1999 gmc z71 4x4 x-cab auto with towing package what gears should it have? 3.73? or 4.10s?

just wondering because my 38's and lift will be going on soon and I am skipping gears until funds allow for them

 

All the Z71's I have seen have had 3.73 gears on them. That does not mean they can't have 4.10.

 

I have only seen the 4.10's come on the 2500 series or the heavy duty ones with the 6.0 motor!

Some one posted before, a list of what the codes are. the codes are listed on a sticker in your glovebox. The codes indicate what gear you have. I can't remember the post title, but I would just search the forum for it!

 

Check your RPO codes with my list in the sig.

 

GT3= 3.42
GT4= 3.73
GT5= 4.10
Check the codes in your glove box.
Jim

 

GU4= 3.08
GU6= 3.42
GT4= 3.73
GT5= 4.10