8 speed Uni Drive Oil Change

[JamesD 6]

I'm more of a lurker than a poster but I need to ask a few 8 speed questions. I have a 312-8 that I am the second owner of since September 2020. I purchased this off of a dealer's lot that took it as a trade for a Kubota zero turn. I purchased it purely for the transmission after burning up a K46 on a John Deere. I rarely mow with it and use it to tow a utility cart and a Trac Vac leaf collection/vacuum system that weighs around 165 lbs empty. My property is built into a hillside so there are some steep grades going from front to back the grades can be 5-8% in some places. When I purchased the tractor my local small engine experts assured me the transmission was bullet proof and not to even bother with the oil it lasts forever in these transmissions. After two years of owning it my curiosity got the best of me so I checked the oil and low and behold it looked like whipped cream. So I put some diesel in the tranny and drove it around for a while to try to liquify the old oil and drained it. I replaced the oil with STP 90W gear oil and went about my business. I check the oil once a year and this year the stick had some foam on it although the oil looked good, I'm averaging about 25 hrs per year and the tractor only has 750 hours on it.  I drained the transmission and some of the oil looked new, some looked greenish and thick, and there was a small amount foam floating on the top. My questions are 1) I don't think I stress a machine designed for groundwork by towing cart and Vac Trac what is causing the foaming? It seems like moisture intrusion but there are no leaks that I can tell. 2) what's the best way to fill the transmission with oil? I use the dip stick opening but it is a royal PITA and I get oil everywhere. 3) I put two quarts of oil in but I seemed to have overfilled it according to the dip stick, should I drain it down? is it ok to have too much oil in the transmission? 3) How much heat and pressure do these transmissions generate? I'm an awful mechanic but I love my outdoors work with my equipment and this tractor is a beast for me so I want it to last 20 more years. Any answers would be helpful, thanks.

[Achto 29,806]

25 minutes ago, JamesD said:

My questions

 

1 - Does not sound like you are over stressing the machine at all.

2 - Filling through the dip stick hole is what I do. If you drop a small hose in the hole while filling, this will let the air out so that it does not bubble back on you.

3 - 2 quarts is a little over full but not a huge deal.

4 - The heat generated in the manual tranny is not that significant.

 

The foaming may just be inherent of the type of oil. My fav is Lucas 80-90w. But most heavy oils would be a good choice.

 

When you drain the old oil out, you should raise the front of the tractor as far as you safely can. There is a hump in the bottom of the tranny that prevents about a cup of oil from being able to drain out. 

[953 nut 62,155]

Nothing I can add to what @Achto already said.    The green stuff and the foaming could be residue from the old oil you loosened up with the flush.

[AHS 1,562]

It will last you another 20 + years! Don’t be concerned about the heat… traveling at 6-7 mph tops! So, i would replace the shifter boot, the shifter boots are cracking at 20+ years! Check on ebay, that’s where i get my shifter boots. Change your oil at least once per year. 

 

I have a ‘73 Kohler 14hp/Auto (summertime lawnmower!) and that motor is tougher than a bags of hammers!

[JamesD 6]

Thanks guys much appreciated.

[ri702bill 10,036]

I am sure that @ebinmaine can add more on this. Over time, the additives in oil break down and loose their exxectiveness. That includes the anti-foaming agent.....

 

[ebinmaine 74,545]

2 minutes ago, ri702bill said:

additives in oil break down

 

3 to 5 years absolute max. 

 

8 hours ago, JamesD said:

my local small engine experts assured me the transmission was bullet proof and not to even bother with the oil it lasts forever in these transmissions

 

 

I'd be looking for different shop....

 

[ri702bill 10,036]

1 hour ago, ebinmaine said:

I'd be looking for different shop....

And buying 10 year old unopened NOS oil at a flea market for use in any vehicle is throwing away your money... 

[JoeM 8,887]

Wheel Horse manual transmissions have straight gearing and will pretty much run on anything from motor oil to 80w-90. Using the machine to pull a cart would be considered intermittent loading. I don't think the oil temp would get much higher than ambient.  

 

Using a good oil or grease is best practice and yep there is a shelf life if unused. Nothing wrong with using the best if you can afford it.

When in doubt change it, cheap insurance. 

I like buying my oil at places that have a lot of turn over. I am sure some folks here have gotten a tube of grease that has started to separate. 

 

After tinkering with these transmissions, water is the biggest enemy. Most gear lubes will not loose any lubrication quality up to 1%, and they have rust inhibitors in the blend. Unfortunately the WH case is not painted inside and rust will form on the inside top of the case. The case is splash lubricated and nothing coats that area. 

 

Back in the day, I used Chevron and they always had bulletins concerning their oils and greases. It was nice to have an lubrication engineer available too. But that is the big bucks game.

Here is their take on oil shelf life.

 

[rmaynard 16,586]

Many Wheel Horse manual transmissions have been running with old, water-contaminated oil for many years, even decades. My opinion is that any fresh transmission oil is better than that. Though the Uni-drive transmission is not bulletproof, it's pretty close.

[ri702bill 10,036]

12 minutes ago, JoeM said:

 

After tinkering with these transmissions, water is the biggest enemy

Agreed... the second greatest offender is the doofus that insists on speed shifting one of these while in motion. Then they wonder why it pops out of high gear...

Edited 9 hours ago by ri702bill

[peter lena 9,453]

@JamesD  regularly  check my trans oil , no surprises ,  also always  use a similar cleaning oil  . personally like hi mileage  ATF  , as a cleaning flushing agent  , also put time on that / miles , regularly refer to cul-de-sacs , for safe driving time , use every gear  / range ,thats important to  visualise  that  lighter oil flushing / rinsing down the  gearbox ,also drain it with  jack stands  under front end , a new shifter boot  , with  underside of that  greased ? to slide over the irregularities', on top of gear box , also like a bIg TYE WRAP . on the top of that  boot , after it tells you where , IT WANT,S TO  BE  , mine last a long time , also like the lucas oils , climbing  ability , we all have our own favorite , change it at any discoloration  check , also have a regular check over  on my horses . do it after  EVERY  USAGE . engine oil check , trans oil , top off tank , add 1- 2 ounces of   stabil  fuel storage , REPITITIONS  OF PROBLEMS . are your  tracking , personally like to make them go away , rarely have a failure  , due to not responding to issue , pete