Wash system with diesel fuel?

[Orangegroveguy]

Greetings all: This coming Monday, I will be changing the fluid/oil in my new to me Deutz 6806 tractor, (made in 1975). Previous owner filled the system with 80W90 GL-5 gear oil. He ran it that way for about five years before it came my way. I have discovered 80W90 is the wrong gear oil for this tractor. Today, I picked up ten gallons of Universal Trans-hydraulic fluid from Rural King, (35 dollars for a five gallon can) and ten gallons of Cam2 303 oil, (19 dollars for a five gallon can). My plan was to drain the system, replace the filter, then do a "wash" with the 303 oil in order to get as much of the 80W90 out of the system. After several hours light run time, I had planned to drain the 303 oil and replace it with the Hy-tran fluid. I've read of several tractor owners cleaning their transmission/hydraulic system with diesel fuel. Can I do that with this system? I has a dry clutch, but the power steering system draws it's fluid from the transmission. I want to clean this system out as good as I can in order to get as much of the 80W90 out as possible. From what I have read, if cleaning with diesel, the transmission is filled with diesel, the motor is started and the gears are allowed to turn but the tractor is not drive nor put under load of any kind. Once the tractor has been run, it is then shut down and the diesel is drained and replaced with the proper fluid. Is that possible with this tractor or is it more trouble than it's worth. Thanks in advance for any guidance, wisdom and insight - Glenn.

 

[CincyFlyer]

Some older tractors would have gear oil in the rear axle if it wasn't integrated into the transmission/hydraulic system, and my new tractor uses gear oil in the front axle (4WD). I'm unfamiliar with the Deutz. If it's just the rear axle or transaxle, I'd bet you'd have no issues with the "wrong" oil. If he had 80W90 in the hydraulic system-now that would be odd, I'd be surprised if it operated correctly, and I'd get it out of there stat.
BTW, in the olden days, we'd clean out sludgy car engines by running them with kerosene in the crankcase! Not under any load. Tons of goo could be drained.

 

[Orangegroveguy]

I remember those days and have done it myself, using both kerosene and #2 diesel fuel. As far as the Deutz is concerned, the previous owner bought the tractor used and used it to maintain a five acre parcel he owned. When he purchased the tractor, he felt the "maintence mood" and decided to change the fluid in the rear end thinking what was in it was probably the factory fill. Assuming it was merely the rear-end, he drained it and filled it with 80W90 GL 5 gear oil. What he didn't realize at the time was the power steering pump draws fluid from the rear end. When I bought it from him, he swore it had no issues, (other than looking rusty and beat up). It fired right up and ran well, but was hard to steer at first. Long story short, I lost steering on the way home, (about a two mile drive). When I finally got it home and started working on it, that's when I discovered he had used 80W90. Research has revealed hy-trans should be used. What he thought was "water in the fluid" turned out to be "air entrainment" due to a leak in the seal on the front hydraulic cylinder. Keep in mind, all this is new to me as well as I've always done my tractor work with an old Case model "D" tractor, but I'm learning step by step. I'm looking forward to Monday's drain and fill adventure.

 

[Dave M7040]

My experience with the "cleaning out," you want to do had a bad outcome. The loosened sludge did not just drain out the drain plug but blocked small hydraulic passages and, in the end, ruined the machine.

I would exercise caution because the benefits from removing sludge than has sat quietly for decades without causing problems, are not worth it.

if it is that big a deal for you, then take it apart and physically remove it.

Dave M7040

 

[Orangegroveguy]

Excellent point Dave. I hadn't thought of it, but this past Tuesday, I removed the hydraulic filter that lives beneath the seat. What I noticed when I removed the filter was some black gunk around the base of the filter which I assumed had built up there over the years. Keep in mind, this is inside the transmission. To remove this filter, you unbolt a little cap, remove the cap and then pull out the filter. If this tablespoons worth of gunk was at the top of the transmission, I shutter to imagine what might be at the bottom. Thanks for the heads up.