Find a stock 3/4 ton with a sm420 and it should have the speedo drive gear you need
Just one wrench to remove it, might need pliers to undo the Speedo cable
And the inner worm style 4 tooth gear is the same for 3/4 and 1 tons with the same transmission
It’s surprisingly easy to pull out because it’s an open drive
Undo the universal joint cross and then the back cover has a few bolts and it’s all off
I recently replaced the rear transmissions seal on one of my 1 ton trucks and it was way easier than I thought it was gonna be. I think I did have to loosen the intermediate bearing holder to wiggle the drive shaft out of the way tho.
Also
Search eBay for the part number
Sometime people post nos parts in their original packaging by the part numbers with no idea of the application.
-s
