EnzoColorado wrote:
OP here. I created a spreadsheet to calculate RPM at different speed (40 to 70 mph, increment of 10 mph) in different tranny gears with all the possible axle upgrade. That helped me to decide which one to upgrade. I'm coming from 3.08 so I had many options. If you want to PM me your email, I can email you my spreadsheet and you can change the numbers to match your vehicle.
If your Yukon is 4x4 you'll have to change from rear and front gear. That may affect the decision.
I can only use OD on flat ground, any grade and I'm pulling it down to 3rd. It seems happiest around 2800-3000 RPM and that is accomplished easiest in 3rd with the TC locked.
I used a calculator at Randy's Ring & Pinion to ballpark it, but I'll PM you my email.
It will be a junkyard axle swap for a couple of reasons. Cost is a factor, but in the process I can upgrade my semi-float rear 14 bolt to a full-float 14 bolt, which will carry the weight better. I am right at the line weight wise with my current setup and bigger is always better. It is 4x4, I'm aware of needing to change both. That won't be a issue, but I'll have to get with Blackbear for a re-tune.