Can the axel ratio be changed from a 3.23 to 3.73 on a 2010 GMC Serria with a 4.8L v8 2WD? If it can be done, what's involved and what's an approximate cost? I am looking to increase the trailer towing capacity.

 

What are you hoping to achieve?
Better launch while towing? or better MPG
Generally 4.8L isn't an ideal towing drive train. but it is doable.

Prices can very. Go to your dealership and get a quote, then compare with your local auto recyclers

If your familiar with ring and pinion installation I would continue your goal.
If your not familar with shimming and back lash I would leave it to a garage to rebuild your axle.

Welcome to TF

 

Yeah. What he said. You can replce the ring/pinion, but that requires some skill & special tools. Or you can find the complete 3.73:1 rear from a wrecked truck. Or better yet, a 4.11:1. You can swap over your brakes or upgrade. You may even be able to swap in a rear from a 1500 HD truck. It would most likely be 4.11.