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Greetings I am in the process of changing the Transmission oil in my 42 160 three speed. The Shop Manual says that I should use 140w in the trans and also 140w in the OD and rear end 140w. I have some 85-140w but not sure to use that. The only other 140w I have found is "synthetic" and I don't want to put synthetic in. Any ideas of where to find 140w or can I use the regular 90w rear end oil. Thanks Dale

The 85W-140 gear oil you have should work well in the differential and transmission and overdrive. Just make sure it is GL-5 EP type oil or else the differential will object in a costly way. Many of us here prefer the 85W-140 gear oil for the differentials and transmissions in our Packards.

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Dear Dale

90w EP gear oil in the differential (GL-5) (85w-140 is fine)

140w non-EP in the trans - summer

90w non-EP in the trans - winter (if you drive it in the cold weather and snow alot)

If you have not drained the trans oil yet take a sample and compare it to modern gear oil. If it does not have a strong smell then it probably is not EP and you want to try 140w non-EP available from lubriplate. If the trans oil is nice and clean I would save it and reuse it to avoid a possible shifting problem. (you can always take it back out).

That's something I need to do on my 51. What is "EP"?

Thanks but I am a little confused. One comment says use 85 140w "EP" and another one say not to use "EP" or am I a little slow? Please clarify. Thanks Dale

EP stands for Extreme Pressure (additives). In a differential there is sliding action under extreme force so a special oil needed to be developed for Hypoid gears.

Old EP oils and greases are reactive to bronze synchronizers and so were not specified for the Packard transmission. In fact Bendix was very adamant that EP oil not be used in the overdrive. New EP oils usually satisfy the military spec MIL-2105 which sets a limit on reactivity. However lots of cars have been running around with EP oil in the transmissions for years so whatever damage there was to be done has already been done

Thanks for the info I am a little "wiser" with my Packard now. My Uncle use to say. " a little knowledge is dangerous" I am off the the Parts store.