F150 Ecoboost Forum banner
1 - 8 of 8 Posts

· Registered
Joined
·
3 Posts
Discussion Starter · #1 ·
I have been searching the internet, Facebook, and TSB's for a resolution to my problem for months. If it has been solved and I missed it, I am sorry.

I have a 2020 F150 XLT, 3.5 eco boost with a 10-speed FX4. In May 2021, the valve body went out while getting on the highway and commuting home from work (no trailer). I ended up stuck in 5th gear, spraying transmission fluid, but I could limp it off the highway. The dealership replaced the valve body, and everything seemed fine.

Now towing trailers I have towed before, the mileage I am getting is entirely different. My father-in-law has the same truck, and we have tested behind his and mine, and I'm noticing a 4+ mpg difference only in tow haul mode. On my last trip, it holds gears considerably longer, even on long flat sections, rarely shifting above 8. If I drop into manual mode, I can shift and get better mileage without lugging.

The truck has been back to the dealer a few different times. They can not replicate the issue because they are not towing. I offered to bring the trailer or take the tech out, and was declined. Routes, trailer, load, etc. are all the same. Has anyone encountered this, or heard of anyone having this issue?
 

· Moderstrator
Joined
·
3,079 Posts
Are you calculating MPG or using the truck dash MPG? If using the truck's dash MPG, these may differ from truck to truck.
Others more knowledgeable will reply soon, but you may also benefit for a reset of the adaptive tables.
 

· Premium Member
17 Lariat SCLB Max Tow 4x4
Joined
·
1,211 Posts
I have been searching the internet, Facebook, and TSB's for a resolution to my problem for months. If it has been solved and I missed it, I am sorry.
No worries, this forum is very understanding and we are here to help!

I would absolutely start with a KAM reset or module reset. Trans shifts good in other modes? (Normal or Sport) I would have a look at the trans connector and make sure it’s making good contact no damage or loose pins.
Does the trans run hotter then before?
Or are temps running normal?
Torque converter locking up like it was before?
Trans or converter could possibly could have been damaged from the fluid loss. Tough to say. I would talk to a CSR and explain your issue.
 

· Moderstrator
Joined
·
3,079 Posts
This is a related thread that may help:
 

· Registered
Joined
·
3 Posts
Discussion Starter · #5 ·
Are you calculating MPG or using the truck dash MPG? If using the truck's dash MPG, these may differ from truck to truck.
Others more knowledgeable will reply soon, but you may also benefit for a reset of the adaptive tables.
Have done truck dash and hand calculated. The tables have been reset a few times. Almost wondered if there was a tune update that was applied by Ford when they worked on the truck.
 

· Registered
Joined
·
3 Posts
Discussion Starter · #6 ·
No worries, this forum is very understanding and we are here to help!

I would absolutely start with a KAM reset or module reset. Trans shifts good in other modes? (Normal or Sport) I would have a look at the trans connector and make sure it’s making good contact no damage or loose pins.
Does the trans run hotter then before?
Or are temps running normal?
Torque converter locking up like it was before?
Trans or converter could possibly could have been damaged from the fluid loss. Tough to say. I would talk to a CSR and explain your issue.
All in all the truck still shifts the same. Daily driving is still exactly the same as before. On the truck, I am pushing 70k mileage, and 10-12k of that is towing. Have a few different trailers that get towed. The one that really jumped out was a 700 lb aluminum single axle uility trailer. Typically I was getting 16mpg on highway with a single motorcycle, now I am lucky if its 8.5 mpg.
 

· Premium Member
17 Lariat SCLB Max Tow 4x4
Joined
·
1,211 Posts
Do you have a laptop or a Tablet or even a smartphone? If you download Forscan, you can monitor a ton of different things and hopefully maybe push you in the direction of something that could be causing your issue. You could have a sensor out of whack or something that just acts up when your towing…

Need a good adapter and you can monitor a ton of different things with it.
 

· Registered
Joined
·
2,992 Posts
I'd start looking for a different dealer.
 
1 - 8 of 8 Posts
Top