Hi Im new to this forum and I have a question that may have been asked but I have a 88 F150 with a 5.8l and 3 speed auto transmission, and my question is there a way to put a auto with overdrive? because when you drive it it shifts perfect but it could use another gear, I get terriable gas mileage and Im sure its because of the three speed auto trans...
Thanks

 

Not an expert but two possible transmissions for your truck. One is the AOD but you would probably have to get a heavy duty rebuild done on it for your engine.
The other is the huge E4OD but it is computer controlled so you would need a stand alone controller at big $.
Both would bolt up but would probably need cross member mods and driveshaft mods.
The trans you have will be the C6 which is almost bullet proof. Have you thought of keeping it and changing the axle ratio?
Another possibility is an overdrive unit to bolt to the C6 but big $ if buying new.

 

I just bought the truck its a 2wd and not any rust its very solid, I thought I would drive it back and forht to work (32 mile 1 way) but at 3.00 a gallon it would cost me around 25.00 aday... so changing the gear ratio would be a option, not sure what ratio is in truck but when driving and let off gas pedal the truck starts slowing down fast...
thanks

 

Ford Axle Code Chart .: Articles Here is a link to a chart. Check what the axle code is on your door sticker and match it with the chart (it says for `91 but will cover your truck).

 

the C6 and AOD use the same cross member so no mods are needed

ford was actually smart with the cross member because they stamped what transmissions can be used with it...

the C6 AOD and M5OD use the same cross member

 

thanks guys Im sure the swap would intel more than unbolt C6 and rebolt aod, but Im not sure

 

Keep in mind you'll still be near $20 per day even with OD.....

 

lol well 20 a day is better than 25 a day

thats 35 dollars a week

$1820 a year....

look a new set of tires

 

I think the AOD would be your best choice , you don,t need a computer to run it , with a shift kit it should be fine , or you could get the gear sets & input shaft out of a 4R70W & put it in the AOD , it would give you a better gear ratio & make it stronger....Lew

 

Am I figuring this right, you are getting about 7.7 mpg?

$25 worth of $3 gas = 8.3 gallons.

64 miles / 8.3 gallons = 7.71

A 20% increase will equal 9.25 mpg.

64 miles at 9.25 = 6.9 gallons

6.9 at $3 = $20.70

I suppose if you can make the swap for under $1000, you'll be "ahead".

Of course, a 35 mpg car would take 1.83 gallons per day, for $5.49, and the $19.51 per day savings becomes $97.55 per week, $4877.50 per year.

Back to your truck. Find out what axle you have first. Are you going to tow and haul? You have the dreaded 8.8 axle I think, which makes ratio changes more difficult than the old 9 inch. If you are geared really short now, maybe an axle change would help. Your mpg seems very low even for the set up you have, so perhaps a "tune up" and check of the running condition is in order.

 

my 5.0 with a c6 and 3.08 gear gets about 14.5 mpg

of course its 2wd reg cab short bed....

only mod ive done is an e-fan.... and synthetic oil... the last time the plugs was changed was like 2 years ago and it was replaced with cheap stuff

i wonder what an AOD will do for it....

 

Make it worse.. unless you also change to at least 3.55 gears. The 5.0 needs a little more rpm to maintain HWY speeds while the 4.9 and 5.8 can pull higher(numerically lower) gears.

An AOD would be the best solution for the OP... maintaing towing power while roughly doubling the highway milage.

 

xD i ment to say aod will do for it at 3.73 gears haha... but i got side tracked when i remembered the e-fan and oil lol

and the 14.5 mpg is on like back roads where the rpm is isnt consistent