Save Your Super Duty Transmission With This Handy Mod

By -

Electronic Shift on the Fly Super Duty trucks have one minor transmission fault. Thankfully, it’s an easy fix.

For the most part, Super Duty pickups have quite the reputation for reliability. Especially when equipped with the excellent 7.3-liter Powerstroke diesel. But owners of these trucks have found one minor fault over the years, and it’s somewhat of a glitch. Whether you’ve got a manual or automatic transmission, the reverse gear is geared way too high. Which not only makes backing a trailer (or just backing up in general) a more difficult task. Not to mention one that can build up excessive heat in your Super Duty tranny.

FTE member cleatus12r provides an excellent description of the problem in this thread.

“The electronic shift on the fly (ESOF) uses a vacuum solenoid to route vacuum to the auto hubs on the front axle. These trucks, whether equipped with a manual or automatic transmission, suffer from a reverse gear that is geared much too high. This causes excess heat in an automatic transmission when backing a trailer. Or, a backup speed that’s too fast without excessive “feathering” or riding of the clutch pedal when using a manual transmission. By using low range in the transfer case when backing (or moving heavy loads for short distances in ANY direction), the effective gear ratio is multiplied by 2.73. This allows much lower speeds to be attained without adding stress to the transmission or clutch.” 

Super Duty

“Unfortunately for those with ESOF, the vacuum hubs, when operating correctly, will be commanded to ‘lock’ when the transfer case is in the 4-Low position. Also, in extreme cases when used on hard surfaces it will break drivetrain parts due to binding when turning. 

Also keep in mind that it doesn’t matter if you have a manual or automatic transmission. Or a manual shift (NP271) or electronic shift (NP273) transfer case, as any of these combinations can be equipped with ESOF. It simply depends on what options were selected when the pickup was ordered from Ford.”

Fixing the problem, thankfully, is rather easy. And for that, we can thank another FTE member – Sous. The OP actually went to the trouble of making a video documenting how he fixed the issue on his own Super Duty. And unlike most Internet how-to videos, it’s extremely well-made and easy to follow. And it all came about from his desire to make his Super Duty easier to navigate with a large trailer.

“This modification is for trucks with working ESOF and will allow for you to use low gear in forward or reverse in 2WD. This is very useful for ZF6 trucks, but will greatly benefit an automatic truck as well.

We all know that reverse is entirely too fast in these trucks. This is the main reason why I did the video. When using 2WD low in reverse, I can back my 5th wheel trailer up at a slow walk speed with tons of power and control.”

Super Duty

And by the sounds of things, he was very pleased with the way it all turned out.

“The switch came from a shop called Rocker Switch Pros out of Charleston, SC. I had the switch in my hand 48 hours after placing the order and I am impressed. As you can probably see in the video, the engagement of the switch is very confident and solid. There are many, many options for the switch in regards to lighting and momentary and what not. And even more options for labeling. I Googled “custom automotive switch” and found these guys. I was very impressed with their selection and customization. 

Thanks again for the advice. I am glad everyone seems to like it. I was very happy with how everything turned out. Now when I go to back up the 5th wheel next time, I just have to flip a switch instead of unplugging the OEM connector.”

And this is just one of many examples of our resourceful members taking the initiative to make their trucks better. And then, best of all, sharing the results with everyone else. So whether you’re searching for tips or if you have some to share, the FTE forums is the place to do it!

Brett Foote is a longtime contributor to Internet Brands’ Auto sites, including Chevrolet Forum, Rennlist, and Ford Truck Enthusiasts, among other sites.

Comments ()