OK, try to follow me here, it’s a little extensive. FYI, I have a 2004 FX4 that stay’s in 2WD while this is happening, I have the 4.10 rear end, and a Superchips tuner. This all happens between about 55-65 MPH.

I’ll be cruising and the trucks RPM’s is at about 1600. When I decide to give it some gas, just a very little bit, the truck is supposed to stay in 4th and accelerate just slightly while staying in 4th and maintaining the RPM’s around 1600-1700. Now, this only happens half of the time. The other half of the time while cruising at the mentioned speeds the truck will be at 1600 RPM’s and when I hit the gas, just slightly, it goes to 3rd. It actually felt like 4th gear was slipping until I got the feeling for the problem this afternoon. Now, I know it sounds like I hit the gas hard enough to down shift it but I didn’t. Here is the strange part. Lets say for instance that I am at 60 MPH and I hit the gas lightly and it is doing this thing when it goes to 3rd. If I maintain this very slight pressure on the accelerator it will shift after about 100ft shift to 4th. Then with a slight press of the pedal it will now act like it is supposed to staying in 4th and accelerating normal.

Now I know this might have been a little confusing so let me try and sum everything up. The truck is down shifting when it’s not supposed to into 3rd. The only way for me to get it out of third and act properly is to maintain steady pressure on the accelerator for a little while for it to shift and stay into 4th, then under light pressure I can accelerate in 4th without this thing downshifting into 3rd.

One more thing, I noticed this after I passed a big rig in my truck on a two way street. I floored it to get around him and all this started happening. On another note, when passing this truck with it floored, the shift from 2nd to 3rd was very stiff and hard due to the Superchips tuner. Much harder that I notice on a normal day to day driving or other shifts into 3rd at WOT. So right now I am thinking there is something wrong with the trans due to the tuner. So what do you guys think?

 

Me thinks your crazy. Go back to the stock tune and watch the tranny's behavior. You also failed to mention how long ago you installed the tune. Shifting can be a little funny for the first few tankfuls while the PCM figures out your habits. There is a bunch of variable in this... like I said, if you really think you have a problem (I don't) then go back to the stock tune, let 3 or 4 tanks of gas go through and she how she feels. My money is on everything is just fine....

 

Had the tunner for about 4500 miles. This is the first time I've had this problem. I also went and drove my dads truck and his doesn't do this....

 

And is pops truck tuned? Apple to oranges.. .

 

OK, I'll try it....

 

This is strait from ford on how the tranny learns how to shift. So going threw a few tanks of gas is useless (unless you like going on drives for no reason)

 

Asinatra, so is your post a to-do article on how to get the trany to learn how you drive?

BTW, here is a slightly another/better example of what is going on....

Under normal operation on my truck, lets say I'm going 60mph at 1600 RPM. If I'm in 4th gear, when I give it the slightest amount of pressure on the pedal, the truck should accelerate while remaining in 4th gear and the RPM's should begin a slow climb as I accelerate. Lets say 1700 RPM at 63mph and so on. My problem is that I am cruising at 60mph and when I hit the gas, sometimes it does what I just explained and sometimes the RPM's jump up to about 2300 RPM. When this happens, I take my foot off the gas and the RPM's go back down to 1600. Push pedal again and the RPM's jump back up to 2300. Now, in order for me to get this to stop, I gently push on the accelerator for a few moments (2300 RPM) and then I feel the shift into 4th (now 1600 RPM) and I can accelerate in this gear. Now keep in mind, this whole time my speed is practically unchanged so dont make the assumption that my speed has increased causing a normal shift into 4th.