JD300 transmission filter guts missing

MAYTAG MAN · Nov 14, 2011

I own a 1972 John Deere JD300 backhoe/loader that is in pretty good condition BUT I found the transmission oil filter missing in the canister. The canister has a threaded rod and no pressure relief housing and the seal blew out with oil going everywhere. Any suggestions? Where to get such an animal. The canister is still good but I hate running it with no filter. Apparently the canister blew out due to cold weather icing and something happened to the guts.

:confused2::drool:

oldnslo · Nov 15, 2011

My guess would be some body removed the guts since they usually have some metal in the caps.

JD would still have elements.

Roy

jonyyuma · Nov 15, 2011

MAYTAG MAN said:
I own a 1972 John Deere JD300 backhoe/loader that is in pretty good condition BUT I found the transmission oil filter missing in the canister. The canister has a threaded rod and no pressure relief housing and the seal blew out with oil going everywhere. Any suggestions? Where to get such an animal. The canister is still good but I hate running it with no filter. Apparently the canister blew out due to cold weather icing and something happened to the guts.:confused2::drool:

Most likely the previous owner encountered some stoppage and removed it for quick action. then he forgot about buying a new one. JD and several others will still sell you a hydr.filter. My best would be sure of it and get it from the dealer the first time for proper fit? Your new one might plug up early due to doing its job and removing foreign objects?

MAYTAG MAN · Nov 15, 2011

Thanks jonyyuma. My question still remains. Why does it have a threaded rod instead of an oem bolt and why is the spring and plate at the bottom of the rod missing as well. Oh and now I discover the accumulator is not hooked up and the block where the accumulator is supposed to be attached is plugged with some kind of bolt instead of the 90 degree fitting. It is indeed an open center system. And now the jackpot question. Where would I ever get the spring and the plate that the filter is supposed to rest upon? I guess I will have to go to my machine shop buddy and have him make one. Wow, I hold my breath anticipating someone has one of these filter gismoz kicking around somewhere between Maine and Oregon. I DO HAVE THE FILTER CANISTER THOUGH. Can I make something work?

MAYTAG MAN · Nov 15, 2011

I have removed the transmission and backhoe filter canisters and drained the backhoe filter housing and the two drains on the transmission (each is 1 1/4''). I am prepared to rebuild the accumulator if I can reattach the 90 elbow to the block. Is it a good idea to flush the transmission sump area with a small amount of gasoline and let it dry completely? I would also like to take the reservoir off and clean that out real good. Anywhere else crap might be lurking?

J_J · Nov 15, 2011

Is there any reason that you can not get a new filter housing and new filter?

How about some pictures?

MAYTAG MAN · Nov 15, 2011

Hi JJ, the upper part of the transmission filter seems to be a part of the transmission and the lower part is detachable. I am doing the research to see if it is available either as a new part or as a recycled part. I would assume that it is not a part that would ever really wear out unless the spring lost it's tension. I am hoping that if JD doesn't have one, someone else will.

mmurphy · Nov 16, 2011

MAYTAG MAN said:
It is indeed an open center system.

Unless some one removed the radial pump, and replaced it with something else, it is a closed center system.

MAYTAG MAN · Nov 16, 2011

I found the number on the bottom of the filter canister and actually found many used filter canisters with the rod, spring, plate, and circlip on the internet. Ended up purchasing one from Wengers of Myerstown for $75 including shipping.

I wonder if leaving the filter out was an attempt to speed up the tractor. I think the threaded rod and the absence of the guts leads me to believe the original bolt broke because of the cold weather and too heavy oil and moisture freezing causing the pressure to break the bolt. The filter was then left out in an attempt to prevent that from happening again.

What is the major difference between an open center system and a closed center system. My book shows an open center system main pump having an external adjustment screw on the top towards the radiator and the accumulator is set up in a hydraulic distribution block. The closed center system shows the accumulator in the hi pressure line from the pump to the backhoe as well as to the power steering valve. Did I just answer my own question?

J_J · Nov 16, 2011

If you have both hyd system, they must be separate.

The open center hyd system, is always pumping, and must use open center valves in the flow path. The pump is usually a gear pump.

Closed center system usually has a variable speed, or constant speed pump and only pumps as necessary for a cyl or hyd motor tp operate. T

Hydraulics:
Type: open center
Capacity: 16 gal [60.6 L]
Pressure: 2700 psi [186.2 bar]
Total flow: 24 gpm [90.8 lpm]

Some people say that your JD is closed center. I refer you to post #19

http://www.tractorbynet.com/forums/hydraulics/124893-john-deere-300-industrial-hydraulic-2.html