type of oil to use in transmission

hi all im new to the group and am just chasing some information, i dont axually have a cat crawler mine is a case 1000 but i cannot really find any information on it as it is so old i am trying to find out what oil i should use in the transmission as it needs repalcing it is a 1950's model and has a torque converter and hydrallic lines into the transmission housing would it be like tractors of the time and use a gear oil rather than a thinner hydrallic oil is my question any help on this matter would be apreciated.
regards joel.

I'm not sure when the model 1000 came out but if it's like the 1964 literature I have they used or recommended the Case TCH non-foaming all weather use oil.....TCH being Transmission/Converter/Hydraulic all in one designation....or modern equivalent.

I am not sure if they still make the TCH. Now they say to use that if you lived in a colder area. But the replacement is Case Hy-Trans Ultra. I need to get some of that for my Case 680G backhoe.

John

thanks for the fast reply guys it is around the 1955 i believe. ill look into both those oils 👍

from the CAT D2 owner and operation manual:

"Transmission Oil (TO) use MIL-L-2105 spec oil or straight mineral oil. Use either oil conforming to the requirements of MIL-L-2105 specification (you can find that on the web, I'm sure) or straight mineral oil whichever is most convenient.

At temps above freezing use SAE no. 90 oil, but when operation continuously in extremely hot temps, use SAE 140. Below freezing SAE no. 80 oil will be required however, in extremely cold weather SAE no. 80 oil should be diluted with sufficient kerosene to provide fluidity"

That is the 90 and 140 weight gear oils I've always known. I'm off to buy some now as my trans had lots of water in it while sitting uncovered.