Tranmission problem with a DPS6

[mark1022]

I drive a 2012 ford fiesta with 72k miles. The car has trouble shifting into 3rd and 5th gear and downshifting into 3rd gear. I just had the TCM replaced since it checked out bad and it has been reprogrammed and the clutch was tested and checked out good as well and I still have the 3rd and 5th gear change problem. If I take off really slow and if I let off the gas as soon as I hear the tcm clunking as it is trying to shift into 3rd and 5th I can usually get the car to shift into those gears without causing a transmission fault but it will almost always go into fault mode when coming to a stop and it downshifts into 3rd gear. Again you can hear the tcm working to try to get the transmission to shift into 3rd gear. Dealership has no idea what could be causing this. Has anyone ever heard of this? Could one of my speed sensors be going out and it is just not throwing a code yet? I thought maybe the stop that is in the case it self to stop the gears that the tcm turns may have broken off but I am not getting either one of the codes or the check engine light that is associated with that problem. When the transmission does go into fault mode one of two things happen. Most of the time I lose 1st and 3rd gear and the transmission will then shift into 5th gear without any clunking noise. The other thing that happens less often is that I keep 1st gear but I lose 3rd and 5th. Any advice would be appreciated.

 

[scotman]

Don't drive it with a tentative or feathering behavior on the throttle. The controller reads that as if you are wanting to slow down or stop. Drive it like you are in a bit of a hurry to get someplace.
When you drive a traditional manual transmission it requires the same deliberate actions. The Dual clutch transmission requires that same attitude from you.

 

[mark1022]

If I drive it like normal it goes into transmission fault immediately when it tries to shift into 3rd gear. Granny driving is the only way to get the transmission to shift into 3rd but will almost immediately go into transmission fault when I slow down to a stop and the transmission shifts down through the gears and tries to shift into 3rd.

 

[Handy Andy]

This may be more of a "calibration" if that step has not been done - it may help the system in determining the up-down shift point.

If this were to continue, the transmission is damaged - possibly caused by the previous condition doing that damage - you're just dealing with the failed/damaged mechanics of it. The shifter/servos can be replaced, but if the shift "syncros" are not - or they are damaged - then no matter the swaps and changes you try to do to the servo units - you still have this condition. Then that means it's the transmission.

 

[mark1022]

Yeah I figured that out today when I pulled two of the speed sensors out of the transmission today and found the tips of the sensors covered in metal shavings so it looks like something internal is bad. Thanks for all the responses.