads just fine but I can't drive the truck on the highway. I have tried disconnecting my battery for 30 minutes and letting things reset. I'm really not sure what it could be..

 

[Mark Kovalsky]

If it won't shift into fourth gear it WILL set codes. We need those codes to diagnose this. Forscan is a great way to do it, or you could pay an independent shop or a Ford dealer to read the codes. The places that read codes free CANNOT read these codes.

 

[2003Xlt7.3]

If it won't shift into fourth gear it WILL set codes. We need those codes to diagnose this. Forscan is a great way to do it, or you could pay an independent shop or a Ford dealer to read the codes. The places that read codes free CANNOT read these codes.

Thank you for your response Mark. Your saying there WILL be codes stored in the computer even though there is no light on dash/ CEL? I have an appointment with a mechanic Monday morning but I was really hoping to save some money.. my friend has a nice scanner that plugs in but I'm not sure on model. I will for sure post an update either way because this is seriously annoying And maybe will save someone else some headache. Definitely not cool to be in 3rd gear on highway. Makes my truck feel like a real turd when I can't go above 60mph At 2500rpm. Thanks again for your time and response.

 

[Mark Kovalsky]

You can read codes yourself. Download Forscan free at www.forscan.org. Their page also tells how to select an adapter to plug into the OBDII port. I bought mine from Amazon for less than $30.

 

[2003Xlt7.3]

The shop I dropped off the truck at couldn't figure it out. Told me I need a new transmission.. not sure I believe it since he couldn't say what was wrong.. My truck is not throwing any codes or check engine lights. Fourth gear did not disappear while I was driving. I wasn't beating on my truck and It seems unlikely with 97000 original miles I have a mechanical failure. I really don't want to drop 3k in a new auto tranny. I was planning to do a zf6 manual swap after I got more miles out of it. Ill order the adaptor for forscan to plug in... im still confused though, if there is no CEL on dash will it still be throwing a code for the transmission?

 

[2003Xlt7.3]

OK everybody! Good news! Yeah! Took it to a real auto mechanic not some loser who wanted to charge me for a new transmission. I kid you not it was the 3rd break light bulb was out causing no torq converter lock up. Make sure your 3rd brake lights are not burnt out before you buy a new transmission lol Who would have thought that a Ford engineer would wire the transmission to the brake light circuit? So thankful for good mechanics right now. Gold in this town

 

[Jose Gee]

If it won't shift into fourth gear it WILL set codes. We need those codes to diagnose this. Forscan is a great way to do it, or you could pay an independent shop or a Ford dealer to read the codes. The places that read codes free CANNOT read these codes.

Hey I’ve seen your post I havw the same problem changed out the transmission rebuilt and put it new solenoids, changed out the turbo and the injectors and no solution I get on the highway but won’t go over 60 without it forcing at high rpm’s so if the 3 break light circuit is burnt I have to change the break light or the light circuit?

 

[Mark Kovalsky]

If your brake light isn't working the torque converter may not lock. That will cause higher than normal RPMs.

I can't tell you if your brake light or the circuit is bad. I'm having a hard time seeing your truck from here.