I've been trying to determine what those hydraulic fit but still can't match that part number.
What I did find is you have to get into D4's to find cylinders with 2" rods. Seems all D5's and 6's used 2-1/2".

Disregard.

Thanks for the help gents. I too have been trying to solve the mystery and have a few more pieces of the puzzle.

First, the stamping on the lift cylinder may not be 2J6380. I cannot make out the last digit all the way, so it is 2J638X. See for yourself. This shot was taken from the top of the cylinder.


The rods are definitely 2", measured the right way with a caliper.

Just to add a little fun, the hydraulic control on this machine is No.163 which doesn't seem right. All the diagrams I have seen say the lift cylinders should operate with No.165 control.



I noticed that the trunnion and eye bearing assembly that attaches to the blade has been welded onto the rods. I think this taken together with everything else is pretty good evidence these cylinders are not original to this machine. Only question for me is where the heck to I find a rebuild kit for the cylinders!

Whoa! Those are high pressure fittings. Good news! Those are reusable ends, the old hoses are hard with age and will likely have to be cut off with a hacksaw or grinder. Make your cut lengthwise with the hose to avoid damaging the insert part of the fitting. All you have to buy is the proper hose.
Craig

Delete.

I am not that up on the hydraulic hose stuff but but some fittings are brand specific as to which hose to use to crimp to. But you are correct this is not a high pressure system. Hopefully some will come forward that have been dealing in hose lately. If your current fitting are the clamshells just reuse. If not I believe Surplus Center in Ne has those fitting listed in their online catalog.

Ok so a couple of things. First, I finally know for sure what the number is on the hydraulic cylinder. The stupid '5' on the end was turned sideways! It's 2J6385 for sure.


Also, I don't think I can reuse the old fittings. Upon taking a few of them out I realized that the clamshells squeezed the fitting so hard that the OD is no longer round, rather quite oval-shaped. I suppose I could turn the clamshells 90° from where they were originally and squeeze it back to round, but I'm a little worried about fatiguing the thin metal. Also someone had replaced one of the hydraulic hoses in the past with the more modern crimp-type hoses so I only have three sets of 'shells.

2J6385 does not appear in my book, often the case with a casting number.

Ok, I will look for another number somewhere to identify the cylinder. If anyone has any suggestions of where or what to look at, I'd appreciate it.
Update: Found a few more numbers on the cylinders, but I'm not sure it really helps. I have spent hours going through online resources and diagrams. The best thing I can come up with is that this is a 3J-2017 / 2018 cylinder assembly, Type 3. There seems to be several 'types', and while they share many parts, there are some that differentiate them. One such part is the 'head' which I found a part number on mine:

I finally found a diagram online which shows this head instead of the expected 2J6371, which belongs to the Type 2 group (this is why I couldn't find it before, Type 3 doesn't appear in my manual!)


The last mystery is why the rod is a 2" diameter.

Do you have a Parker hydraulic store near you? They make hoses at good pricing. I have used them for tractors, havent tried for Cat yet.