OIL FOR TUFF TORQUE K61

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What would you use in a Tuff Torque K61 Hydrostatic Transmission? I've been looking it up and I get 2 different answers...5w50 and 10w30. I live in VA and don't work it in below freezing temperatures.
 
I have a Tuff Torque hydrostatic on my Simplicity yard tractor. The manual calls for "high quality 10w30 motor oil". I have used regular Mobil 1 10w30 since I drained the factory fill after the first season. I drain every 2 or 3 years depending on how much I use it in a given season. I know these hydrostatics run hot, and the used oil comes out clear but noticeably much darker than virgin oil. This year I used Mobil 1 10w30 Extended Performance for the first time. The transmission is 14 years old and runs great.

Something you may want to also consider is a product Amsoil makes that is specifically intended for this application. It is their ATH Synthetic Tractor Hydraulic/Transmission Oil 5w30. Product info states: "Formulated for combinations of transmission, hydraulic systems, final drives, power take-off systems and wet brakes. Engineered specifically to meet the tough applications of heavy-duty farm and industrial equipment as well as commercial and residential lawn tractors. Ideal for lawn tractor hydrostatic transmissions." I may give this a shot next time.
 
Originally Posted By: Gebo
What would you use in a Tuff Torque K61 Hydrostatic Transmission? I've been looking it up and I get 2 different answers...5w50 and 10w30. I live in VA and don't work it in below freezing temperatures.


I called them personally and was recommended a 50w auto oil. Used Mobil 1 15w-50 and it is MUCH quieter!

Couldn't be happier.
 
I have a simplicity lth12.5. Made in 1990, makes it 24 at the end of the seaon. Simplicity calls for 15w40 in engine and nd30 in the hydro transmission.

I have had a ingersoll ztr a few other name brands plus a husler all had mandated Mobil 1 15w50 only. I personaly the filter every engine service and fluid everyother engine service. I used Mobil 1 or napa 15w50 or castro 5w50.

Never had a single failure.

Ken
 
I just put Mobil 15w 50 in my K61 as well. Been running Mobil 5w30 for years but somewhere along the line tuff torque changed the viscosity I found out.
 
I am trying the Castrol 5w-50 and seems better. It will back up hills in reverse and not bog down. IT will go til the rear wheels spin. With the 5w30 it would stop pulling. Go figure...
 
Last night I finely was able to change the oil in my tt k57 in my simplicity. Getting the unit out was a royal pita! I too went with mobil 1 15w50, after everyone's info and tt recom 5w50.

When in popped off the cap WOW! the oil was as black as a 7k oil change, was a tad low also. After checking other sites i now know why everyone changes them.

After about 3hrs start to finish (sharpend blades) done and went for a spin. What a difference, soo much more responisive, speed and pullling power, the engine actully has a load on it vs b4 it didn't notice.

Napa has Mobil 1 on sale $5.99qt till eom. My local store even had 5w50! So after abt 3hres and $13 my mowers runs like new, it has 275 hrs on ff. That was worth doing, at least save me $1000 for another transmission.
 
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My son has a K51 in his LT166 . It's not got much reverse and he has a pretty good hill on the west side of his front yard and says it struggles uphill (actually stopped) with him and his 4year old on it . I'm thinking it best to rebuild it off season but maybe it's worth giving the 5W50 a shot ??
I would hate taking the time for the R&R just to have a minimal improvement .
Rebuild will cost about $250 for the parts from TT .
 
nitehawk, I would try the oil change first.If it doesn't help drain and strain the new oil and pour it back in after the rebuild. Just my .02
 
Originally Posted By: nitehawk55
My son has a K51 in his LT166 . It's not got much reverse and he has a pretty good hill on the west side of his front yard and says it struggles uphill (actually stopped) with him and his 4year old on it . I'm thinking it best to rebuild it off season but maybe it's worth giving the 5W50 a shot ??
I would hate taking the time for the R&R just to have a minimal improvement .
Rebuild will cost about $250 for the parts from TT .


I've had good luck with the Mobil 1 15w50 in mine. Significant difference in pulling power.

Also, rigging is very important on these things. Mine (a JD garden tractor) would not achieve full forward and therefore would not reach the blistering top speed of 7 MPH. AND reverse was limited to about 50% of available lever travel, due to rigging and mechanical stops. I changed all that and it's far better.
 
I just wish they made these lawn tractor trans-axle`s easy to service. I have a Hydrogear with a drain and fill plug. But I cant get to the fill plug.
 
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