Looking for HD11 info

I’m helping a friend get his dozer running. It has set for 3 yrs. He said it was a beast before the trans went out. The trans was rebuilt and put back in and wasn’t touched since. The engine was rebuilt prior to the friend buying it. It’s in awesome shape. I’m trying to figure out the year and other info I can get. I have some free pdf files of different HD parts manuals, I would love to get ahold of the service manual for that model. I know the engine is a 11000, I would like to know what the other numbers mean. I have pics of the engine serial plate. The dash plate is gone but I have a pic of the serial number stamped on the rear. The engine plate numbers are, engine model 11000, engine serial 11-17337. Now for the dozer serial, it doesn’t look like anything anyone else has posted. It’s stamped HD11 305. My main concern for right now is what fluid to put in the transmission. I’ve read two different things, one said use 10wt and one said 80-90w would work. Which would be best? I want to do it right the first time. I already assume 80-90w goes in the bevel gear area.
Notice the six on the far right of the dozer serial number. It’s bigger and a different style of stamp. Looks like someone took a grinder to it to read the numbers or something. I don’t think it’s deep enough to take off numbers though.
If I could just get a little help with a service manual and what oils to use, should have it up and going in a few days.

Just remembered. I also am looking for a fitting for the return line that connects to the fuel tank. Fitting was lost. The male fitting on the fuel tank itself looks to be 3/8. I tried a couple different 3/8 fittings and they wouldn’t screw on and I didn’t want to force it. The parts manual say

I’ll get more pics of the dozer and post them later. Thank you all in advance for your help.

I have been around a number of HD 5's,6's,and 9's.All the same design as the HD 11 was only a engine update from a HD 9. All had gear oil in transmission at least as far as I knew. That's what my dad and uncle gave me to put in if needed. Also have a herd of Cat D6's I mess with today,same vintage as the AC's. I know Cat updated and recommended 30 or 50 weight oils in the 70's,but rescinded that and went back to saying heavier gear oil was OK.

If the transmission is standar shift you need 80/90 gear and final drive too and power shift transmission use 10wt oil.

Someone definetly took a grinder to the rear housing to grind away the serial numbers. Its a early HD11B prior to serial number 6069. That has had a late 11000 engine fitted to it.

Looked up my old book for one a mate had HD11B 1351  which is what yours is close to

Thanks for the replies. Dozer will start will a couple shots of starting fluid, but won’t start on its own. Opened up all the lines on the injectors and not getting any fuel to come out. We took off the top cap of the pump and it’s full of fuel. Any suggestions? Thanks gemdozer I’ll send you an email and we can work out details.

Tank is half full or more and valve is open. We have good flow of fuel up to the pump, just nothing out of it. We are getting power to the wire on the top cap. Just a thought. The first time I had the cap off I was looking at the parts inside, and the mechanism that is down and to the side of the throttle spring. It looks like it’s supposed to move so I tried to move it and it didn’t move, didn’t think about it either, figured it moved with the solenoid. I put it back together, we messed with it a while longer and got nothing out of it. So I said screw it and took the pump off, thinking it needs rebuilt. I took the top cap off again and was studying that mechanism again and figured out that solenoid lines up with that which would be part of the engine kill? Correct? So I then budged that thing with the tip of a screw driver it was stuck a tiny bit. I didn’t have to put much pressure on it. Now it moves freely by finger. So I put 2 and 2 together that is part of the fuel shut off that is kicked off by that solenoid. So now that i think I wasted all that time taking off the pump, all I had to do was break that free. I went to put the pump back on the shaft I noticed one of the little umbrella gaskets looks a little rough. I guess that’s where I’m at now, ordering shaft seals.

Re tranny oil: mine is direct drive 6 forward and 6 reverse H/L I use TO4 10W

thanks dozerd I was told by previous owner to use to4 10w might try your specs because the to4 10w seems to leak out quickly