What to watch for on the H for rear end Oil change??

Hi All... I am knew at owning a Farmall H 1942. I would like to hear from you folks
that have many more years of experience with the H series Tractors than I ever will.

I would like to change the Oil in the rear end of the H just below the PTO only because
I think it needs it, and I have know Idea if it has ever been changed. So to start out
knowing when these fluids have been changed I would like to change it.
I see the drain plug under the PTO. I don't know how many gallons I should put in or what type of oil.
I have two Manuals that I purchased for this Farmall H the TC-27E and the Operators Manual Farmall H and HV
Tractors. Can some one point me in the right direction for the proper Manual on what type of oil goes into
the rear end of the Tractor?? Thank you for your reply...Ron (Maine)

It holds approx 6 gal. Plug on left side in front of clutch pedal is level. I used mineral 90 in the one am working on.

If you've got the operator's manual, it should tell you how much and what type of oils to use.

As I recall the rear end holds 7 gallons of your favorite heavy gear lube.

Thank you Barnyard for your reply. I have been searching the Operators Manual and have now
found that its called "Transmission and Differential case". I was looking under the wrong
terminology... I thought it might have been Rear Axle...but not so. I wish they had a diagram of this
tractor and Label all of the Exterior parts so that some of us(me) could identify what is what!!.

Appreciate your rapid response and I'm now much closer to looking at what I need for fluids SAE-90
seems to be the correct fluid.....Ron

Hi Shaun....thank you for your reply.....I will look for that Plug tomorrow to locate it.
Yes my manual does say 6 gallons of SAE-90 weight oil. You say Mineral 90? what type of Oil is that?

Don't worry if you can't find "exact right" lubricants per the original owner's manual. Remember it was written in the 1930's and lubricants have come a long way in the last 80 years.

To that end any "gear lube" viscosity is okay. Whether it's straight SAE90, 80W90, or 85W140.

This is the CaseIH site with diagrams for parts. The names and numbers are there, but parts may be discontinued. Putting a name like Farmall H in the search by model tab works. Jim
Link to Parts diagram

If has been in there 30-40 years you might want to flush it out with some diesel fuel or some thing cheaper, to get all the crude out,and i hope you got a nice warm day to drain it,because that will be about equal too about a 200 weight coming out.

I removed the transmission top cover and used a wood shim to scoop out the heavy thick sludge in the bottom. Glad I did too. Also, be aware when you remove that drain plug the oil is gonna SHOOT out of there. Be ready for that.

I believe there is a second drain plug under the transmission. Check ahead of the drain plug you found for any others to make sure you completely drain it.

Depending on your location you may not want to use the 85-140 for winter use. It can get pretty stiff in cold weather. If up in northern areas I would use the 85-90 or if you want some thing thinner use a synthetic 75-90. The Synthetic will be pricey. I have used it in my semi rearends for the last 17 years with no issues. Running from AZ in summer to Northern MT and ID in winter time. Also in the truck before that in MI year round with no issues there either.
Dad changed the oil in our H 10 years ago when he had it apart for something and just used regular rearend oil 80-90 or something like that. Was not there so don't know for sure what he put in.
You could also use Hytran oil like the newer tractors,just expect to fine seal that might leak from years of use and the thinner oil.

About 20 years ago I bought 2 H's , both 1943 models. I wanted to do the rear end oil changes. I had several surprises and I think you will too ! First, when I cracked the drain plug and opened it slowly I got water running out,one H had about 2 gallons in it the other about a gallon. I got the plug back in quick when oil started coming. I dumped the water and then began draining oil. I left the tractors alone for a few days with a 5 gallon pail under. I replugged and put some diesel fuel in the rear end and drove the tractors around the yard for a while until they were warm,then drained the sludge. I then filled the rears with appropriate gear oil,one with oil from TSC and the other with Coop gear oil. I was happily done with the first tractor and let in sit in my shop. A few days later I noticed some fresh gear oil on the floor. Thinking I slopped some, I wiped it up, next day more gear oil on the floor. Someone on this forum helped me. You see the tractors never leaked oil before because they had already leaked down past the drive shaft seals. When I filled them with the correct amount it leaked out past the seals..so the surprise for you is that you will probably have to replace those seals. It isn't a bad job at all, but if you have a belly pump it has to come out, I had one of each. Once I had replaced the seals there were no more issues

Like was said, likely can be gallon or more water in the case with the oil. Also might have to stick a screwdriver up in the drain to get it going (sludge). Be prepared and have a few 5g buckets ready in case there is more than 7g of oil in there!

Always have way more empty containers for the drained oil than you think you need. I did an M once that was over filled. An M is supposed to have 8 gal. of lube. I drained out 12 gal and there was no water.... Boy was I scurrying to find containers as one filled up. As others have said be ready to change all the seals because she is gonna leak all over.

OTJ

Hi Mike....thank you for your Heads up on the "possible rear end Oil change". I'm not sure that I would
be ready for replacing seals on the rear end, just yet. We are coming into the start of Winter so I may very well
wait until mid summer when its warmer outside. Don't want to tie up the garage for several weeks possibly If
I run into some other issues.

Another question.....those big drain and Fill Lugs are "Square" and I see several of them around the H. Where do you get the Tools that will fit them?? and what are those tools called?? I may have to shop around for a set but don't know what they are called... I appreciate your feed back ....Ron (Maine)

Hi ..and thank you for your feed back on this. With all of the replies that I have been reading
about "changing the Oil in the rear end" sounds like a lot of things could happen in a real hurry!!
I'm not sure what type of "Tool or Socket" is used to loosen that huge "Square Lug". I may have to rethink this project a bit further.....Thank you for heads up.....Ron (Maine)

A cresent wrench should work. Not too hard to change. Go fo it.

Yes....my Service Guide calls for 6 Gals of SAE90 for Transmission and Differential Case.
I best find a few more buckets !!

Agreed. Same thing happened to me except mine was half water. How it ever ran in the winter or didn't crack the housing I'll never know.