JD 450 Hydraulic oil leaking into engine?

This message is a reply to an archived post by Jim.ME on June 07, 2019 at 11:21:44.
The original subject was Re: JD 450 Hydraulic oil leaking into engine?.

I may have the same problem with my JD450. About
4 gallons of oil came out of my oil change and my
hydraulic oil was down.about 2 gallons. Any
ideas..??

Welcome to the forums.

A bit of housekeeping first. It is best if you start a new post of your own describing your machine and problem. The info in the post you tagged onto doesn't show up and I am not going back to try and find it to see all the conversations, and I doubt that many others will either. I will answer based on what I can surmise from the info here.

If you have a straight 450, does it have power assisted steering? If so, does it have its own pump, gear driven, with a small reservoir supplying the pump with oil? Is that reservoir staying full? That pump shaft seal could put UTHF into the engine.

The main hydraulic system does not tie into the engine, so it is highly unlikely the hydraulic oil is getting into the engine. You may have several small leaks in fittings, hose, cylinders and valves to account for the hydraulic being low. I suspect the diaphragm in the transfer pump is leaking fuel into the engine causing the engine oil level to rise. That is a common failure, and the transfer pump is an easy replacement. Another possibility is the umbrella seals on the injection pump shaft have failed. That is a bit more involved of a repair. Does the engine oil smell strongly of diesel and seem very thin? Those things point to fuel dilution.

Thank you for your questions.
Yes, this is a JD450 with power assist steering. It has a separate small hydraulic oil reservoir above the front of the valve cover that appears to feed a pump on the front of the engine. This reservoir does go down slowly but there are small leaks on the actuators under the seat.

The used engine oil does appear to have a slight diesel smell, and the oil did appear strangely thin. I will pull the transfer pump and see what I can find.

Thank you for your insight.

Sounds like the early model JD400TLB I worked on. It had a separate power steering pump mounted on the engine. The shaft was worn where the seal rides. Parts were NLA so I got a seal and a speedi sleeve for the shaft sealed it up and it worked fine.