I was driving up a small grade dead empty and the truck went to downshift from overdrive and shifted to second. next time I stopped I noticed it started in 2nd gear. I believe my ABS light flashed on the highway during the highway speed second gear downshift. 1998 f350 automatic. plenty of fluid, doesnt smell burnt. maybe 6000 miles on the trans. 114,000 on the truck.
So as of now the truck has functional 2nd,overdrive, and reverse. gears hold strong , no slipping.
I did a search but couldnt find anything. Im a little unsure of what to search for?
any help would be appreciated.

 

Since you've not had a reply, might I suggest starting in the correct forum. This is the 87-96 section.

 

Why would this be the wrong section?

My guess would be that the VSS has failed. Start by checking the ABS system for codes. Is the speedometer still operating normally?

 

A bad shift solenoid can do that. Does the OD OFF light flash? Codes will be stored, too.
I can't imagine how a failed VSS could cause this.

 

You stated it was a 98, perhaps you meant 88?

 

The ABS light flashed so that was why my guess is the speed sensor failing. Does it not need a speed input?

 

The OP's profile shows they have a 1997 F350.

 

It needs a speed input, but no speed input or erratic speed input won't cause no first or third gears. It can make all the shifts late, but it can't prevent only two gears.

 

The speedometer still works and I believe my ABS light was the only one that flashed. I will see if I can pull codes. I believe the truck has a VSS in the in the rear diff and in the transfer case? I could ohm check the sensors right? Also not that it really matters but the F350 was still a 9th gen truck in 1998.1999 was the change to the super duty platform. 1998 F250's were a tenth gen truck that looked like the f150 for one year? weird.

 

There was no 98' F350. Either a 97 OBS or a 99' SD. The 10th gen LD F250 was a 97/98' model, the HD F250 retained OBS styling into 97'. I'll agree it's weird.

 

Thanks, probably doesn't help with your troubleshooting, but I didn't know they carried that style in to 98.

 

Thanks for the clarification. I was assuming it was might have been in a "limp-in" mode.

 

Limp in mode is mostly an internet myth.

 

Not a myth with Chrysler transmissions. You would only have reverse and second gear. It was enough to get you to the shop without burning up the transmission. Obviously if 2nd gear broke then you were screwed. Don't know enough about Ford transmissions to realize they did not have a similar mode.

 

Ford determines which gears work and which ones do not and only use the ones that work. Chrysler did it very differently.