Hi all from Australia I'm new to Cat ownership but my dad owned a d6 d7 and a d8 at one time or another when I was a kid . I recently bought a 1954 d4 and found water in the gear box thinking that it may have worked its way down through the gear leaver as the machine had been sitting out in the weather for years. I drained the box than ran the machine for a short while with hydraulic oil in the box then drained it again. Filled her up with nice fresh gear oil and gave it a run a week later. Now the strange thing is when I checked the oil again it is all white and milky again. It has not rained so where could the water be coming from?
I have been loosing water out of the radiator but the water pump does leak a little.
Any ideas becouse I have none.

It seems if I recall there is another plug back in front of the drawbar under the housing too to drain what,s in the pinion & ring gear housing area so maybe you need to remove that plug too. Been lots of years since I worked on one but I believe that could be your water problem yet. The parts book shows two plugs in the housing for draining along with the 3rd. plug under the master clutch.

When you drained the gearbox, did you also drain the ring gear compartment? The plug for this is another hex socket head plug located near the rear end of the housing on the centerline of the transmission between the drains for the clutch/ brake compartment. As the transmission and the ring gear share the same oil (they're connected internally) there might still have been some water/oil mix in there. I would have thought the hydraulic oil flush would have taken care of the water but if the ring gear still had some in it, that's about the only place it could have come from. The only other reason I can think of was the tractor not being level and may have been facing uphill a bit.
The leaky radiator and water pump should have no effect on the transmission.

Thanks looks like I just lost $80 worth of gear oil. The only place I drained the oil from was the the big hex plug in the middle at the back of the machine. I think I really need to get a manual before to long.
This weekend will be the test for the old girl I have to clear about 10 acres of scrub then she can come home. I had to make a deal with the old guy that owned the machine that I would clear his land before I took it away. Its an hour each way from my place to his so getting the old girl running has been a nightmare.

"Betch" wrote:

Filled her up with nice fresh gear oil and gave it a run a week later. Now the strange thing is when I checked the oil again it is all white and milky again. It has not rained so where could the water be coming from?

Any ideas becouse I have none.

you might have 'milky sludge' coating the insides of the gearbox,clinging to the walls of the box.When you drained the box initially,you got the bulk of it but the gearbox still had moisture and sludge which now contaminated the new oil..drain and flush with kero or diesel twice or three times,then refill and run with your gearoil.Sometimes the contaminated lube will turn to paste inside,and it's tough to purge it.Stinks to high heaven too!

I have a D4 2T that had a winch on and water leaked in at the Power Take Off gasket. I know this is not your problem at this momonet but could be a future problem. More importantly while the PTO was open at the rear I tried to flush the sludge out using a small pump sprayer. It worked good on the rear compartment but I discovered that the rear compartment could not be completely drained ( could have been a water source if only drained and refilled). I ended using a rag to absorb the diesel and hoped the forward compartment was not similiar as to thin the 90 weight much. Clay