So for some time now, while driving, it seems that my transmission would not shift into 4th gear (auto trans). This only occurred between 40-45 mph. I did a lot of research and eventually went to the local AAMCO shop. They said they did a whole rebuild the month before on an identical truck with the identical problem with no success. After some more research on their part, they found a $60 item that did the fix. They were nice enough to give me the website and said if I bought it, they would put it in. Well it was easier then changing a battery so they lost out on an hour of labor and I have a great running truck.

The device is a noise filter. If you are not familiar, and I am no expert, the alternator apparently puts out frequencies that interfere with the transmission computer preventing it from shifting properly.

The customer service is great from this website and they have fast shipping.

http://www.trnw.net/estore/catalog/p...products_id=30

 

Interesting find. You post it in the Diesel section too?

 

No, not yet. I need to post it there and on the CumminsForum.