HELP HELP HELP what gear ratio is this 9'' posi unit

i bought a 9'' posi unit and the guy sed in the craigslist add that it was a 375-1 gear ratio but it says 2.79 on the housing

i was spinning where the drive shaft mounts and was watching the gears where the axels go into and spin it untill the gears goes all the way around and i get about 3 spins to 1 rotation of the axel gears ?????? is this a 375-1 ratio or a 2.79-1 // 3.00-1

if it is not in the 375 ratio i need to take it back

 

sounds like a 2.79. Count the teeth on ring and the pinion and divide smaller number into larger, that will give you ratio. Depending on price, you may want to keep it and put gears in it.

 

i paid 350 for it

 

Did you double check for 28 spline? He may be passing off a truck 31 spline. Tough call on the $350, how much are rears going for in your neck of woods? Ebay use to have rebuilt (quality unknown) for under 500 with gear of your choice.

 

I bought an 81 Bronco 9 inch, 31 spline trac-loc 3.50 geared rear locally for $150.

 

yah i know e bay has them for cheap

i had to borrow $200from my dad to buy the thirdmember the only reason i bought it was because it had 3.75 gears and posi i dont want 2.79 it's way to low of a gear for my T-5 trans

the thirdmember gears are 16 and 41

 

41/16=2.56, way off the mark for what you were supposed to get.

 

whoops 44 and 16

so it's 44 / 16 = 275

 

Heck, junkyards have them for cheaper, $100 at my local yard.

 

yah i went back and got my money back

he is never going to get 350 for that 2.75-1 thats way to high of a gear

 

Are you sure its even a posi? Are the ring gear bolts recessed?

 

i didn't know if it was or not

i'm just glad i got my money back

 

Man i wish i knew all this information before i installed my rearend i want to check to make sure the stuff is legit.

 

Your stuff is legit..... (&$@#$!*)

 

Jack it up and turn one wheel. If the other spins the same direction, it's got a traction loc unit (or something similar) If the other wheel spins the opposite direction.............you got screwed.