Hey I have a 97 F350 Dually 4x2 and I was thinkin bout changin the 3.73 to the 4.10 limited slip just wondering should I expect to experience any drastic mpg loss or high rpm's on the highway?

 

yes you will see high rpm on the highway its been so long since ive had my dually i cant remember what the rpm read at highway speeds. just know they are significantly higher than my 3.55 truck therefor mileage will not be as good but would be alot better for towing.. your truck will probally have 3.55's i beleive the 3.73 gears only came in superdutys could be wrong though. highway driving with my dually ranged mostly between 16 and 17 with the 4.10 and with my 4x4 with the 3.55 im seeing 19 to 21 mpg.

 

Your truck does have 3.55's unless someone changed them to 3.73's. They only came with 4.10's and 3.55's in these years. I'm in the process of switching to 4.10's right now. My rpm's will go from 2050 at 75 to 2368 at 75. I was getting 17mpg at 75 (empty of course), I expect it to go down 1mpg or so. However I really don't care as I tow 95% of the time with this truck and expect mileage won't suffer towing at all.

 

When I did the swap I lost 1-2 hwy mpg's and picked 1 mpg city driving. You just have to Change you driving habit

 

I have the 4.10 gears and since I don't tow anything big anymore, I am thinking of going to 3.55's. I am hitting 2600 at 75.
I am getting 15-16 mpg.

 

Sam if you wasn't so far away I know someone that would swap with you.

 

LOL, I would do it in a heartbeat. I still want limited slip though. I am not sure if the 3.55 will work on the 4.10 carrier.

 

His his a open diff. The 3.55 will work on your carrier

 

I will end up buying gears and having a buddy install them. With diesel over 4.00 a gallon, it wouldn't take long to break even.

 

I don't blame you. We're still at $3.69 a gl

 

How do you rate? Its over $4.10 in the mid west.

 

I was gonna stop and get fuel on my way to work Thursday morning, but decided to wait until I went home. It was $3.89 that morning. When I stopped on my way home it was $3.95!

 

Glenn this is the site we look at when we travel


Gasoline and Diesel Fuel Update - Energy Information Administration

 

Interesting site Mike. My only issue I have is: 56% of he price of diesel is due to the crude oil price however, we all know that diesel is a byproduct of refining gasoline. 62% of the gasoline price is for the crude oil. The same crude oil makes the diesel AND the gas but 62+56 does not equal 100%. Really gotta love the oil companies. LOL

 

I have a few sites bookmarked for diesel. But, some of these places had there head up their, you know what, when they designed the station. Its next to impossible to pull into some of them with a 35' camper and expect to be able to get out of there without backing up. I always try to fill up when I'm not hocked up to the camper or at the truck stops. I can go over 500 miles now with my aux tank, great improvement!!