Gear Oil Replacement

[TechnoSpark 0]

I have a 1964 854 Wheel Horse.  In the owner's manual, it says I need three pints of SAE 40 Gear Oil.  After looking around online for a while, I have discovered that you cannot buy SAE 40 Gear Oil anymore.  Does anyone have any recommendations as to what I should replace the transmission fluid with?

 

Thanks in advance!

[pfrederi 17,887]

It originally called for 40w Motor Oil.  That spec was changed to 90w gear oil later..

 

Welcome!!!

[WHX?? 49,177]

 

Best to remove the shifter and fill through there. Good time to check the dog point set screw and check the boot rubber.

[Racinbob 11,235]

The 40wt was recommended to help alleviate the shifter rails from causing it to lock up and it came out in a service bulletin. About that time they modified the rails so it was no longer needed. Actually, either would be fine.

[stevasaurus 22,872]

@TechnoSpark  Welcome to Red Square    The reason your 854 suggests 40wt is because of the suction that can be created between the shift forks in your transmission if you use 90wt.  I have the same problem in my 1962 702.  A quick explanation...you have 2 shift fork shafts under your shift boot.  1st and reverse work by sliding one fork when you shift.  You grab the other shift fork when you drop down to use 2nd and 3rd.  If you do not come to a complete stop when shifting (which you need to do), you stand the risk of creating a suction in one of the shift rails...which ends up in that you are stuck between the 2 shift rails and in 2 gears at the same time.  To fix this (and 40wt is no guarantee that this will not happen)...you need to lift up your boot and loosen the set screw and lock nut that hold in the shifter...you then need to use a large screw driver to pop the forks so that you end up in one gear. 

   I have had this happen 1 time in the last 10 years.  The secret is knowing this happens and to not shift on the fly.    With that said...I would use 90wt.

 

 

EDIT....Bob and I posted at the same time. 

 

[953 nut 55,851]

             When draining your transmission you will want to jack up the front end to ensure complete draining of the old fluid. The transmission case has a hump in the bottom that  will trap the old fluid.

[WHX?? 49,177]

 

39 minutes ago, 953 nut said:

transmission case has a hump in the bottom

 

Not mine Richard!

[SylvanLakeWH 25,973]

[KC9KAS 4,741]

@TechnoSpark 

[ToroHorse 5]

Conversion chart for ISO, AGMA, SAE oils:

 

 

 

40 weight engine viscosity is equivalent to 85-90 SAE gear oil. Gear oils have additives for the high pressures seen in the gear mesh. Hence the awful smell!

Edited March 5, 2018 by ToroHorse
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