Calling all Chevy Mechanics (HELP!)

[royal0014]

Gotta 1995 S-10 4X4, ext cab, 'Z" motor. Having problems w/the front end, long story there. But, I have a chance to pick up a used one for little of nothing, but I need to know the gear ratio of my rear end to match. Problem is, the tag that should be on the rear housing to tell you what gear ratio it is is not there. I know there where two ratios used, but don't know which is in my truck.....

Is there a way to find out, such as the codes in the glove box? I did a vin search but that didn't help.

Thanks to all......

 

[ajgraz]

Re: Calling all Chevy Mechanics (HELP!)

Does the RPO codes sticker in the glove box have any of these codes on it?

GU4=3.08
GU5=3.23
GU6=3.42
GT4=3.73
GT5=4.10
HC4=4.56

G80 - locking differential

 

[royal0014]

Re: Calling all Chevy Mechanics (HELP!)

Yes, GU6 for 3.42 ratio, but I need to know if it's 7.5 or 7.625 ring. Thanks for the reply

 

[ajgraz]

Re: Calling all Chevy Mechanics (HELP!)

Post-1990 or so, all the 7.5's were re-named "7.625," so if that's what you have, it's officially a 7.625"

But, the 90's S-10's with the 4.3 ("Z") engine could have come with the 8.5" as a factory option.

So do you have either of these codes?

G87 Ring Gear, 8.50 Inch
G89 Ring Gear, 7.50/7.625 Inch

Alternatively, which of the gaskets in the upper row left matches the housing?

 

[royal0014]

Re: Calling all Chevy Mechanics (HELP!)

Been researching for hours. I have seen the chart you have, definitly not a 8.5. But I find conflicting info on 7.5 vs 7.625. The only RPO code I have is GU6 for 3.42 ratio. Found RPO code list and tracked down all that are printed in my dash, no list for ring.....

Probably is a 7.625, but I can't nail it down positive

Thanks for the reply