8N Transmission fluid flush

Anonymous-0 · Jul 16, 2011

I'm in the middle of bringing back to life an 8N, serial # 8N370311, and am ready to change the transmission oil, which I can tell has not been changed in a long, long time. Question; should I drain, then "flush" the transmission before refilling with the new 90W mineral oil I have purchased to refill with? And what product should I use to do the flush with?

Brian Jasper co. Ia · Jul 16, 2011

I have used ordinary mineral spirits paint thinner to flush out several transmissions. You of course dont run the engine. I use my 3 gallon bench top parts washer on the floor under the drain and a long piece of hose. Take the top off the trans and you can rinse everything out.

Bruce (VA) · Jul 16, 2011

Are you aware that the transmission, pump & rear end share a common sump? (see tips 3 & 4) You'd be better served by dropping the pump & cleaning it out too. That's were the most sludge accumulates anyway. If you plan to do that, just post back for more info.
50 Tips

Chipster · Jul 16, 2011

Unless you wanna take apart the entire case and the pump to clean it, the best I can recommend is to drain all 3 plugs underneath the rear diff, the pump, and the trans plug. Let these drain into buckets overnight. Then refill with the 90w mineral oil. The flush before I have never tried as far as using paint thinner or mineral spirits. you can however remove the side cover on the pump housing and rinse with the mineral oil. It is best also to drain this after running the tractor including the pto for about 30 mins so that it will stir up sediments and mix then immediately drain.

After refilling with 4.75 gal of mineral oil. Do not put more than that, otherwise the oil will leak through differential onto your brakes and that'd make it slightly difficult to stop!!! Run the tractor for 25-30 hours and then drain again if it's really really dirty. IF it's milkly, look for a source for water to be penetrating the case (ie. the shifter boot, top cover, side covers, etc.) After the second drain and refill, the oil should be in good working order.

Good Luck,
Shaun

JLeus · Jul 17, 2011

A gasket for the pump base to housing is far cheaper than the amount of solvent your talking about. The "goo" I have found in the ones I have done would take days to come lose with thinner, if they would loosen up at all. The vast majority of the mess has been in the section with the pump for me.

8N Transmission fluid flush

Anonymous-0

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Brian Jasper co. Ia

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Bruce (VA)

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Chipster

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JLeus

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