Yes Rich .. There is a spinning brass bushing/ bearing in there that receives the square end on the drive cable . It spins in the die cast housing . In earlier ones there is a cap --looks like the drain on side of water valve but male . It is to oil that bush , via a small felt . It was greased at assembly but grease always gets dry and hard . It is often all that is wrong with speedo ( learned that the hard way -- after pulling apart whole thing and wrecking it the first time ) . That and atf into cable . Has to spin totally free at speedo head as if nothing is connected to it . I think if you have speedo out you can get oil into the space around spinning bushing by putting face down and putting oil around it into space while turning it . ( without getting the plug out ) WD 40 or penetrating oil might help , then like 10 weight . Or atf . I think you are right .. Later ones they greased or oiled and then put in plug like a core plug by denting center . Save .05$ . Any messing with inside of speedo head rarely turns out well . Very touchy to calibration .. Not just at one point , across whole dial can be ok one end off other end non linearly. I think but am not sure 1000 rpm there is 60 mph on all cars . ( actual number can be checked ) . I Used drill and whittled wood square like large toothpick to check ( approx) it worked ok after freeing it up . If friction there cable winds up a little against friction then snaps forward causing ~ 5-10 jump in mph number . Repeat !! Especially cold weather . Sometimes odometer is stuck or broken ( plastic !) much older ones are metal , mopar replacement parts , 50's -- at least once i used a metal one , nos off ebay to fix / replace that plastic one, but forget years that crossed . When odometer jams it usually breaks free from input drive by stripping a plastic gear in there , but sometimes can go snap , snap snap as teeth jump . .. Makes speedo jump very regularly , you can tell this one as Odometer does not move , eventually teeth wear off . Speedo works again after a while but no odo . Sometimes better to just accept that . If you get into the spinning magnet scraping etc , very hard to fix. That scraping shows as huge 30+ mph jumps off zero even when going slow . Can stop the scraping by careful bending but then calibration all off . At that point goes to pro if you have not by then wrecked it .. I think scraping is caused by wear in input bushing lets the part sag and hit . Half the magnet device is supported only by that same bushing . Has to stay square and centered . That sort if means it is worn out ?
Been there on these! Good luck !
Sent from my iPhone
On Nov 8, 2015, at 5:17 PM, 'Rich Barber' c300@xxxxxxx [Chrysler300] <Chrysler300-noreply@xxxxxxxxxxxxxxx> wrote: