option code ?
 

Can anyone tell me the rear ratio with just option code. G80 is the code for the posi unit. Dont want to pull the cover unless it is necessary. Thanks

On a 1/2 ton truck, models with a standard 6-cylinder (or small V8, 283/307) engine usually had factory 3.73 gears. 350/327/396/402 equipped trucks usually had 3.07 gears.

Its not that easy to tell but... if this is what you want here it is for 1/2 tons.

H01 is 3.07
H05 is 3.73
H04 is 4.11

If you dont have any option code listed it probably has the standard equipment... most like if it s a 6 cyl it's 3.73 if its an original 8 it's more than likely 3.07

OK, this is a 1/2 with factory installed 350. I was hoping the option code G80 on the glove box sticker was a clue for the ratio. Guess it just means positraction rear.

Rod, Those numbers you gave are they the ones on the id tag on the rear housing?
Thanks guys.

Jack up the rear end and put a mark on the drive shaft. Turn the right rear tire 1 revolution (if you have a posi) or 2 revolutions (for an open) and count the drive shaft revolutions. This will get you in the ball park.

Paul

if its an original 350 truck i will bet it has 3.07's if not it would have the optioned listed for 3.73 gears.

There is a series of numbers on the top right hand side of the axle. The first 3 letters will be the numbers that you need to decifer the gear ratio and wether or not it is a possi. WES www.ClassicHeartbeat.com

Re: option code ?
 

Who was the manufacturer of these axles? My 6 Cyl. Has the G80 code as well thanks for the info!

Re: option code ?
 

GM build the 12 bolts. They weren't outsources. Was the original posters truck a 4 speed or automatic transmission?

Re: option code ?
 

But the OE positraction units were.......Spicer? Ugh, I can't remember.