big heads up , on this: not going into reverse ( if linkage is set right) can be caused by reverse lockout set up . I had my valve body etc in and out twice all was fine ; even different one , it still did it . So: The reverse lockout prevents engaging reverse if car is moving , a pin moves out, blocks R if car is over like 5 mph to avoid disaster if you hit R button by accident at 60 mph . So it determines this “ stopped car “ by governor pressure going very low . But 300C , in my case the governor pressure did not return to almost zero when car was stopped Discovered by accident that pressing D first , engaging , then hit R it would go in every time . I think pin did not have time to move / block as the trans moved around a lot of stuff going D to R I found this description of how it works in a(?55 or 56) powerflite book , as at the time I was reading all I could find on cast iron trans over thus R issue . A lot of good explanation stuff was dropped in the later service manuals . Why this post, recently I saw an old service bulletin on the 57 trans where techs had been previously instructed to “ file a taper on the gov weight “ over this, and that this was no longer necessary after xx date in 1957 as mopar had “ corrected the problem” with the governor returning to zero The bulletin said nothing about what that filing was doing or how , or what the charge was, but I could imagine relieving the weight when near the stopped position might let psi drop more at that end of travel . And governor in 300 was already special , ( favoring higher rpm) maybe it was not fully baked when sent out . Anyway car is still like that , — pulling valve body or trans in and out a 4th time was too much .Maybe some day … So check the gov pressure at idle — if no reverse , try D then R I doubt fluid type would impact valve body or control system , the changes in fluid were more about friction modifiers / clutch material changes, hi temp stability, seal life, gear lube etc That said , although i do use type F —I think that is the recommendation for A today ,— out of caution, — I do wonder if the latest and greatest stuff is better , for sure it is in some parameters, but may not work right in others .., A test someday ,or somehow get more engineering info? Japanese cars do not even have a trans fill place now, it is “ sealed for life of car “ . A magnet in pan is smart, too . I have that in 02 jeeps twice now , it picks up metal dust for sure , both went 300K Same in axle plugs . I also note the old fluid drive used straight 10 engine oil , specifying no additives . ( in a 51 Imperial that crossed my path) It had a fluid coupling , maybe an early torque converter (I don't know) but the point is atf started as 10 W (?) and stuff was put in to make type A — standardized by GM which they all used for a while. Manual transmissions now use atf or 10 , not the heavy “ gear oil” i remember used in manual trans of 50’s . That says opinions at the big guys move around . Not rocket science , in a way . PS fluid must be along these lines , if a worry , use what is labeled as PS fluid . But the atf additives cant hurt it ? just not needed ? On Aug 4, 2025, at 4:18 PM, aswygart@xxxxxxxxxx wrote: -- For archives go to http://www.forwardlook.net/300-archive/search.htm#querylang --- You received this message because you are subscribed to the Google Groups "Chrysler 300 Club International" group. To unsubscribe from this group and stop receiving emails from it, send an email to chrysler-300-club-international+unsubscribe@xxxxxxxxxxxxxxxx. To view this discussion visit https://groups.google.com/d/msgid/chrysler-300-club-international/90AC4ACD-8296-4775-A291-173428263F51%40gradyresearch.com. |
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