How would i find out the gear ratio?
 

I'm 14, just got my first truck. 87 ford f250 4speed 4x4. When we were driving it home we discovered it's geared to pull over a house. In first and second it is slow then when u hit 3rd it goes. where on the truck would i figure out the ratio?

Drivers side door post there is a tag, post up the axle code here, someone will tell you what it is..

that tags on the back edge right?

right,,,,,,,,,,,,,,

it's got a c9 on it

there should be a tag on the diff cover...it has the info you are looking for

That's 3.55 limited slip.. Ford Axle Code Chart .: Articles

Since a previous owner certainly could have swapped in a different set of gears, here's what I would recommend:

Chock the front wheels, jack the rear of the truck up, and place jackstands under the rear axle. Put the transmission in neutral. Make a mark on the pinion flange (where the driveshaft connects to the rear axle) and a mark on the tire. Rotate the driveshaft and count the number of revolutions it takes to rotate the tire one full revolution.

3 1/4 turns = 3.27's or 3.31's
3 1/2 turns = 3.55's
3 3/4 turns = 3.73's
4 turns = 3.90's or 4.10's

etc. etc.

Grear Ratio
 

Mine says C5 on door sticker

Conanski gave you the link to find the answer.

C5 4.10. LIMITED SLIP
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Thank you
 

I saw the link now thank you very much, I don't understand mine says C5 but it shows a 1991 and showed that 1987's are C9's that's weird ;(.

Thank you, but do you think the years are switched around mine is an 87 not a 91, It shows C5's with 4.10 were 91 yr :(.

FYI...1st gear on that 4 speed is "granny gear". You really only need to use this when you need super low gearing for pulling power. 2nd gear is geared like your typical 1st gear, so under normal conditions you start out in 2nd gear, then shift to 3rd and 4th.

Well I checked my code and it lists as a 91 year when my truck is a 95. So i don't know about the year. but I assume, the gears are right regardless.

I was wondering why the truck didn't go anywere in 1st. gear lol then second was ok and 3rd was good phew thanx I think that will save me alot of gas hehehe.