When the temperature is below 40 degrees and my truck is cold I have an unusual transmission problem that the dealer says they can't help me with. My first 0.4 miles to a stop sign at the bottom of a long hill are all driven without ever stepping on the gas. Backing out of the garage and turning around are all done without any gas. Then I have a LONG downhill, at which the truck roles at 25-30mph and upshifts by itself into third gear. After stopping, it often stays stuck in third gear on a cold day. Since I have to pull out into a high speed road stepping hard on the gas will force a downshift with a VERY loud and nasty clunk. Is there a known fix to that problem? After warming up, the transmission is fine.

Of course, the solution is to keep it in first gear on the downhill and that's fine for me, but my wife won't remember to do it or even how to do it. I'm worried that the clunk might be damaging something.

And the dealer can't reproduce it because it requires the downhill roll to upshift when cold. The truck is a 2016 F-150 Platinum FX-4 with the 3.5 Ecoboost.

 

There may be some TSBs... I'm sure someone will come along to help with that. Transmissions can get weird when things are cold.

In the absence of a better solution, I would consider keeping the transmission in M and manually shift it for the short period.

 

When you're going down the hill the transmission won't down shift if you start braking sooner. It should downshift as you slow unless you're stopping very quickly. Sounds like something is amiss.

How many miles are on the truck? Has this problem just started?

 

Since your truck is close to 3 years old, has it done this since new?

 

I also live in a hilly area, and even in sport mode (which I use 100% of the time), the tranny DOES upshift by itself down the hill without touching the throttle. Therefore, I start in manual right off the bat. In my case, if no cars are behind (most of the time), I stay in first gear, so I don't have to wear my brakes out prematurely over time . After that, there's a second dowhill, not as steep, but still keep the tranny in manual to also avoid prolongued brake usage. I shift to 2nd, then 3rd, and back to 2nd near the traffic light. At the traffic light, I put it in D (and block 10th and 9th. I only use 9th at higher speeds. And 10th never). I have to say the cold 1-2 shift can be brutal, regardless of M or D, when very mildly accelerating... so I accelerate a little bit to avoid that, then ease the throttle. Even when hot it's an issue, but less brutal. The good news is just a bit of acceleration mitigates that, so not a huge deal. But yeah, this tranny cannot be considered refined by any definition. Ha ha. I can try going downhill in D next time OP, to see what mine does. If I were you, or your wife, just move the lever to M, select 1, then back to D at the stop, and problem solved. Hopefully the manual mode allows you to do that. Please report on that. Finally, if your truck started doing that all of a sudden, that's not good news. Or is it the first time you're noticing that? Let us know. Good luck.

 

I always stop very slowly at the end of this downhill, because I have to pull up very close to the highway at the bottom to see beyond the curves in both directions and pull out safely.

I bought the truck as a brand new leftover in March, 2017 and it has about 30,000 miles on it. It had the problem last winter also, but the problem never appears in warmer weather.

 

I bought the truck as a brand new leftover in March, 2017 and it has about 30,000 miles on it. I do shift it to manual and 1 when it's cold to avoid the problem. My resistance do doing this stems from the VERY old habit of not revving a cold engine above 3,000RPM. I'm not sure how important this still is with all the ceramics in the engines now. This is my second winter with this truck, and it had the same problem last winter.

I don't have many cold 1-2 shifts with my foot on the gas but when you say that shift is brutal, that's the way I would describe the downshift from 3 to 1 when I step on the gas at the bottom of the hill if I have rolled down in D. But I was on a winter trip to New England last year with the truck and never noticed a cold shifting problem, although just about all of those shifts were on level ground.

 

I didn't see your comment until today when I posted about a problem trying to do a map update.. My truck still has the weird behavior of not downshifting from 3rd after stopping if I never stepped on the gas going down the hill with a cold engine and transmission, and of course I drive it in manual downhill most of the time, starting in 1 and then going to 2 to avoid revving the cold engine. The problem is only significant on the very few occasions when my wife drives the truck, because she is extremely non-technical and has a hard time dealing with instructions like the ones needed here.