I’m slow. I admit it. Have been reading about the conversion to a 4.10 rear end. Some have said it’s a direct replacement and fairly straightforward process. What is missing in my understanding, are the comments about the pinion gear.
I’m assuming that with this swap both the ring assembly and pinion gear are required? Is this correct? I acquired a 67-72 4.10 pumpkin years ago...that has been aitting on a shelf but the pinion is missing.
Hy tom moore, the pinion and ring gear are a matched set, if you have a differential center section with no pinion gear then the minimum you would have to do to install it would be to purchase a ring and pinion gear and have them installed and set up in your center section, hope that helps.
If you’re missing the pinion you’re starting from scratch on the hunt for another 4.10 pumpkin. You only need the gears I suppose, but you’re much more likely to find the whole assembly than to find just the matched set of gears.
Easiest way to do it is with the whole assembly. When I did the conversion on my 1-ton a loooong time ago I believe it was as easy as disconnect the driveshaft (can't remember what I did there) pull the axles out of the differential and then remove and replace the 5.14 pumpkin with the 4.10 unit. I didn't have a good shop setup at the time and did it with the truck on the ground. I'm sure there were some other minor steps that I had to do but can't recall off the top of my head. Made a world of difference after the switch. 55 mph didn't sound like I was going to blow the motor!
1959 Chevrolet 3800 Pickup 1937 Chevrolet GC Panel Can you still call it a barn find if it's your barn?
Have you read this tech tip? https://www.stovebolt.com/techtips/axles/1%20Ton%20Upgrade/ Part 1 step 3, the ring gear will have (among other numbers) 10:41 stamped on it. The number of gear teeth on pinion and ring gear; with some simple math this is the gear ratio. I don't recall what the pinion has on it for numbers but it may have a serial number matching one on the ring gear or something indicating the matched set.
thanks, I'll read that tip. I have more experience with these AD and pre-war torque tube assemblies than i do with an open driveline. After reading this, i made a mistake thinking the pinion gear was attached to a propellor/drive shaft ... like the torque tubes. In my haste I forgot that the pinion for this 68 differential was enclosed in the case with the ring, bearings and seals. To make a long story short, I’m all set and have a complete assembly.
