I have a 99 expy with only 73,000 miles, well i have 2 questions, first

When im driving on the city i always use the O/D off, and well, when i go easy on the gas (drive slow), you know to save some gas, the trans shifts right from first to second, then it runs and it seems like it revs down a little, and then runs again and makes the second to third shift, everything feels fine, but when i do the same but i go a bit harder on the gas i dont feel like it revs down. what would the problem be???

and sometimes when i drive and i completely stop (red light or something) the truck revs down beyond the 500 rpms, and it kinda rattles, nothing to be scared but i just want to know what would it be.


thank you yall

 

no one knows what im talking about?

 

Why do you turn the overdrive off in the city? It's gaining you nothing. If you're not going fast enough for the truck to need to shift into OD, it won't. Why go through the trouble? Besides, if you ever exceed about 42 MPH in the city, letting the truck shift into OD would save you gas.

 

Sounds as if the torque converter is possibly preparing for the shift. I would not worry too much about it. As another stated you really dont gain anything by keeping O/D off. The computer knows at what point the truck can go into overdrive and will allow it to do so saving gas. Only really need to take O/D off when towing or when going down long hills so you can benefit from some compression braking

 

well the guy from the ford dealer recommended me to turn the OD off when driving in the city, because i live in dallas and u know traffic jams are everywhere, he told me only to turn the OD on, only when im driving on the highway or freeway,.

ohh my bad, so thats the torque converter, i thought that my automatic trans was a 5 speed instead of a 4 speed, cause thats how it feels, it feels like another shift between second and third speed.

and what about that, when i totally stop it feels like it revs down, and it kinda, and i mean KINDA rattles, when it does that.