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312-8 Uni-Drive Trans.

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I have a 312-8 tractor with the Uni-Drive Trans. I believe the tractor was made in 1989. The tractor had been sitting for many years and upon draining the the tranny I noticed the oil was sort of a tan milky color. I take this is due to water from condensation. So my ?'s are should I flush the tranny with something say like some cheap SAE 30 oil? Also with that tranny I have do I refill it with SAE 90 oil or something different, and how much oil do those transmissions hold?

:hide:

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The thread that dennist mentioned has a lot of good advice, I'll just add a few of my own thoughts.

If your tractor has been sitting outside for any period of time, there's a good chance it's picked up some rainwater through a defective shift lever boot -- make sure you check that, and make a note to replace it if necessary before you're all done with this project. It's also a good time to tighten the lever if it seems loose -- it's not hard to do, just make sure you don't drop anything inside the trans. through that opening. :hide:

I use kerosene to flush my trans., mostly because I usually have some around the shed. Others will recommend ATF or diesel or engine oil. I don't think it matters much as long as you're only using it for a short period of time to flush out the old fluid. The important thing is to run it through all the gears, including reverse, either while the tractor's up on jacks (be careful!) or out in your yard, maybe 15-30 minutes total. Then drain it, repeat the process if you think it's necessary, and fill with proper gear oil.

The nominal capacity of these units is 2 quarts, you should be able to get close to that when you drain out the old fluid. I usually start with 1-1/2 quarts to refill, and then top it up as necessary to get to the full line on the dipstick.

A couple of other things you might consider doing while you're back at that end of the tractor: check for leaks, check for axle play and tighten your wheel hubs. There's threads here that discuss all these things.

Here's another link that goes into more detail on some of these issues, there's several other good ones on rebuilding your trans. if it ever becomes necessary:

http://www.wheelhorseforum.com/index.php?showtopic=26541

--------

By the way, do you have manuals for your machine? There's owner's and service manuals for both your tractor and your engine, just ask if you don't have them, they're really useful. There's also a complete transmission service manual if you need it at some point.

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Thanks for the replies guys, the threads you posted were very helpful also. I'll mention that the tractor only has 35 hours and is like brand new. I got the tractor from a guy who inherited it from his mother in law who didn't use after her husband died, and he didn't have a use for it, so I bought from him. For the most part this tractor has just sat around in garage for all this time. I used it last winter to plow snow and it worked great.

With the tranny oil I drained out being milky and reading the other threads posted I will split the tranny apart and see how bad it is and clean it then put back together. I haven't any leaks so I' sure the seals are good. Doing the flushing thing I could see where not all of the bad fluid would get out, even if you're getting clean fluid when you drain the flush solution.

Do you guys have a good source I can go online to to get tranny parts from? Seals, gaskets, and rubber boot. Thanks Again! :hide:

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Do you guys have a good source I can go online to to get tranny parts from? Seals, gaskets, and rubber boot. Thanks Again! :WRS:

I always think its a good idea to keep your local Toro dealer in business. :hide:

The shifter boot and gasket are Toro parts, should be around $5 apiece. Seals are available through Napa and the bearing houses, although lately I've been buying them from my Toro dealer as well (check his prices first). If you do need to replace bearings, the needle rollers are a lot cheaper through a bearing house. There are threads here giving you the numbers.

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I fully agree with doing business locally and helping them to stay in business. My problem is that I live in Alaska and there isn't of any Toro dealerships around.

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Just my two cents, but if the tranny oil was milky and not rusty, was kept under cover, and the machine has only 35 hours on it and no leaks, I wouldn't bother splitting the tranny. I'd flush it with diesel or kero like the guys suggested, and be sure to drain it using the plug on the bottom of the tranny so you get everything out. Generally if there's any amount of rust to be worried about, it will show up in the old tranny oil or more likely in the first flush with diesel/kero. If you see rust in those fluids, then maybe a tear down is in order. The milky effect may just be a little water that snuck in around the shifter boot while it was warm and you were plowing snow - doesn't take much to show up in the oil.

It certainly wouldn't hurt to do a tear-down, but if not necessary and you need the tractor to mow with or some such, why invest the time? :WRS:

Duff :hide:

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I almost replied when I read your post last night, but I'm with Duff on this one. These transmissions are really strong and will last a huge amount of time before they NEED to be split apart.

Does the trans. work well in all gears, with no unusual noises or problems? With as few hours as this machine has, if everything seems OK, I would just do the drain/flush/refill thing, tighten the shift lever if necessary (probably not), certainly replace the shifter boot if it's bad, and then just drive and observe.

That's my 2 cents, and worth every penny! :hide:

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I agree with you guys in that with the small amount of hours the tractor has, flushing the tranny as recommended will do the trick. I was thinking with the tractor sitting around as long as it has there might be oil and goo cake inside the case and would be hard to flush out. I'll try flushng it out a couple times and see if comes out clear and if it doesn't and comes out rusty then I'll split the tranny. I'll replace the rubber boot for sure. I don't use the tractor hardly at all now for my yard is way to big for it, and I have a bigger one, so I'm thinking of selling it so I have more room in my garage for other stuff. Also your guys opinions are worth more than just 2 cents! :hide:

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Best way to "feel" the trans up is to jack the rear tires off the ground. Tie your clutch pedal down to take all tension off the belt. Then spin the input pulley by hand. Try it in high and low range and all gears. If you hear any clicking or grinding then you have a problem. With 35 hours I'd bet you're saf.

Good luck!

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Also your guys opinions are worth more than just 2 cents! :hide:

Yeah, you clearly haven't been speaking to my wife and kids! :WRS:

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Best way to "feel" the trans up is to jack the rear tires off the ground. Tie your clutch pedal down to take all tension off the belt. Then spin the input pulley by hand. Try it in high and low range and all gears. If you hear any clicking or grinding then you have a problem. With 35 hours I'd bet you're saf.

Just a warning to all those attending the big show this weekend -- In Pennsylvania, it's illegal to "feel a trans up" in public in the manner described by Cole's dad. :hide:

Seriously, it sounds like a good method, certainly safer than a lot of other ways I've heard about over the years, I'll give it a shot next time I need to test my trans.

Just not in public. :WRS:

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Best way to "feel" the trans up is to jack the rear tires off the ground. Tie your clutch pedal down to take all tension off the belt. Then spin the input pulley by hand. Try it in high and low range and all gears. If you hear any clicking or grinding then you have a problem. With 35 hours I'd bet you're saf.

Just a warning to all those attending the big show this weekend -- In Pennsylvania, it's illegal to "feel a trans up" in public in the manner described by Cole's dad. :hide:

Seriously, it sounds like a good method, certainly safer than a lot of other ways I've heard about over the years, I'll give it a shot next time I need to test my trans.

Just not in public. :)

OH OH.....guilty as charged. :WRS:

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I had the same thing when I got my 312-8. I bought extra oil and drained and refilled it 2~3 times till the oil looked proper.

Runs fine

Francis

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Hi I have a 1989 312-8 that runs away on hills in low range 2 nd gear all the time. In first gear not yet what should I do 

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@Cadmandu  no way a manual tranny should run away in any gear.  My guess is a stretched drive belt that is slipping.  Check and see what kind of shape it is in.  Wipe the pulleys with mineral spirits...the belt also, if it is in good shape.  :think:

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Man is that a good idea thanks so much. I thought I had a bad tranny. I drained the tan colored fluid out this spring and installed a new boot. Can that drive belt be adjusted somewhere? I have a spare 

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Actually no...the drive belt has no adjustment.  The tension pulley does it's thing and there is no adjustment.  What you can adjust is the so called clutch pedal, but that is only for a comfortable height.  Let us know if what I said works for you...please.  :)

If the belt is doing what it is supposed to do, the trans will not take off......there will be a certain amount of slack (like 1' on the ground...or less) because the horse is belt driven, but once the belt catches up the slack, the trans should hold.  Think of a mile long train that has a certain amount of slack between each car because of the hitch.  The engine has to start out real slow to take out that slack, or it will tear a coupiler apart.  That train has to do the same thing, in reverse, to come down a hill.  It has to pick up the slack.

   I'm not positive that this is your problem, but it is the right place to start.  I just don't see it being inside your tranny.

 :handgestures-thumbupright:

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Ok I just mowed a few days ago it was really scary running down a 45 degree bank with the brake smashed and still rolling toward the chicken house. If the belt is okay can I clean the belt and pulleys while still on the machine? After cleaning would the fan belt spray help. Thank how do you put a new belt on without adjustment

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You need to remove the belt guard first.  You will see the engine pulley on the right, the tension pulley in the middle, and the input pulley on the trans, left.  If someone pushes in the clutch pedal, or you tie it down, there is your slack and you can remove the belt.  If the pulleys have some rust...steel wool or sand them, wipe with mineral spirits.  Inspect your belt...is it worn on the edges...hard to tell if it is stretched.  If you have a spare...wipe it with mineral spirits and put it all back together.  You can try the old belt 1st if you want...or after just to see what was really wrong.  Remember...you have to have the guard back on to run the horse...the guard funnels the slack in the belt toward the engine pulley when the clutch pedal is pushed in.  This makes the belt slip over the engine pulley and lets the trans input pulley come to a stop so you can shift the trans without grinding gears.  I hope this makes since.  I think when you remove the guard you will see what I am talking about.  Please...ask any questions.  :)

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That was a great post I needed that. I will just remove the old belt and lay it over the new one and take a picture for you. I will use some Emory cloth and get some spirits. You guys really know your stuff. I was on Craig's list looking for a cheap horse so I could swap the drive. Thanks so much. Can I post a picture

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Of course you can post a picture.  One thing you mentioned above I forgot to address...by no means use a belt dressing!!  absolutely, do not use a belt dressing!!!  Your belt has to be able to slip on the engine pulley when the clutch is depressed or your input pulley on the trans will not stop.  If that pulley does not stop, you can not shift gears with out grinding.  :)

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On ‎8‎/‎24‎/‎2017 at 4:39 PM, Cadmandu said:

...it was really scary running down a 45 degree bank with the brake smashed and still rolling toward the chicken house...

 

I think this is part of your problem.  In my humble opinion, 45 degrees down a hill is way too steep, I think you just locked your brakes and were sliding down the hill, the transmission had nothing to do with it.

 

You say this doesn't happen in 1st gear low range, presumably with no brake necessary?

 

 

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No I will be going down the bank in 2nd gear low range and all of the sudden it will brake loose and just run off with me. It use to be only once in a while now every time. I have to do a brake job on wife car today so Monday I will look at the belt.

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I am thinking the same as @tunahead72 on this one. The transaxle has a differential and your braking force will be applied to the tire with the least amount of traction. This is true for transmission braking and/or applying the brakes. The brakes stop the transmission from turning, not the wheels.

Also, your engine has a splash lubrication system and if you spend much time on an angle greater than 25 degrees you will ruin the engine.

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