how do you check this oil in the final drive unit out by the rear wheels?
1-any fill plugs
2-any drain plugs
3-type of oil to use

this is 1956 farmall 100

thanks bob

There is a fill hole with plug on the inside of each final drive housing. It will have a square socket hole in it for inserting a square wrench to remove the plug. It's just like the fill plug on top of the transmission. If you have implements bolted to the drawbar bolt holes, the plugs may be behind those. Fill to the bottom of the hole. There is no drain. You have to remove the pan. Get new gaskets before you do that. Use 90W gear oil to refill.

If I just wanted to check the oil I would remove the quick detachable drawbar along with the swinging drawbar and see if you don't have oil fill and level plug behind the plate that mounts the drawbar to the axle housing.This is just a guess but seems to me that is the way the super A is made.

Bob, Not sure about the 100 but on my 64 Cub and 45 A, the covers on the bottom of the finals have no fill holes and no drain holes. Just remove all the screws and drop the pans. You may want to have a set of new gaskets to install just in case the old ones get screwed up in the removal process. I'd use 90w gear lube or 85w140 and I fill mine about 1/2" below the top. Carefully lift the cover back into place and start a couple of the bolts at opposite ends. Then put the rest of the bolts in and draw it up even. Leaving the lube below the top helps eliminate any leakers you may have and the bull gear still is submerged to carry the lube up to the bearings at the top of the final drive. G'luck.//FB