rockinkgin

Just had my 48re transmission on my 2007 Ram 3500 5.9 CTD 4x4 rebuilt and fuel mileage took a dump. Prior to rebuild I was getting 500-525 miles on a tank now I'm barely getting 400. Shop said it's due to winter fuel. I don't buy it as I've been driving it for 7 years and have always been able to get 500+ miles on a tank in ALL seasons. Any idea what might cause this?

Mikeske

Is your truck running in the same RPM range? Did you have anything else done at the same time, like tires, work done on the engine? If all things things are the same I would also attribute some of the mileage loss to the rebuilt transmission wearing in and also to the fuel especially if you in the prolong cold snap the midwest and eastern part of the country had recently. Wait awhile like later into the spring and see what the mileage is as we get into the spring.

rockinkgin

Thanks Mikeske, I did put new tires on the truck, but they are the same size and tread as what I previously had (Ameritrac to Continental). No mechanical repairs. A 20% drop in mileage seems a little excessive

Mikeske

Years ago I did had a automatic transmission rebuilt in my old car and I noticed about a 15% drop in mileage it gradually got better over a period of about six months. I don't now why but after awhile it did get better I think the new parts just have to wear into the transmission. Right after it got better then the gasoline went to the winter blend and it dropped by 10 or so. Waited until the next spring and it climbed back up.

rockinkgin

Thanks.