It would not switch gears when going 65

222,000 MILES • 5.9L • 6 CYL • TURBO • 4WD • AUTOMATIC
Avatar
CRAZYFUNMEXICAN
  • MEMBER
  • 2 POSTS
Have the truck listed above 2500 turbo diesel 24v. it would not switch gears when going 65 and it jerks back to 60 and then let it go and then right back to jerking back to 60 does it for 10 20 30 40 and 50. there is no engine light and I went to a mechanic and they cannot find nothing on their computer. I have changed 1 near the transmission oil transmission speed sensor, fuel filter, front and rear differential fluid, change the coolant radiator, water pump, then change the motor oil and filter. Please help me.
Oct 15, 2019 at 7:19 AM
Advertisement
Avatar
JACOBANDNICKOLAS
  • ✓Experienced Mechanic
  • 110,248 POSTS
Welcome to 2CarPros.

Do you mean that once at 65 it will not downshift? Do you mean it won't shift to overdrive? If you making it to that speed, it has to be shifting, so I am trying to narrow down what is happening.

There are several things that can cause shifting issues. Without a diagnostic trouble code from the transmission control module, it becomes a guessing game. For example, the overdrive overdrive solenoid may have failed or the torque converter clutch. These components are located on the transmission valve body which requires the pan to be removed. I don't want to suggest things and be wrong only to cost you unnecessarily. However, I will try to provide possibilities based on your answers.

Let me know,
Take care,
Joe
May 1, 2021 at 10:56 AM
Avatar
CRAZYFUNMEXICAN
  • MEMBER
  • 2 POSTS
Yes, downshifts I'm going to 60, 50, 40 and 30. here is the video
May 1, 2021 at 10:56 AM
Avatar
JACOBANDNICKOLAS
  • ✓Experienced Mechanic
  • 110,248 POSTS
Welcome back:

No problem with the delay. I did see it. Is it downshifting or slipping? If it is downshifting which is what you originally said, the first thing I would do is have the TCM re-flashed to see if that remedies the issue. Since there is no trouble code and it is acting like that, the problem may be the programming. Also, since it does this at shift points, it could even be a transmission line pressure issue, but at this point, I'm leaning toward the TCM (transmission control module).

Was the mechanic certified on this type of vehicle? Was he able to do more than just check for codes?

Let me know.

Joe
May 1, 2021 at 10:56 AM
Add a reply
Join 2CarPros for free, one of the most advanced car repair communities on the internet. From first-time drivers to seasoned mechanics, everyone is welcome to reply, share details, and get better answers. You can add a temporary image or video first; uploads are limited to 20 MB.

Frequently Asked Problems for This Vehicle