There is a plug all by it self to fill and check the fluid levels. It is on top off to the side it will take a 9/16 or 5/8s boxed end wrench. Steve

 

Should be 5/8's It should look like two nuts on top of each other.

The top on is 7/16 and its a brether.

 

If the fluid check doesn't solve the problem, clean all your electrical connections. Might want to check/replace your battery and plow cables as well. Old cables are a large cause of excessive resistance, which not only slows the pump down, but also makes your entire electrical system work harder.

:waving:
Mike(440trk)

 

What is the purpose of the smaller nut on top of the fill nut?

 

What is the purpose of the smaller nut on top of the fill nut?

The smaller "nut" is the actual breather/vent for the fluid reservoir..if you look at it closely, you'll see a small vent hole in the side of it.

The part your referring to as the fill plug is just a reducer bushing so the fill hole could be a little bigger than the thread size on the breather (makes it 1/4" pipe).. if the fill hole was the same size as the breather threads (1/8 pipe), it'd be a real pain to fill through a hole that small.

 

Check the two screen filters on front of pump body,