[Chuck79]

Hi All. I picked up a JD400, late 60's early 70's I'm guessing. I changed the hyraulic fluid, main and return filters. I cleaned the large tube screen which was covered with a white paste. The old oil was also milky. Back together and running fine but I seem to be having one or a couple of hydraulic issues. When I try to lift the loader there's a long pause then chattering then it starts to go up but weak and chatters most of the way up. I also hear a whining sound coming from the bottom of the steering. From the couple of threads I've read I'm thinking these could be related. If there was a leak in the steering would that drain the reserve tank on top of the cooler? When I've pulled the cap on the reserve tank it always seems to be way down. Can the steering be isolated from the pump to see it that solves the issue? Any help would be greatly appreciated. Thanks Chuck

 

[Tx Jim]

Welcome to GTT
JD 400 below serial # 045,199 had open center power steering powered by pump mounted on RH frt of engine. Above listed serial # had closed center power steering that can be isolated by removing supply line then capping line so hyd's can be tested. Does this 400 have a rockshaft/3 pt or BH? I suggest you acquire a JD tech manual for model 400 because closed center hyd's repair requires ""good diagnostic procedures"" not merely replacing parts.

 

[Chuck79]

Hi Jim. Thanks. Yes I have the manual. I'm looking through Amazon for a set of gauges to test the hydraulics. My machine has a backhoe. I'm checking the relief valves today like the manual says. I'll then move on to the gauges. It seems to be a problem with the oil getting to the main pump. Thanks again Chuck

 

[Tx Jim]

Your Welcome
My knowledge of JD industrial equipment is limited due to my being employed at an Ag only JD dealership. I served as a JD dealer service manager for 13 yrs of my 21 yrs of employment at dealership. 1st thing you need to check is trans pump gpm supply to frt pump.

 

[Chuck79]

Thanks. Will do. Do you know the range it should be in? Also any suggestion on gauges? I see lots on Amazon and a big price difference between them. I figure I'll use the maybe twice in my whole life so the most economical without falling apart would be ideal. Thanks

 

[Zebrafive]

You will need two pressure gauges. One 0-300psi range and another 0-3000psi range. Then hoses and adapters. It might pay to buy a kit that contains everything. I will ASSUME a tractor from the '60s will not need Metric adapters.

 

[Chuck79]

You will need two pressure gauges. One 0-300psi range and another 0-3000psi range. Then hoses and adapters. It might pay to buy a kit that contains everything. I will ASSUME a tractor from the '60s will not need Metric adapters.

Perfect. Thanks. Yes I would assume no metric stuff

 

[joerauh]

Not sure to open a new discussion, or just ask a question:
I also have and old JD400 serial number T5W3D 057511T. I screwed the hydraulic system by adding an additive to stop leaks. So I will drain it all, and clean the filters. Question, I have the manual, but a bit dense.
1) Are there three filters to check? two in the transmission and one in the pump?
2) Hydraulic oil to use. I know I can find something at the Deere dealership but was hoping for a more frugal solution. Does tractor Supply or places like that have decent oil for the JD400?
3) How much should I get? 15, 20 gallons?
Thanks, Joe

 

[flyweight]

Joe,
The filters are located below.
Oil capacity is about 11 gl.

Small pump(0.69 & 1.38 ci).
Filter(54) is in the pump body.

Large 3.0ci pump.
Filter(17) is in the pump head.

Main hydraulic/transmission filter(2) is mounted under the transmission case.

Depending on how the tractor is equipped, there mat be a filter(19) under the right floorboard, mounter to the side of the transmission case.

 

[joerauh]

Thank you much, looks like I have the high volume pump. Was able to pull the screen when on the tractor. It was clean, but with small ttear, so I am replacing that. Found out I had to remove (or slide out of the way) the secondary oil filter to get the main transmission screen out. That screen was really dirty. Replacing the pump screen and tranny screen, and both filters which look the same. Found a crinked line, so I'll try to replace that as well as some worn hoses. Thank you for your help.

 

[joerauh]

Well, still have a very slow hydraulic system, and no mechanic within reasonable miles so I have invested in pressure gauges, and a series of swivel run tees which I hope to get next week. I'll go down the manual's list of troubleshooting. If anyone has words of wisdom, please lay them on me. My front loader is as slow as my backhoe hydraulics, so the pump will be my first test.
I did find out why they made the oil filter gaskets bigger than I expected. You need to put the gasket in the tranny first then install the filter. (7 gallons of precious hydraulic fluid wasted). Thank you all for your help.

 

[Zebrafive]

I've been there with the transmission filter. I had the leak, really sprayed the oil, twice in row. I just caught it quicker, and lost a lot less oil.
First time I put the "gasket, square O-ring" on wrong. The second time it must have dropped a little and got pinched. Third time was charm.