New D2 5U owner oil leak on rear sprocket

Ahhhh, welcome! I think I saw that gem offered for sale recently. I had to use all of my willpower to keep from adding another one here.(no room at the inn ha!) Sounds like it gets a good home and will get its pads shined up a little.
Your question regarding the leak: many will lose some lube from sitting a long time/lack of use; I have had some thrifty folks pump some track lube (00 semi fluid grease) into the leaking side along with the gear oil, and it seems to help. Not a proper fix, but a good temporary solution that does not require a lot of $ or tear down of the tractor. The lube will solidify when cooled down and likely not ooze out like regular gear oil.
Share your location please, and a little more about yourselves! You might just get invited to a BBQ nearby! JM

Thanks Juiceman! Yeah I definitely dont want to tear down the tractor $$ just to fix the leak if theres another solution. Thats a nifty trick with adding some thick grease and oil to help slow down the leak. My main concern is just having all that gear oil leak into the ground as the tractor shed is near a garden and our well. Just started going through the D2 this weekend, need to get her cleaned up, replace the fluids and filters and I also am thinking of rebuilding the pony motor carb. 

I live in San Jose, we are on just over 5 acres in the hills north east of San Jose and love it up here. This D2 is our 3rd tractor, we also have a newer kubota 4x4 and a 1950 John Deere MC crawler that I love but its just a little under powered to pull our disc, which is why we got this D2. Ive been in love with tractors and farm equipment my whole life, my 2 year old sons first word was "tractor" haha and when ever he saw a truck or tractor he would point at it and say "dadda". Since you saw the D2 for sale are you local to the bay area? -Steven

 

Thanks Juiceman! Yeah I definitely dont want to tear down the tractor $$ just to fix the leak if theres another solution. Thats a nifty trick with adding some thick grease and oil to help slow down the leak. My main concern is just having all that gear oil leak into the ground as the tractor shed is near a garden and our well. Just started going through the D2 this weekend, need to get her cleaned up, replace the fluids and filters and I also am thinking of rebuilding the pony motor carb. 

I live in San Jose, we are on just over 5 acres in the hills north east of San Jose and love it up here. This D2 is our 3rd tractor, we also have a newer kubota 4x4 and a 1950 John Deere MC crawler that I love but its just a little under powered to pull our disc, which is why we got this D2. Ive been in love with tractors and farm equipment my whole life, my 2 year old sons first word was "tractor" haha and when ever he saw a truck or tractor he would point at it and say "dadda". Since you saw the D2 for sale are you local to the bay area? -Steven

 

Check and see if the oil is leaching out from splines under the big nut holding on the sprocket. Looking at your picture it appears the whole sprocket is black. If it is the bellow seal oil would be running down the case behind the sprocket.
May need to put some sealant under the big nut.
Check it out and report back.

Side-Seat, thanks, Im pretty sure it's leaking just behind the nut on the spline. I was just looking at the parts manual for the tractor and I see theres a gasket just behind the nut, that makes me feel a bit better, hoping it's just that gasket that is leaking which should be an easy fix. Will take a look later this evening and will report back. 

@Juiceman, would love to come to the next BBQ

keep a eye on it. if its a slow leak like our d4 just keep topping it up. with some fresh oil and some use it might slow up.

we were told sometimes if the bearings need adjustment it will weep from the bellows seal and nipping the up can slow it down even fix it. to check for play jack that side up so there is no weight on the sprocket and use a pry bar lever on it to check the play. the destructions are in the servicemans book. the c hook spanner to adjust the bearing aint cheap so we just keep topping ours up.

Check the sprocket for tightness on the shaft. If the sprocket is loose on the shaft it will need to be pressed back on the shaft. You will need special tooling to press it back on if it is loose. I think it takes about 12 to15 tons of pressure.

Your tail seat will be right at home there. There used to be dryland apricot orchards up in those hills. Your Cat must have lived on an irrigated orchard on the flats because it has check breakers.

I bought the D2 from off a farm down in Hollister where it lived for 12 years. It still has a sticker from Holt of Stockton so guessing it was purchased there and worked the old orchards in Santa Clara valley. The seller said it spent most of its life in Coyote Valley in south San Jose and was owned by the IBM corporation at one point which has an old campus in Coyote Valley.