Just has the shift solenoid replaced about a month ago due to malfunction. They changed the fluid and filters in the transmission while they had is open. Truck ran great for about a month, and now it is down shifting hard when I coast. It is almost like a bump/jerk when it shifts at about 10-15 mph. It doesn't happen all the time, only when I get to about 40 mph and start coasting/slowing down. I have seen other posts with similar problems but haven't came across any definite answers. Was thinking about taking to the dealership to have the TCM flashed. Any suggestions?

 

still in warranty with it being an 07?

 

Nope, bought the truck used and the lifetime powertrain isnt transferrable.

 

Starting to think it might be the TPS sensor. When I start the truck it idles high (1400 rpm) then fluctuates between 700-1200 rpm. Turned it off and started poking around on the TPS sensor with a multimeter. Voltages read ok. Started the truck again and it did not fluctuate at idle. Drove it 10 miles and no hard downshifting occured...still doesn't fluctuate at idle. Maybe it was a loose connection and poking it with a multimeter helped??

 

Update: Has still been driving fine, no idle problems and no hard downshifting... I am completely confused.

 

It started again. The hard downshifting started Thursday morning on the way to work. When I parked I noticed my RPM's fluctuating like before. I didnt turn the truck off and I probed the TPS sensor again to get a reading. When I got the probes all the way down the idling fluctuating stopped and the voltage read correctly. I have been driving it since then and no problems. I think there is a loose or corroded connection between the sensor and the plug.

 

I dont know if this thread has actually helped anyone, as there hasnt been responses other than my own, but I have an update. I noticed my RPMs fluctuating at idle again and drove anyway. I was going 55 on an exit ramp when the whole truck shut off. CEL came on. Rolled to a stop and checked the code - P2074. Started the truck again and drove back to work. I just finished changing out the TPS sensor. I read another thread where someone had a similar problem. I will post again with results. I really hope it fixed it.

 

I was reading your post and wonder tps sensor solve your hard down shift. I also veiw some other post having transmission refashed. Just wanted to know the end results.

 

I have had the exact same problem with my truck. The tranny is rebuilt in it and it has a new fuel pump. A couple of weeks ago I was driving home and coasting downhill and it downshifted real hard a couple of times. Then started going uphill again and it completely shut off just like you said, but mine wouldn't start back up so i had to have it towed. Only thing they found wrong was the fuel pump so they replaced it. Thankfully bought a warranty. just yesterday it downshifted hard a couple of times again and I noticed the idle fluctuations while in park but not as severe as before. No clue what it could be.

 

ktulu61 I would suggest going ahead and replacing the TPS. I bought mine at the dealership for almost $100 but autozone has them for ~$35. It has been over 2 years since I replaced the TPS and I still have had no problems. It is just 2 torx screws that hold it on and it is easy to get to.