Hey guys,

I have a '78 F150 Ranger XLT 4x4 with a 4-speed manual (granny gear). The truck is geared so damn low, in first gear in 4-low I have a max speed of like 2 miles per hour. Needless to say, at highway speeds in 2-high I am sucking down the gas.

Does anyone have an idea what the gear ratio is in this truck, or how I can find out? Also, what kinda gears should I think about switching to in order to increase mileage and make highway driving less stressful on the truck? Whatever I do, I figure the granny gear in 4-low is going to be low enough to drag the average chevy around town ...


take it easy,
maharashii

 

Hey guys,

sorry about the crappy subject line - somehow it got posted without including the descriptive "gear ratio" part. Anyhow, any ideas? I looked through my owners manual but it didn't mention anything too useful ...

take it easy,
maharashii

 

I know my 78 4x4 has 3:50:1 ratios in both front and rear axles. Yours might be the same. Just find the tag on the front and rear diff. and look at the first 3 numbers on the top row. That will tell you your ratio. Now as far as improving your gas mileage with different gears,that..... I'm not too sure about. Hope this helped some.

 

"Granny" low is s'posed to be that low. Even if you had taller gears you still wouldn't be able to go over about 5 mph without winding the motor too high. The 1st gear ratio is around 6:1 vs. 4th which is 1:1. FWIW autos are generally 3:1 in 1st and 1:1 in 3rd.

I doubt you have much higher than 4.10:1 in your truck which was fairly common, you could switch to larger tires, effectively raising your gear ratio, or switch to lower 3.50:1 gears. If you plug in the VIN and axle codes on the website below it will tell you the gear ratio or you can look at the tags on the axles themselves.

http://www.medicine.wisc.edu/~mrm/bronco/ftvin.cgi

 

you shouldn't be using 1st much anyway, unless you pull a lot of heavy loads...the purpose of 1st in that tranny was to get initial momentum when the truck is pulling large loads...otherwise, it is meant to be used as a 3 speed....i have a pickup with a granny, and 3.50 gears...i ran 31, then switched to 33 inch tires...made a small difference in mileage, but if the tires were any larger, then taking off would suffer big time....

 

 

[font size="1" color="#FF0000"]LAST EDITED ON 14-Jul-01 AT 01:13 AM (EST)[/font][p]Thanks for the website and the axle tag tips - i'll check those out.

I rarely ever use 1st gear, I guess i was just trying to make a point about how low the truck is geared.

anyhoo, I'm just looking for a little more cruising speed / mileage for when i hit the highway ...