How do I tell what Gear ratio I have???

[BogeyBoy82]

Is it hidden in the vin somewhere or on the door or what?

I'm thinking 4.10s and a tune will really achieve all the performance I want b/c this thing is a pig off the line

 

[NathanJax]

It's in your RPO codes in your glove box.


Someone here might be able to tell you what to look for, or you can take your laptop to the truck and search for them on the net

 

[ChrisAU]

If they are the same as always GU6 is 3.42 and GT4 is 3.73...those may have changed since the '90s though.

 

[Sancho]

I think it depends on what transmission you have (haven't seen the 4.10s or 3.73s on the six speed,) but if you have 4.10s it shouldn't be a dog off the line.

Check the SPID label in the glove box:

GT4= 3.73
GT5= 4.10
GU4= 3.08 (these are the dogs, IMO)
GU5= 3.23
GU6= 3.42

G80= Limited Slip Differential; make sure you have that, too.

 

[ChrisAU]

G80= Limited Slip Differential; make sure you have that, too.

Do these things have a better reputation in NNBS trucks compared to OBS? I was extremely disappointed to find the code in my OBS truck.

 

[Sancho]

I don't know who manufactures the posi for GM nowadays, probably still Auburn, but you would rather not have posi? I'll grant you there are better aftermarket options, depending on your use, but I'd still rather have it than not.

 

[domin8]

Interesting

 

[ChrisAU]

I don't know who manufactures the posi for GM nowadays, probably still Auburn, but you would rather not have posi? I'll grant you there are better aftermarket options, depending on your use, but I'd still rather have it than not.

I can throw a Lock-Right into an open diff for $300 in less than two hours.

When the G80 goes it will take my entire rear end with it.

 

[Sancho]

How prevalent is that really though, in normal use? I've seen them wear out and just stop working (one tire fire,) but not blow up too often. Obviously, if you're off-roading with it there are better options. I'm thinking factory use is more for boat ramps and muddy roads, not rock crawling and mud bogs.

 

[ChrisAU]

Their reputation at FSC is less than stellar, for off-road and street trucks all the same. Hopefully mine will last a good while though!