Review on Upgrade Your GM 12-Bolt Truck Differential with 🔧 USA Standard Gear (ZG GM12T-342) Ring & Pinion Gear Set by Ray Mcknight

These gears look good quality and the wear pattern after adjustment looks the best I have ever seen. I have an 8875 GM 12 bolt truck on the back of my '67 C10. All 3 of my C10, 67, 68, 69 2WD trucks had 3.08 gears installed from the factory. I think because my '67 and '68 only had a three-speed automatic transmission, it was better on the freeway. I have 69 years 3 manual transmission. Since I installed a 383 string small block and a 3000 rpm stall converter in the TH400, I figured that due to the cam profile, I would get the 3.08 speed wheel, a wheel with a 3.73 sprocket and would replace a spartan lunchbox lock. . I'll be launching this thing in a week or two. I'm just waiting in the machine shop to do a final piston adjustment so it's ready to assemble, plug it in, hook it all up, start it up and get my hat on. But I digress. Sorry, lost track. However, when shifting from 3.08 to 3.73, I naturally had to readjust the carrier to move it to the left. The factory seals were about the same from side to side. Left thickness 0.230, right thickness 0.243. I had to set the left side to 0.445 and the right side is only 0.024 spaced to get the 0.006-0.010 clearance needed for a good drawing. I even had to preload the gear another .030 to get it right. It's not as tight as it came from the factory, but I don't have a body expander and 3 very thin .008 shims fit without trying to flex on me. I don't think 0.004 inch will give me any problems. Especially with the Moser differential cover I use. Ok here is the problem I have. I had to move the carrier almost a quarter of an inch. , the right side of the carrier hit the area outside and in front of the carrier bearing hole. So I removed the carrier and used a Dremel tool to lightly sand the carrier housing at the four "corners" where the bearing is pressed in. I removed about .100" from each edge and it fit like a glove. I have up to 0.008 inch of play. Installed the fork with a new compression bushing and torqued the gear nut to 11 inches per pound. Reinstalled the carrier and tightened the covers to 60 ft.lbs and also installed the diff belt cover. Tip for your next diff rebuild: buy some cheap new gearbox bearings in addition to the ones you are about to install. Grind the inner ring of the cheap bearings so they slide over the gearbox without any pressure. This saves a lot of time and frustration when setting or adjusting the depth. When you're done, simply remove the dummy bearings and put the last good bearings in the gearbox. Oh, by the way, the Spartan Castle is a pain in the ass. for installation with differential housing in a car. If possible, remove it and place it on a bench or jack with the fork toward the ground. . Much luck