Rear End Ratio?

Hi all,
Just bought a 2004 Trailblazer 4X4 with the 4.2L. Love the thing. I have the tow package but I can't figure out what rear end ratio I have. It's not on any of the information stickers. I got the numbers off the rear end. H231032441 is on the cover and 40035769 is stamped on the rear end where the drive shaft enters. Can anyone de-code these numbers or am I just not looking in the right place. I'm hoping I have the 4.10 for better towing or at least the 3.73. Thanks, mark

you have to find the RPO option for the gears. Then lok on your RPO list for which ever one matches.

Thanks for the info.

Look here (http://www.gm-trucks.com/rpolists/2004/Chevrolet/04_Chev_TrailBlazer.txt) to decode the RPO's

The RPO's are located on a sticker in the glove box.

C4D GVWR, 5550 lbs. (2517 kg)
C5N GVWR, 5750 lbs. (2608 kg)
G80 Differential, locking, heavy-duty, rear
GT4 Rear axle, 3.73 ratio
GT5 Rear axle, 4.10 ratio
GU6 Rear axle, 3.42 ratio

Thanks ZsTB. That really helped, I have the 3.42 rear end. GVWR is 5750 lbs. I'm going to be towing a car on a trailer. Total weight is going to be 4500lbs so I think I'll be fine. That 4.2 is really strong. Mark