RK55 HST Transmission Oil

[Terminknotor]

I have a RK55 HST tractor that the manual calls for API GL-4 and ISO between VG46 and 68.

Rural King is almost 2 hours away so I am trying to find a suitable substitute for that meets the above either at Tractor Supply or any Auto Parts store.

The oils at Tractor Supply dont say both of the above, they simply say J20c certified or something similar.

Has anyone with an RK tractor solved this riddle yet? Thanks very much in advance!

 

[Fergenheimer]

My RK24 manual calls for the same as you say above. But this is what the mechanic at RK said they use and so I bought for my RK24. Providence is an RK brand but they said use anything labeld as TRANS-HYDRAULIC OIL. There is nowhere on the label that I could find that gave an ISO viscosity designation. I had 2 Gallons of ISO 68 Hydraulic fluid in my cart and they said to never use that! They had just done the 50 hour maintenance and said the one shown below is what they used for that tractor. I chose to keep the oil the same. I also think that if you find any ISO 46 or 68 hydraulic fluid it will be good. I would use 46 in cold climates and 68 down south.

 

[Fergenheimer]

So the GL-4 is 90 weight gear oil, it is for the front differential. I pulled down your manual and on Page 5-11 it gives
▶ Recommended Transmission
oil
1. RPM tractor Hydraulic Fluid or
Textron TDH Premium (CALTEX)
2. TDH Oil or TDH Oil special
(TEXACO)
3. Chevron 1000THF (CHEVRON)

Other threads on here show that MOBILFLUID 424 meets the requirement and is available at TSC.

 

[ericm979]

Other threads on here show that MOBILFLUID 424 meets the requirement and is available at TSC.

Yea it's very similar to the Chevron stuff. They changed the name recently to Delvac.

Do not use straight hydraulic fluid in an HST transmission. The wet brakes and clutches will chatter. Tractor fluid has additives specifically for wet clutches and brakes.

Gear oil for the front axle.

 

[jigs_n_fixtures]

When I asked the mechanic at the TYM dealership, what to use they said they use a Shell Tractor Hydraulic fluid, Spirax S4 TXM for summer, and Spirax S3 TLV for cold weather, such as snow plowing. Other options are Rotella in the various grades. Just be sure it is specified for wet brakes.

 

[Robin Veerman]

Or try AMSOIL tractor hydraulic/transmission oil. I run it in my Kioti HST tractor and JD X390 lawn tractor. No need for seasonal change as it’s great in hot/cold weather.
I’m Very happy with it. If you can’t find it locally, just order online and it’ll be on your porch in a day or two.

https://www.amsoil.com/p/amsoil-5w-30-100-synthetic-tractor-hydraulic-transmission-oil-ath/?zo=331384

 

[Williy]

Have you seen this?????

GL-5 gear oil is a good alternative to GL-4 gear oil for hypoid gear systems because it has about twice as much extreme-pressure (EP) additive. This provides better protection, performance, and efficiency. However, using GL-5 in a transmission that requires GL-4 can cause synchronizers to wear out prematurely.

willy