Final drive lube question on '42 D4

The oil weights you mention are fine for the engine but transmission and finals use 90wt gear lube minimum.

Oh ok thanks for the help I have a lot to learn about my d4. So another question I have is how hard do you think it would be to locate a rear pto attatchment for my d4?

Here is a scan from the CAT Lube Guide for direct drive tractors.

The 90W weight recommendation is an old recommendation. As the lube technology has changed Cat has released documentation in the form of service grams and new lube guides, outdating many of the previous documents that might have been written back in the 1940's

Cat found out many decades ago especially in areas where there is a high operating temperature and long hours with a heavy pull that the gear oils in the final drives were breaking down and were becoming extremely thin. As a result the bearings would fail then destroying the gears in the final drives.

For a weekend tractor the 90W would probably be fine, if you had this tractor in a fleet that was putting on double shifts clocking a few thousand hours a year you would immediately see that he engineering staff at cat knew their stuff and would see the result of running the Sae 50 oil.

You can run what ever you want but for my old Cats I use the old spec SAE90 in the transmissions and bevel gear compartments. I use Lubrication Engineers 5259 Almagear EP lube in the finals. It is formulated for heavy and/or shock loading and is a SAE250 rating.

Also use straight SAE30 in the engine and ISO 68 (SAE20) in my hydraulic systems.

The lighter oils came later when oil coolers were added and oil cooled brakes and clutches were the norm along with power shift transmissions.

Personnaly I think it is a mistake to run light oils in final drives.

You can run what ever you want but for my old Cats I use the old spec SAE90 in the transmissions and bevel gear compartments. I use Lubrication Engineers 5259 Almagear EP lube in the finals. It is formulated for heavy and/or shock loading and is a SAE250 rating.

Also use straight SAE30 in the engine and ISO 68 (SAE20) in my hydraulic systems.

The lighter oils came later when oil coolers were added and oil cooled brakes and clutches were the norm along with power shift transmissions.

Personnaly I think it is a mistake to run light oils in final drives.

[quote="Old Magnet"]
The lighter oils came later when oil coolers were added and oil cooled brakes and clutches were the norm along with power shift transmissions.

Personnaly I think it is a mistake to run light oils in final drives.[/quote]

You can think whatever you want, but the results of running 50w engine oil in the finals per cat recommendation has made a profound impact on the high hour machines putting 2 -3,000 hrs per year not the back yard toys for the last 40 years like the D4d's, D6c's and D6d that DO NOT have oil coolers on the finals as in the above quote and basically have the same final reduction design dating back to the 1930's.

I don't see those "farm yard toys" as much of a qualifier. I have been dealing with power transmission in heavy manufacturing and materials handling for over 40 years. A couple thousand hours a year is nothing compared to 8000+hrs per year in a 24/7 working environment. As far as Cat and their recommendations my experience is that they recommend just what makes their warranty.