Just found a donor car with a 3.73 with a saginaw 9.50 inch ring gear (RPO GT4-YO6-G80) What is the story on the saginaw rears??? Good, bad?? It is a disc brake setup....I just put a 3.23 rear in the car, am curious if it would be worth 250 dollars to buy this for the future...Thanks for any input guys...Tom

 

holy crap!!! a 3.5" ring gear!! must be rare!!!

sorry, other than that i cant help

i believe thats just a stock rear

 

where are you getting this 3.50 ring gear info from ??

it wil be a 7.5" or a 9 bolt axle if its the original rear end

3.73 is gm 7.5" ratio in these cars,

the rear end is GM if its saginaw

that would be the 7.5"

if its a drum rear and non posi and 3.73 then its worth up to 150 bucks depending on mileage


good luck

 

9.50 inch...typo guys.........

 

what car did you find with a 9.5" ring gear in it? Some trucks came with what's called 14 bolt semi-floater rear ends which weigh over 400 pounds, is this what you're contemplating to swap into your car? It's an 8 lug axle as well. I can't think of ANY cars that had larger than a 12 bolt ring gear in them which is still under 9" in size.

 

No its not a 8 lug, it is in a Z28...Im just telling you guys what the RPO codes say...I used the thirdgen decoder to do it, but maybe the code reader is wrong...I dont know, that is why I was asking, it seemed kinda odd to me...There were 2 cars sideby side both with rear disc, and one was 3.42, and the other 3.73...I took the RPO papaer out of both cars, and brought them home with me to decode at my leisure.....Here are the codes from one of them.... GT4-YO6-G80...what do yall make of it???? Thanks...

 

then they both are 7.5" 10 bolts. I would pop off the back cover to see if the gears are stamped 41/11 which would get you your 3.73 ratio because with cars these old, rears could have been swapped out.

 

the decoder is an error for Y06 its supposed to say 7.50

someone typo'd that


if its a G80 3.73 then its worth a bit more
but not if its a gov lok

but if it is then its not worth 2 cents

good luck

 

Hmm, I will check it out...Think I would like to have it just to keep it....

 

I came across an 86 T/A in the junkyard about a year ago that had the GT4 code on the sticker. I posted a question on here asking what ratio is was, and was told it's 3.73. G80 designates posi-traction, but like the other guy said, if it's a gov-loc, that doesn't mean much. The rearend was already gone in the car I saw at the yard, so I don't know if it was a 10 bolt or a 9 bolt. If the rearend you're looking at is a 9 bolt, technically the ratio is 3.70, not 3.73. Do you know if it's a 9 bolt or a 10 bolt? If it looks like the rearend that's already under your car now, obviously it's a 10. A nine bolt has a rubber fill plug in the back cover, and the cover itself is sorta shaped like a stop sign. I'm curious because I've always wondered if the GT code is for a 9 bolt or a 10. If the rearend you're looking at turns out to be a 9 bolt, the 3.70 ratio is extremely rare. Let us know what you figure out.