Re: Yellow Metal in a transmission or differential
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Forum Ambassador
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Scott - 3 transmissions used in the 9th Series; if your '32 Eight has the new 3-speed synchro transmission which was introduced in stages during the year (Light Eight and Twin Six first, Custom and Deluxe Eights last), then it has some yellow metal in the synchronizer rings as does the 4-speed synchro unit. The 4-speed non-synchro has no yellow metl to my knowledge though I've never had one apart. No yellow metal in the differential.
Not all GL-5 extreme pressure gear oils of today have the compatibility problem with yellow metals. I've used Valvoline SAE85W-140 GL-5 in Packard transmissions, rear axles, steering gear boxes, and overdrives for at least 25 or 30 years without any problems ever arising though I have in more recent years moved away from that practice. Perhaps it and some current formulations no longer have the issue but for sure the very first extreme pressure gear oils, long before the GL- designations were introduced, had sulfo-chloro-lead additives which were aggressive on yellow metals but were the Packard-recommended gear oils beginning with the introduction of the Angleset (hypoid) real axle. My best advise, erring perhaps on the side of caution, is to go with SAE 90 GL-1 for your steering gear box, Bijur and transmission, and multi-vis GL-5 for the differential. Here's the decal from an 11th Series rear axle (photo courtesy of John Wemple), Whitmore is still around and you might "Google" the name for more info. At least one of their EP hypoid oils still contains the sulfur compounds, though other EP oils do not. If you decide to call Whitmore and get some technical advise from them, I think many of us would like to hear what they have to say. From their data it looks like their Multi-Plus would be their recommendation today. whitmores.com/products/gear-oils.htm
Posted on: 2017/7/20 10:13
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