Engine/Transmission (1998.5 - 2002) Automatic Transmission Help

[rbsullivant]

I have a 99 Ram 2500 4x4, 47RE automatic transmission with a BD Power valve body and PressureLoc.

I was heading out of town yesterday pulling my 26' gooseneck trailer, but when I hit the hwy it wouldn't shift any higher than 2nd gear. I didn't get a check engine light and when I hooked up my code reader it's not showing any DTC codes. I did a search on the forum and it sounds like it's in some kind of safe mode.



What do I have to do to fix it??

 

[rbsullivant]

I found a thread that said they cleaned the negative battery terminals to fix their shifting problem. So I went out and cleaned all of the battery terminals and now it is shifting fine.

I still don't know what would cause it to not shift above 2nd gear, but disconnecting the batteries to clean the terminals must have reset something. Any ideas why? Should I still have it checked out by a transmission shop?

 

[JLandry]

Bob,



This symptom could be caused by a faulty transmission output shaft speed sensor. The PCM uses this sensor to help decide when to shift the transmission. Since it's easy to replace and inexpensive, it might be worth swapping out. It's located on the tailpiece of the transmission. A new one should be in stock at any good auto parts store.



Best regards,



John L.

 

[DavidC]

I installed a new tail shaft sensor in my 99. The old sensor read open across the terminals, the new one read 600 ohms. Before you replace you might check the resistance, could save you some money. It can be checked by simply unplugging the sensor and ohming across the pins.



Dave

 

[rbsullivant]

Thanks guys, I'll give it try!!