Quote:
Originally Posted by Bill
Your Ford dealer or a transmission shop could change the rear end to a higher-ratio unit (maybe something like a 3.73?) for a cost that won't hurt too much. It will lower your fuel economy a bit, but not much - and the reduced strain on your engine and transmission will probably make it pay for itself.
Bill
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As big and heavy as this series of van is, if you're not running AT LEAST 3.73's, it's not recommended for towing.
(Some info shows 3.92's to be the lowest ratio possible for towing.)
According to Ford's site, if you're running the 5.4L v8 with standard 3.55 gears, you shouldn't tow anything.
As Bill suggests, going with 3.73's or 4.10's will definitely help, and may actually INCREASE gas mileage while towing. (You'll probably suffer slightly when not towing.)
Without knowing what engine you're running, I can't quote for sure, but IF you have the 5.4L with 3.73's, the Ford website gives you at least a 6500 capacity. Even with this, going with 4.10's would give you more "grunt" and you will be able to maintain speed on the hills better.
I'm in the same boat.... my Astro has 3.23's which is not recommended for towing. By simply going to 3.42 or 3.73's, I'll get 5000 or 5500 respectively. Other Astro users have actually reported getting the same towing mileage after going from 3.42's to 4.10's, but now have much more "grunt".