Good Morning from snowy southern new mexico. We just aquired what I beleive to be a 1950-1957 D4 7U, just needed some batteries and she runs great. We have used it alot to do mesquite and brush control on a cattle ranch and want to make sure it continues to run well. So far I have greased all the buttons and zerks and made sure radiator fluid was good. My only concern at the moment is the large plug right above the clutch shifter, I cant get open (yet) but I would assume thats clutch and final drive lube? If so, what kind do I need to use? Also has anyone ever rebuilt the distribution box that the hydraulic fluid is transferred too.. It leaks pretty good. This is pretty much our best piece of equipment and would like to keep it running. Also if anyone knows where I can get a service manual, thanks!

Brian Samson
Ranch Manager
NMSU

Hello Brian,
If this tractor has an oil clutch then there should be a dipstick somewhere close to the firewall. Transmission may have a dipstick near the gear shift or a check plug on the side of the transmission case. Final drive oil is checked on the lower rear end of the tractor near the drawbar. There will be two plugs back there that require a hex shape wrench to open. You can make one by welding the right size nut on a steel bar.
Start shopping on Ebay for manuals, you should be able to find them there. Operators manual and parts manual are the two most useful for getting started.
If you could post some pictures that would be good.

Also tell us the serial number if you can find it on the rear end of the tractor.

Here is the "Capacities" page from the Operation and Maintenace Instructions manual for the 7U/ 6U D4 (form 12244-7)

Thank you guys so much, I will get a serial number sometime this morning when the snow stops, And yes there are 2 dipsticks one by the shifter and another closer to the firewall as well as the oil dipstick closer to the front in the motor. and I found the final drive tanks the other day and filled them up with 80#

get some kerosene or diesel in with that 80 weight, should be 30 weight. operators manual is the most important manual u can get now. i got 1 4 $20.00, but post ur serial number first. u series d4's started in 1947. u might not even have a u series machine. good luck.

If I understand you, you put the 80 weight in the final drives. That is correct. There are two more gear compartments, the transmission and bevel gear compartment (would be the differential gears if a dozen had a diff) which is just behind the trans and the oil fills both compartments. I believe there are two separate drain plugs to take out if you need to drain it.

i thought theres been discussion about 80 wt. being to thick to get rotated effectively to the top of the final case to lube the pinion bearings, especially in cold weather. i also think there was some service bullitan about using lighter oil there. anyway i use lighter oil in my finals all the time but my tractors don't get used much.. but as always and most of the time i could be wrong. thanks.

SAE 90wt gear oil is correct for above freezing temp.
SAE 80wt or less for below freezing.
SAE 140wt for extremely high temps.

I have run as high as SAE 250wt in applications where shock loading is severe.

At one time (in the '70's??) CAT was at least allowing the option if not recommending 30 wt oil in everything, probably in the interest of simplicity of servicing multiple machines in fleets etc. However, that is no longer the case. The gear loading is just too high in the final drives for sure and probably the transmission/bevel gear compartment as well.

I have run 50 wt Delo 100 in the transmission of our 9U for quite a while now, mainly because I had a barrel of it sitting around when I drained the old contaminated oil out several years ago. I think the correct recommendation is for a gear lube though, not a motor oil.

The finals have a multiweight 85-140 mineral oil based gear lube.

The remaining compartments on the clutch of your tractor, the injection pump housing, the air filter oil cup and the diesel engine crankcase all use a 30 or 40 weight oil for most temperatures above freezing.

Changing oils on one of these beasts is not a minor expense, though it certainly is cheaper than replacing parts!

"ranchmanager2012" wrote:

Thank you guys so much, I will get a serial number sometime this morning when the snow stops, And yes there are 2 dipsticks one by the shifter and another closer to the firewall as well as the oil dipstick closer to the front in the motor. and I found the final drive tanks the other day and filled them up with 80#

Ok, here is the serial # of my D4: 7U42593. There are the 2 oil fill caps on the floor of the operators cab. One by the shifter and one by closer by the "firewall" as well as to 2 in the back by the drawbar on each side. Can someone please tell me what and how much I need to put in each of the 3? also if anyone has a service manual for my year I need to buy one, thanks!