How do I know what gears my truck has. everyone says 3.73s but I want to be sure. My truck is a 02 GMC Sierra RCSB with a 5.3L . any help would be apperciated.

 

Check the code listings in your glove box, look for the "GT4" code in the listings.If you find that then you have the 3:73's. If you see code GU6 listing you have the 3:42's.

 

thanks. later

 

Did you find out what gears you have?

 

I don't know if he did, but your info helped me figure out mine

 

mine too

 

A quick and easy way to tell is to drive your truck at highway speeds. If you are doing aroung 1800 RPM at 70, then you have 3.42s. If you are around 2100, you have 3.73s, and if you're higher than that..2300 or so, you have 4.10s

 

Yeah, my truck has 3.73s thanks for your help. I appreciate it. later.

 

the easiest way is always the rpo listing if the stock gear is still in there.

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

G80=Gov-Lock (Locking Rear Differential) Gov Lock explaination with video
G86=Limited Slip Rear (most commonly in quadrasteer trucks).


What rear comes in what:
1500: 8.6 10 bolt
1500 with quadrasteer: 9.75" rear (i believe this is a newer version of a dana 60)
1500 VHO and 2wd SS: 9.5 14 bolt (05' and newer)
1500HD: 9.5 14 bolt
2500: 9.5 14 bolt
2500HD: 10.5 14 bolt with 6.0L and 11.5 with 6.6L and 8.1L
3500: 11.5" rear

sport utilites:
1500: 8.6 rear
2500 9.5 rear with 6.0L and 10.5 rear with 8.1L

 

you dont have a pic of your truck? i want to see how different it looks from mine?