i have a stock truck. its an 86 f150 4wd. with the 302 longbed lariat how can i tell what gears i have. its the h3 axle if that helps

 

H3 in an 86 is 4.11's with a limited slip rear, most likely an 8.8". With the old Ford 9 inch, it's 2.75's which I doubt you have.

 

ok my axle is solid axle with no rear cover full punkin. so what gears would that be

 

I dunno - but we can do math to get the gear ratio.

What transmission do you have, and what is your tire size? Is your speedo close to accurate, and do you have a tach?

 

No Diff cover... does it have 10 nuts on the front to take off and the diferental pulls out the front of the axle? if so thats a 9"...

 

ok i have the 9inch rear end then. tires are stock i know that i dont remember the size off of my head though. transmission has 1s drive and overdrice and has tach and speedo and both are accurate

 

Okay - take it out on the highway and cruise with it in overdrive with the converter locked. Note the speed and RPM and post it. I'd recommend that it be at least 60 mph. While you are out there, read the tire size off the sidewall. I'll run the numbers through a calculator.

 

is the tag gone off the rearend? should be a tag attached to one of the bolts holdin the carrier in

 

ok i was at 75mph at 2200 rpm. in overdrive anyone have a clue?

 

you could have just jacked the rear up and put the truck in neutral. count how many times the driveshaft spins to one revolution of the tire. that is your gear ratio.

post what you got if the driveshaft spins a little more or a little less than a full number, which it will.

 

im just posting like the guy told me to

 

Confirm that the torque converter was locked up (this is very important), and I still need your tire size. If it's 4.11's, that would be a 31.5" tire. It certainly isn't 2.75's, but someone in the past must have regeared it if you have a Ford 9" rear. 3.73's would be a 28.6" tire, and I *THINK* that would be closer to stock than 31.5. I don't know offhand what other ratios were available for the 9 incher.

Sorry for the delay, I'm on an extended road trip and don't have much time to hit the forums. This is the calculator I used:

http://4lo.com/calc/gearratio.htm

Your AOD has 0.67 ratio in OD and use 1 for the TC ratio.