Here is something that I posted awhile back:
I decided to have a look at my TD-20 manuals. One manual appears to be an early version and the other a later version. Under the ‘Lubrication and Care of the Gearcase’ section of the earlier manual it states:
"Fill with MOBILGREASE UW or SEA-HORSE GEAR LUBRICANT No. 2…" and "gear lubricant can be mixed with motor oil S.A.E. 30 or 40 to make it more fluid; this, however, necessarily will have to be left to the discretion of the operator."
The later version of the manual had a little bit different recommendation:
"Mobilube GX 90 is recommended for best operation. In the event this is not obtainable, use any good grade of S.A.E. 90 gear oil suitable for automotive hypoid gears. In case of an emergency where neither is available, it is permissible to use an S.A.E. 40 oil, but only until such time as the proper lubricant can be obtained. Note: Sea Horse Gear Lubricant #2 or Mobilgrease "UW" were previously recommended. Either the grease or the hypoid gear lubricant may be used with satisfaction."
So out of all of that, somewhere late in the production run, it looks as though Johnson decided that the brass and rubber "CR or Garlock" seals were good enough for 90W hypoid oil. Grease or 90W? I guess it comes down to personal satisfaction/availability. Both are correct.
I was also curious about the "GREASE" stamping at the filler plug that was discussed, so I checked out my TD-20’s downstairs. To my surprise, two of the TD’s had the filler plug on the Port side with no writing, and two of the TD’s had the filler plug on the Starboard side with the word "GREASE". All of the motors are 1947 models, and believed to be original gear cases.
.
