Should I use a flushing agent for changing transmission oil

[RedRover 27]

An earlier posting indicated using a flushing agent while changing transmission oil for my recently acquired 312-8.  Indications are this tractor may have been exposed to the elements somewhere along the way.  Dipstick shows cloudy and lots of rust above the fluid level on the dipstick.  Comments such as type, brand and even methods are welcomed.

 

This 312-8 will be my 3rd on hand.  First one purchased new in 1988.  The 2nd one had been used but was in perfect condition with no issues.  This one is going to be a challenge to get it up to par.

[WHX?? 49,177]

Many of the guys here use plain diesel for flushing. Kerosene works as well. Drain all the old oil out first. It helps to safely raise the front of the tractor to get the cup or so of oil out in front of the casing hump. Run the tractor if possible or try and slosh it around. Drain noting the appearance of what comes out. This may have to be repeated several times. Doesn't hurt to overfill abit at this point. Once you get most of the crud out refill to dip stick  full with a quality 80/90 wt gear oil. If this is a working tractor change the oil at least once a year.  Check the boot on the shift lever as that's where water usually gets in.   Good luck with your  and don't be afraid to ask with any issues.

Edited March 15, 2018 by WHX14

[953 nut 55,837]

            Jim @WHX14 has just given you a perfect text book answer!  Any other questions feel free to ask.   

[stevasaurus 22,872]

Jim pretty much covered the process.  I would just add, if the horse runs, I would run it in 3rd gear for about 15 minutes and also in reverse for another 5 or 10 minutes.  I would also run the horse on blocks.  Sometimes, those old oil seals will leak a little with the thinner diesel or kerosene...you don't want that in your grass.  It will take about 2 qts of fresh oil to re-fill. 

 

Welcome to Red Square 

[Tankman 3,518]

Jim gave you the answers, excellent.

 

Years ago I delivered gear lube to UPS truck repair facilities. Their data base (thousands of trucks) proved to them

Mobil 1 80w90 synthetic gear lube extended gear life, worth the added expensive.

 

One racer I knew was getting one (that's 1, one) race per rear.

Using Mobil 1 synthetic 80w90 gear lube his lasted for three (that's a big 3) races.

[RedRover 27]

Thanks to all for the good direction concerning flushing gear transmission box and using 80-90 Gear Oil for refill.

[pfrederi 17,887]

13 hours ago, Tankman said:

Jim gave you the answers, excellent.

 

Years ago I delivered gear lube to UPS truck repair facilities. Their data base (thousands of trucks) proved to them

Mobil 1 80w90 synthetic gear lube extended gear life, worth the added expensive.

 

One racer I knew was getting one (that's 1, one) race per rear.

Using Mobil 1 synthetic 80w90 gear lube his lasted for three (that's a big 3) races.

 

 

Certainly nothing wrong with Synthetic but UPS runs their trucks 8-10 hours per day every day and they are worked hard. Our Horses are not worked nearly that hard and the biggest gear oil issue I see is water getting in either through a bad rubber boot or just condensation. I would rather spend the extra money on changing regular dead dinosaur oil more often.

[Tankman 3,518]

1 hour ago, pfrederi said:

 

 

Certainly nothing wrong with Synthetic but UPS runs their trucks 8-10 hours per day every day and they are worked hard. Our Horses are not worked nearly that hard and the biggest gear oil issue I see is water getting in either through a bad rubber boot or just condensation. I would rather spend the extra money on changing regular dead dinosaur oil more often.

Exactly correct. I might spend the $$$ on my pickup but, on my Horses "not".

Changing the shift boot if cracks are seen is always one of my PM's (preventative maintenance) chores. A new shift boot is rather inexpensive also.

 

I share my opinion with pfrederi. 

[ohiofarmer 3,276]

I Jack the front end up by lifting the tractor very high with a chain hoist. Then take a clear vinyl tube and snap it on the vent nipple on a gasoline fill can. Now take a shop vac and put suction on the fuel spout and take the free end of the vinyl tube and suck out as much as you can from the transmission drain.. It is pretty cool that the grundge stays in the fill can and does not make it into the shop vac

 

 Now get serious about the glop that lives at the bottom of the gear case. Use an engine cleaning gun and fog that case with atomized Diesel through the filler tube. The old sludge that it removes will surprise you. When the Diesel starts looking clear, you may want to stop sucking it out and just add some more and let the tractor down and let it soak overnight. My transmission case had no filler tube extension and that made it easier to distribute the Diesel through the transmission case.

 

 Try it--it works well without wasting a lot of fluid

[RedRover 27]

Thanks to all the responses and good methods of flushing etc.  All sound like good methods and some, pretty elaborate procedures.  I am not set up for the more elaborate methods.  I did raise the 312-8 up, especially the right side front because it appears that was the best way to get the most drainage.  After flushing twice I used a very old anti-freeze tester with the large suction bulb.  The receiving tube worked perfectly while inserted into the bottom of the transmission gear box.  (I wonder how many of these old 1950s era antifreeze testers are still around)