OK... I got a question on drain plug locations

[da-choppa]

Looking at the Service manual for my 51 dated HG-42, the diagram and instructions shown for the location of the fill level and drain locations for both of the final drive locations are pretty vague.

When I rebuilt and cleaned my final drives and put in new seals and all, I never really did look much as I was completly draining and cleaning them out. Now that I want to check the levels, I am just wondering if I am actually opening up the FILLL LEVEL INDICATOR plug hole or the drain hole!

So, looking under the crawler, from the rear, I see a clearance hole thru the track frame, near the back of the drive, to access a slotted threaded plug in the final drive. I have to assume this is the FILL LEVEL INDICATOR  hole, and not the drain plug? its about 3-4 inches UP from the bottom of the drive casting. seems about right for the 1.5 pints of oil to come up to.

If my assumption is correct, and thats the LEVEL INDICATER HOLE, then where does one DRAIN the entire unit? Where is this drain Plugs location? Is it one of the lower casting assembly bolts perhaps?

I just cant see it anywhere.

like I said, I paid no mind when I had them apart as it was completly torn down and cleaned out and I just filled up with the recomended amount of oil, not really thinking much.. Now, as I have been running it, I would like to check the levels from time to time.

[da-choppa]

NOBODY knows this answer?

[hotratz]

Well, What I remember is there are two or maybe 3, 3/8th" pipe plugs on the back side, lower portion of the spacer (final housing) I justified that because you can index the housing biased forward or reverse the optimum location of the drain/fill will change places. I think I used the hole that was highest of all to fill. If I remember I'll look into it a little more. 

This is the only picture I have of the housing. I can see two plugs, one visible and the other accross from it behind a casting extrusion.

[da-choppa]

ah yes.. I know that the ONE plug I can see looks like a pipe plug. but dang if I can see another! My assumption, based on the angle of the finals when installed, is that the REAR plug MUST be the fill level indicator plug, and any plug closer ot the front of the diff would be the drain plug.

am I making the right assumption? Just I cant LOCATE said front/bottom most plug! Geez!

[John Schwiebert]

I will try to look over the weekend. Another thing that makes it bad is some of those 1951 tractors had later style final drives. It will probably be Saturday or Sunday before I double check.

[Jack in NB]

Mine have 3 holes with the plugs. They're all on the side of the casting. There's one on the very bottom for a drain, the one you see which is the fluid level gage, and a third.

I was told this was to accommodate rotating the final drive castings to move the tracks ahead or back depending on whether a loader or dozer was fitted. Whichever setup you had, you always had one hole as a drain, and one to check oil level.

[hotratz]

OK, Today I took a close look at the fill/drain plug configuration on the final housing from an OC-46 and also one off an OC-3.
They both had 4 plugs. If the housing is hanging straight down there will be a plug at  3:00, 5:00, 7:00 and 9:00. The reason there are 4 is as stated above, the housing may be indexed forward or rearward. Both 5:00 and 7:00 are drains, 3:00 and 9:00 are fills. You only use two of these plugs. The lowest of all is the drain and the one that ends up just under the level of the spindle is the fill. The other fill plug not used will be well above the level of the spindle. The reason they don't show up in the picture I posted above is the one at 3:00 is hidden behind the end of the spindle in the picture, The one at 5:00 can be seen, both the ones at 7:00 and 9:00 are hidden behind the casting contour where the cover bolt hole is located. Just pure chance that when I took the picture three were being hidden.

On my OC-46 the two correct ones line up with two access holes in the track frame (housing indexed forward) If I where to index the housing rearward I would have both drain locations showing up in the access holes and no access to the right fill level although it could still be filled with the hole that ended up well above the spindle. I would just have to know how much oil goes into the housing because I wouldn't have the advantage of filling to the hole level.  Obviously my track frames are correct for a loader so I'm wondering if the track frames for a dozer have access holes located differently.  

[oliverchris]

I have noticed that some rear sprockets on OC46s (and I have seen them rarely on OC3s) have one hole slightly enlarged for access - I presume to one or all of the filler holes...I will see if I can find a pic...if not I will take one.

[hotratz]

Chris, there is a plug in the drive shaft bearing cap that can be accessed through that big hole for filling. It is real high on the housing though so you would have to either know the quantity of oil you need or remove the fill indicator plug from the back. The other issue with that hole is if you buy new cap shims they may not have the fill hole punched in them. My OC-46 can not be filled from there anymore because of this. It's easier to just do it from the back side because you don't have to rotate the sprocket into position and you have to remove the fill indicator plug anyway.

[oliverchris]

Thanks for this. I have just picked up a nice OC46 with matching backhoe. Two engines - one looks great, other not so great. "Divorce forces sale" kinda deal...hope the OC46 wasn't the cause  

So next Winter's project is to check it over and put it all back together....am I the first to buy next Winter's project? - I doubt it  

Note: slave labor on engine lift  

[hotratz]

Great Find!

[Tim Ling]

Man, it's great to have a little one that is interested in an old tractor. My 3 year old grandson loves being in the garage helping me with my projects. We are looking forward to going to the annual tractor show at the fairgrounds this year. He knows all the brands and loves anything with crawler tracks.

[oliverchris]

and here's the backhoe unit