hey guys.......i have a 94 f150 4x2 5.0L aod-e.......i think i am currently running 3.08 gears. the tag off the rear cover reads 308 88 4b10. i was thinking of using 3:73, 30, or 4:10 gears. i do a lot of city driving with the occasional freeway. i wanted to use the 3:73 gears only cause of gas prices or should i step up to the 30. i wanted to stay away from the 4:10. what brand of gears should i use. motive, moser, richmond, ford racing or superior gears. has anyone changed gears to these gears and what were the results of the gear change and gas mileage. all input on this question is appreciated.............thank you.............

 

it was supposed to say three ninety gears. don't know why happy face is there. sorry for the screw up.

 

The happy face is there because when you put a : next to a 9 it converts it into a smiley. But gears are usually identified as 3.08:1 anyway.

What size tires are you running? Do you do any towing? If you have the stock 235/75/R15 tires then 3.73:1 would be fine.

 

You can plug in all your numbers here:

Novak Conversions - Gearing & Gearing Math for Jeeps

Tire diameter, axle and trans ratios. You can then see the difference in rpm/mph that a change will make.

Does your gearing feel too tall or have you put on larger tires? This won't be cheap. $200 for the gears, but the labor... Be sure to replace all the bearings while you have it apart.

 

Wouldn't shorter (numerically higher) gears hurt fuel economy? I thought the whole point of taller gears (numerically smaller) was to keep the engine at lower revs and increase fuel economy.

Or am I misunderstanding you and you want more power but not too big a hit to fuel economy?

 

the tires i am running are 275 60 15 rear and 245 60 15 front and i am looking for more power but not a too big hit on fuel economy rebuilding the motor has taken a back seat for now since i have lost 30 hours from my job since the economy tanked..................thanks for the replys..............

 

The higher ratio lower number gears are better for fuel economy with in reason. This is even more so with the older non overdrive transmissions. However, with overdrive transmissions the RPMs on the highway with higher gears are too low and the engine lugs and wastes fuel and performs badly.

As far as trucks with OD trans, I don't know why Ford put anything besides 3.55 and up gears in our trucks. The 3.08 and 2.73 are worthless for the most part. In my opinion the 3.08 gears are only suitable for the 300 I6 with stock tires.

 

I had a 3.08 gear with 27'' tires. Fuel economy was 16.9 mpg @ 70+ mph. Went to 4.11 gear ratio with 31'' tires. Fuel economy is 16 mpg @ 60 mph.

Wish I had went with 3.73.

 

hey guys thanks for the feed back..........i went on line to summit racing and saw a list of gears and now i was thinking of running either the 3.31 or 3.55 gears...........hey texas guy 001 hope you read this............ hows it feel running those 3.55 gears in the city and highway. i was leaning more towards running the 3.31 gears............thanks again for all the feed back............

 

My truck originally came with 3.08 gears. I think the 3.55 gears are great. Sometimes I think it would be cool to have 3.73 or 4.10 gears. For all around drivability and fuel economy the 3.55s are probably the best setup. I would think that 4.10 would create too high of RPM on the highway running 75-80 for good gas mileage. If I have to take the rear end apart on it again, I might consider going to 3.73. What size tires are you running?

 

Running at 75-80 with a truck is never going to get you good mileage no matter what gear you run, IMHO. I have 3.55s w/31" tires on my '92 F350 4x4 and a 5.8L engine. Those gears are barely adequate for my application. RPMs are ~1750 @65 MPH. Granted my truck is heavier and pushing extra drivetrain, but I see no reason to consider anything below 3.55 with any size tire on a truck. One of these days when I win the lottery I can see 4.56s in my future.

 

In general a 5.0 needs more gear than the 300 because it doesn't produce as much TQ at low rpms and because it can rev more, but a lighter truck will also get away with less gearing than a heavier truck. For performance select a numerically higher gear ratio, the AODE has a step overdrive so highway rpms still won't be too bad and the engine will operate at a lower load so the EFI will stay closed loop more and that improves milage.

Right now the motor turns about 1700rpm at 70mph and that's way too low for a 5.0.
With 4.10's is would be 2300rpm, with 3.73 it would be 2100rpm, and 3.55 is 2000rpm. IMO 3.55 to 3.73 would produce the best compromize of performance and milage for your truck.

 

what gear ratio would you recommend for a 5.8 and an e4od tranny I was looking into 3.55 maybe 3.73 what do you think

 

Need lots more info..
What truck model?
What is the tire size?
What is the intended use?
What are your goals.. performance or milage or a compromise of both?

 

92 F150 Ext Cab XLT compromise of both my tire size i am using is 31x10.5r15 but i am going to go to 33" tires sometime in the future
Also i may start using a gooseneck trailer (considering when i got the truck it had a gooseneck ball in the bed) I was thinking of upgrading my rear axle and suspension to handle the heavier loads