Re: Installing a 424 Swiftamatic in an L
I have done the conversion to a 58 LI so I did not have to swap the lead worm. Doing the conversion on a L8/C8 will require removal of the advance casting and engine. That is needed to remove the eight lead worm and install the six lead worm.
The differential from the 400 series will fit right into a L8/C8 if they have the same cog shifting components. The early models were 5 cogs and the later models are 3 cogs. You must keep the shifting clutch from the L8/C8, the shifting clutch from a 400 will not work in a two-wheeler, nor will the thrust pin in the center of the differential. The 400 series thrust pin is shorter than a two-wheeler. There could be a left side bearing difference between new differential and old, there were changes, but you can either swap the left side of the differential or the bearing itself.
As far as the axle housing shims, you probably have enough with two new axle housing gaskets. The shims are used to adjust the 008 - 012" end play on the differential and best done without one or both axle shafts in place. Bolt the axle housing down with new gaskets and shims using three bolts in a triangular pattern. You now reach in the advance casting opening with a long pry bar and try to wiggle the differential side to side. More than a wiggle is too much, remove shims. As the differential carrier bearings worked over the last forty to fifty years, they wore a tad, hence fewer shims needed to achieve end play. If you think you might be too tight, just reach in a try turning the lead worm by hand. It should turn the differential with ease.
Next you install the axles and bearing caps. Make sure you have the thrust pin in the differential. The length of a two-wheeler thrust pin is 1.250, if your pin shows a lot of wear, replace it. The axle end play is also 008 - 012" but it can all be adjusted from one side. That is done by adding/removing shims behind the bearing cap. Remember, if the thrust pin is worn, then axle end play will require more shims. Just push/pull on one axle shaft and look for that wiggle. It is a great time to replace leaking axle shaft oil seals, but they run about sixteen dollars each and you need two per side.
Good luck, Roger
Faux Pas are my forte
Last edited by beaner2u; 04-10-2019 at 09:16 PM.