model 20 answers

how do you set up the end float on the amc20 diff using the orginal axles, I need to adjust mine up. any  help appreciated.

I would think there must be a slight preload on them or maybe a couple of thousandths free float. The shims are on the left side. I measured mine at .030" or .032" (one or the other) end float and was pretty sure that was way too much. I removed one of the shims (.030 or .032) so I have .002" pinch or free float, can't remember which.
I just read the TSM (recent acquisition) and they are calling for .004" to .008", .006" desired.
They say to seat it against the bearing cup using a lead hammer and measure the float with a dial indicator set up.

Good article on this AMC Forum. Mainstream medias often say the AMC model 10 and 20's are 'Dana' (spicer) sourced. As far as I know AMC made their own differentials. "Twin Grip" was the name for model 10 limited slip diffys. (model 20 limited slips were called...?) AMX390 tells us about that book I remember; "Performance American Style", a book made by AMC telling how to rebuild/hop up/modify AMC stockers for high performance/racing applications.

'Performance American Style' recommended to weld the cast iron center carrier to the steel tube axle extensions, and on four speed/man trans cars to weld on angle supports to the leaf spring perches... (I rounded the leaf spring pearches on my man trans 304 Javy, can only imagine a 390 or 401)

I think the Jeep guys know all the sources and how to's for the AMC model 20s?... Bulltear?

AMX Enterprises also sells one piece axles? -at least AMC diffys don't fall apart from a failed 'c-clip' like GM diffys do (with much embarrasment on the dragstrip! -I've seen that happen and laughed my rear off! -having the whole axle and wheel assembly come out the side of the car!)

The AMC 20 & the 15 were amc built . THE model 20 power lock  limited slip carrier was made by dana spicer. The same carrier style for the Mopar 8 3/4 , dana 60 , early Pontiac & Olds, early 10 bolt chevy were also dana. IIRC the 15 cone clutch was made by Borgwarner .

I have one of these with Superior one-piece shafts and a Detroit, also have a set of spare shafts (one-piece) but don't know how to go about getting bearing/seal set, I was told they don't interchange.