My 4.6 is a weak engine
Senior Member
Joined: Mar 2000
Posts: 685
Likes: 0
From: Cincinnati, Ohio
Go with the 3.55 gear. Check out some of the
mustangs sites, they have gear ratio calculators, so you can see the difference
between gearsets. You need to know your tire size and transmisson gear ratios.
"Don't fear the gear"
mustangs sites, they have gear ratio calculators, so you can see the difference
between gearsets. You need to know your tire size and transmisson gear ratios.
"Don't fear the gear"
Senior Member
Joined: Mar 2000
Posts: 306
Likes: 0
From: Prince George, BC Canada
I think the 3.55's are fine also. Currently I get around 19-20 mpg on the hwy and around 13-14 in town. Those are in spring, summer and fall.
In winter, when the temp goes down to -8 F or colder, well that's when I wish I still had my Firefly.
In winter, when the temp goes down to -8 F or colder, well that's when I wish I still had my Firefly.
Senior Member
Joined: Dec 1969
Posts: 343
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From: Jacksonville, FL USA
Larry,
If you have the 3.55 set already, then by all means use them. Personally I don't think the 3.27s would be that much of an improvement over the stock gears. Ford doesn't offer the 3.27 gears stock, so if you upgrade from the factory you get 3.55's. My truck has the STX sport package which came with 3.55 gears as well as 275-60R17 Eagle GT II street tires that are around 31 inches tall. I still can get around 17 to 18 mpg on the highway with the 4.6L engine. The only time I have noticed the transmission doing what you have experienced has been when going up a pretty tall bridge over the intracoastal waterway here in Jacksonville, FL.
If you have the 3.55 set already, then by all means use them. Personally I don't think the 3.27s would be that much of an improvement over the stock gears. Ford doesn't offer the 3.27 gears stock, so if you upgrade from the factory you get 3.55's. My truck has the STX sport package which came with 3.55 gears as well as 275-60R17 Eagle GT II street tires that are around 31 inches tall. I still can get around 17 to 18 mpg on the highway with the 4.6L engine. The only time I have noticed the transmission doing what you have experienced has been when going up a pretty tall bridge over the intracoastal waterway here in Jacksonville, FL.
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Senior Member
Joined: Jul 1999
Posts: 186
Likes: 0
From: Sugarland, TX USA
2000 F150 4x4,
I have gone through the numbers and in 3rd(OD off) with the 3.08 I am turning 2402 rpm at 65 mph. With the 3.27 I would be turning 2550 and the 3.55 2769. Again my towing power in 3rd is fair so the 3.27 would improve that and still keep the rpms down from the 3.55. I feel pretty certain the 3.27 would solve the unlocking in OD at highway speeds over overpasses too. But I have a 3.55 sitting in my garage waiting to go in. There may not be a gear to correct the speedometer with the 3.27 so the 3.55 would be the only choice. I'll have to check with the dealer.
I have gone through the numbers and in 3rd(OD off) with the 3.08 I am turning 2402 rpm at 65 mph. With the 3.27 I would be turning 2550 and the 3.55 2769. Again my towing power in 3rd is fair so the 3.27 would improve that and still keep the rpms down from the 3.55. I feel pretty certain the 3.27 would solve the unlocking in OD at highway speeds over overpasses too. But I have a 3.55 sitting in my garage waiting to go in. There may not be a gear to correct the speedometer with the 3.27 so the 3.55 would be the only choice. I'll have to check with the dealer.