Reply to u-joint:
i am not sure what a 40A is. the only good advice i can give you is to get
an operator and service manual. they are a wealth of information on this
subject. i would use cat filters if they are the spin on type. they come
yellow and look cool on the tractor. nothing wrong with cat oils, i use
chevron, but everyone has their faults.
Tugger - The D4 40A is a wide gauge D4C, produced from 1959 to 1963, when it was replaced by the D4D.
The oils you use depend on ambient temperatures. For temperatures above 0°C (32°F) you'd use 30 wt oil or a multigrade such as 15W-40 in the engine.
For temperatures below 0°C use a 20 wt oil or 10W-30 multigrade. The engine oil change period is 250 hrs, and the oil pan holds 3¼ US gallons (12.5 litres) in "early model" tractors, and 3.875 US gallons (14.7 litres) in "later model" tractors. The S/N break for the "later tractor", larger oil pan is 40A3792.
This larger oil pan and increased oil capacity was designed to improve oil supply to the pressure lubricated engine parts, when operating on steep slopes.
The main (flywheel) clutch was a dry clutch as standard .. or the tractor could be fitted with an optional oil main clutch. If the oil clutch is fitted, it takes the same oil as the engine. If the oil clutch drags when trying to engage gears when very cold, you can cut the oil with up to 10% kerosene.
For the transmission and final drives, use 80-90 wt gear oil above 0°C, or 50 wt gear oil below 0°C. This oil has to meet GL-5 specifications, which is an "EP" (extreme pressure) rating.
Originally, GL-5 gear oils had sulphur compounds in them which were detrimental to bronze and brass components of transmissions and gear cases at high temperatures.
Virtually all GL-5 oils are now compatible with bronze and brass. The compatible GL-5 oil will usually have "MT-1" in the API rating, which indicates it's safe to use with bronze and brass, and is designed for non-synchro transmissions.
There are very few components in Cat transmissions and gear cases from WW2 on, anyway, that contain either of these metals.
The EP rating is critical to gear components that have extremely heavy loadings and sliding forces on teeth, such as in hypoid and spiral bevel gears.
The EP rated oils have the necessary additives to resist these huge pressures that would otherwise break down the oil film.
The transmission and bevel gear compartments in the D4 40A are one oil compartment .. it holds 6¾ US gallons (25.6 litres), and should be drained every 1000 hrs. There's no tranny filter on the D4C.
The oil clutch change period is 1000 hrs as well, and it holds 4 US gallons (15.2 litres). Remove and clean the suction screen in the bottom of the clutch at the same time.
The final drives of the wide gauge D4C hold 3 US gallons each (11.4 litres). The oil change period of the final drives is 1000 hrs as well, and when you drain the oils from the finals .. re-install the plugs, then refill them 2/3rds full of diesel, and then drive the tractor back and forth vigorously for 10-15 minutes .. then drain the diesel.
This washes out all the metal filings and tooth chips and prolongs final drive life.
Re the filters .. how good is your aftermarket filter guarantee? Will your aftermarket filter supplier rebuild your engine if their filters fail? Most aftermarket filters are built out of cheaper filter paper, with larger micron filtering ability, barely enough adhesive, and often thinner metal. All to save a couple of dollars!
Use Cat filters, they are not expensive, and they are built to higher standards than many other filters. Use fresh filters, don't purchase old stock or NOS filters off eBay. Filter paper degrades with time, and even Cat won't guarantee a filter that is more than 12 months old (storage time).
The old stock filters, and filters on eBay, can be years old, and you're risking engine destruction for the sake of a few dollars by purchasing old or cheap-rate filters.