02/20/2026
Update on the courier. Yes, it’s going up to the next level. Wild! In preparation for reliably handling 40” tires, the first step is gearing. The 4.30-geared excursion axles we pulled out of the junkyard several years ago were great with 35s. Still got the job done with 37s. But fell flat on their face offroad with 40s. Regearing is the perfect time to install lockers too. We are tossing the ol’ lunchbox- style locker which has been a champ, and been really good to us, and upgrading to a Yukon Grizzly locker which should be pretty much unstoppable in the Sterling 10.5. The open differential up front has made it so we have failed to conquer many obstacles in Moab. As you may know, the superduty Dana 50 monobeam front axle shares many things with the Dana 60, with the benefit of being much cheaper to find, which was a huge factor in the initial build of the truck. The inner axle shafts on a Dana 50 monobeam neck down right at the pumpkin, making it slightly weaker. Slightly fewer spline count, too. We diddnt want to go full lock in the front and risk blowing an axle shaft or axle shaft u-joint, so we chose a limited slip unit. If we lift one tire in the air, slight brake pressure on the front axle will force the limited slip to put the power to the tire on the ground- exactly what we want! Having the limited slip instead of a full on locker should prevent broken parts and headache in the future.
Other supporting mods for 40” tires include a hydro-assist steering setup with a Saginaw ported power steering pump, drilling and tapping our IFS Toyota steering box for hydro assist, and swapping out fenders and the bed for some “patina” components we don’t mind smashing with a hammer and cutting with a angle grinder to gain clearance and allow the tires to go full flex without causing tire or body damage.
