I have a 2011 F250 4x4 Gasser with 5000 miles. Had my oil changed the other day, along with had em checking a strange prob with it slipping when shifting from 2nd gear to 3rd. I thought maybe t was due to extreme cold and it only happened couple times. So they also updated the pcm. So, ... now I'm really paying attention to the shifting patterns while driving. As I'm watching this on the lcd display in console truck runs into 5th gear, and once it hits about 40mph in 5th, i notice a significant drop in rpms, but no gear shift. Then it will shift eventually to 6th. My question, is this the tranny/engine going into its overdrive mode? I do not believe it does it when tow/haul is engaged. Is this normal???

 

Probably locking the torque converter.

 

Let me eloborate a lil more, say I'm at 35 mph when it gets into 5th, and say it take 2 or 3 secs to get to 40mph (and there really is no constant on timing) it will reduce rpms like 400ish rpm with no shifting. I do belive i can see (and hear) all the normal shift points, but the 5th gear @ 40 mph is a very obvious one when just causually accelerating. There is no jerk or violent jolt, just that rpm drop.


**EDIT

Oppps...I must of been typing this above when the other post when up! I'm not so mechanically inclined to know exactly what "locking the torque converter" might relate and is it a good thing or bad thing?

 

Modern automatic transmissions use a clutch in the torque convertor (abbr: TCC) to lock the two halves together once the vehicle reaches a certain speed, thus eliminating the power loss and inefficiency inherent in a fluid coupling (which is what a torque converter is).

A 400 RPM drop is about right for locking the TCC.

-blaine

 

Agreed, it must be the TC locking. This is normal and done to make the driveline more efficient. To put it in very simple terms, before it locks the engine is spinning faster than the transmission as the converter is slipping a bit. Picture driving a manual shift vehicle with the clutch in just a little bit. When the converter locks, it's like letting the clutch all the way out. Since there is now no slippage the engine and trans are now locked together spinning at the same speed. Hence the RPM drop...

 

Thanks for bringing this topic up Firewiz, my
2011 acts the same way. Thought I had a rare
7 speed trans all this time, giving me two shifts in
5th gear(grin).
Thank you Frankenbiker and Karl4Cat and projectSHO89
for the info on the converter...

Mike in PA

 

I have the same problem but it does it in 3 gear instead...its at the dealer so I'll just see what they say it is.

 

Let us know what they say Tex...

Mike in PA

 

I have the same odd shifting between 2nd and 3rd gear at times. Did the PCM update eliminate the shifting issue?

 

Well I just back from the dealer. They didn't know what was going on. We even took a new truck on the lot but it didn't drop the rpm's like my truck did. He said they would call Ford's hotline and see there are any new updates or any other complaints.

 

Despite what engineers tell us, no two transmissions ever function identically. Statistical variations in both mechanical machining and electrical components mean that every transmission is just a little different.

I'd say that it's nothing to worry about.

-blaine

 

Thanks for getting back to us Texas. Would also like
to hear what they come up with from the hotline.

Mike in PA

 

Well I got bad news. Ford had instructed them to clear the PCM and to reprogram it. In doing so they fried the computer. The truck will not start and of course the part is on national backorder. There's no telling how long I'll be out of a truck. It's been there since Monday.

 

fify

I know of plenty of transmission that shift identically.

 

Just a heads up, the torque converter in the 6R140 locks up from 3rd gear on so this may be what you're feeling when you say it's slipping from 2nd to 3rd.

real_texan - sorry to hear about the PCM!