SOS cleaning, flushing.

[Btzj02]

I have restored my Dad's 1964 4000 with the SOS transmission. The tractor had been sitting for many years and needed a lot of work. Originally I thought the oil I drained from the SOS transmission looked pretty good. While I was tuning the rebuilt engine, with the traction disengaged, I ran the SOS through each gear and all seemed well. After getting the engine tuned where I liked it I again drained the oil from the SOS and it was filthy. I have refilled with new oil and I have a couple hours driving the tractor around testing all the gears. I do have 10 forward and two reverse gears so all seems to be well but the dirty oil is bothering me. I want to drain the oil again to see what it looks like. If the oil looks clean I will refill and call it good. But, if the oil is dirty again I want to flush and clean the SOS transmission as best I can. First priority is Do No Harm! Does anyone have experience doing this? I have seen many old postings suggesting different fluid combinations to clean transmissions but the SOS transmission has me a little intimidated.

 

[Sean in PA]

I would recommend draining it, filing it with clean fluid, running it for a while, and repeating until it comes out clean. The S-O-S transmissions are pretty particular about what types of fluids that you should, and should not, put into them.

 

[pomester]

I have restored my Dad's 1964 4000 with the SOS transmission. The tractor had been sitting for many years and needed a lot of work. Originally I thought the oil I drained from the SOS transmission looked pretty good. While I was tuning the rebuilt engine, with the traction disengaged, I ran the SOS through each gear and all seemed well. After getting the engine tuned where I liked it I again drained the oil from the SOS and it was filthy. I have refilled with new oil and I have a couple hours driving the tractor around testing all the gears. I do have 10 forward and two reverse gears so all seems to be well but the dirty oil is bothering me. I want to drain the oil again to see what it looks like. If the oil looks clean I will refill and call it good. But, if the oil is dirty again I want to flush and clean the SOS transmission as best I can. First priority is Do No Harm! Does anyone have experience doing this? I have seen many old postings suggesting different fluid combinations to clean transmissions but the SOS transmission has me a little intimidated.

It can get pricy changing oil several times. I have drained the fresh, but dirty, oil into a clean bucket (two buckets is best), and let it set and settle for a few days or longer. Warm temperatures are best. Then pull the clean oil off the top leaving an inch or two in the bottom of the bucket for recycle. A way to do multiple changes economically. Once the drained oil looks good you've done what you can.