There was an article years ago on Allpar that talked about a Sheriff's Dept in California somewhere that bought new......I THINK it was 63 model Plymouths with the understanding that the same fluid used in the engine could also be used in the transmission. Chrysler put their stamp of approval for 30 weight engine oil for the transmission and the deal was struck. They never had issues. .......and I have looked and looked and LOOKED for that article and now I cannot find it. I believe it was a casualty of the Allpar web site redesign. They lost a lot of good stuff.
