How do I find out what rear end gear ratio I have on my 2004 Z71?

Thanks,
BOAT

in your glove box is a "RPO" code list... look for one that is similar to "GU6" or "GU8", then do a google search for GM RPO code list. the codes will also tell if you have limited slip rear end.

Ronnie,
Thanks a bunch.
According to the Glove Box, I saw a GT4 which corresponds to a 3.73 Ratio.
Is that good for towing?
Reason im asking is I was pulling my 16 ft basstracker with 4 guys in the tahoe and it was having a heck of time in tow/haul mode. it was always downshifting.......drove me nuts.

BOAT

With tow haul button engaged you have to be at a steady speed of 65mph are it will downshift back and forth to overdrive.

take the last 8 of your vin number to any GM dealer and they can give you just about any info on your truck. Usually Z-71's do have 3.73's and the non towing package trucks/suv's have 3.42's

Like Stan said tho make sure you use your tow/haul button when you pull the boat! One good rule of thumb is....if it down shifts more than twice on a hill then you need to slow down or pull it down into 3rd until you get out of the hills. One other point I would like to leave you with....When launching and recovering your boat pull it down into low 1. Normally in transmissions first gear is applied by 2 components. When putting it into 1st or low it adds another component and reduces the strain on the low/reverse sprag (mechanical diode) and will help prevent premature failure.