RK 24 H TRANSMISSION/HYDRAULIC FLUID TYPE

[RickDpwv]

Paul, THANK YOU VERY MUCH for all the info! That's exactly what I needed/wanted to know! I'm saving and printing the info you provided to keep with my tractor 'forever papers'. You sir, are a fine example of what makes this forum great; sharing of knowledge so we all don't have to learn from our mistakes!!

 

[OhioCowboy]

Rick, Thanks. We'll all work together so we can work on and use our RK24 and what RK will help us with. I'm on the hunt now for synthetic Universal Transmission/Hydraulic fluid. It looks like Kubota has synthetic available. I got the synthetic GL-4 gear oil for the front axle ordered. Now if mother nature will just cooperate this Spring. Lots of projects planned for the RK24 FEL and backhoe!

 

[RK Tractor Guy]

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[OhioCowboy]

RickD, I agree. I know that it's very difficult to find GL-4 gear oil for the front axle. Doing a search of GL-4 vs GL-5 gear oil presents a ton of discussions about the differences. It goes from "it will destroy your differential" to "GL-5 is an improved GL-4". Personally, until the warranty is up, when I do my own maintenance fluid changes I'm going to use GL-4 gear oil for the front axle . I'll use the RK Universal Tractor Fluid or a synthetic tractor transmission and hydraulic oil if it meets the specs in the PDF manual. Unfortunately the RK Universal Tranny and Hyd oil did not say it met GL-4. I think RK should carry a fluid that lists their own tractor on it. Or their manual should list a spec we can find on the fluids they do carry. Even if it has to be IH, JD, MF or NH.

These are the tranny and front axle fluid specs listed in the PDF manual I downloaded from RK:

Transmission (3.83 gal)
(API GL-4 Grade) Tractor transmission and hydraulic oil
Below -4ｺF(-20ｺC) ISO VG32
Above -4ｺF(-20ｺC) between ISO VG46 and 68
Front Axle (.85 gal)
(API GL-4 Grade) Gear oil #80 or #90

For what it's worth, here's an important point on RK24H front axle oil: Use only GL-4. DO NOT USE GL-5. (It is not a "new and improved" GL-4)
It is difficult to find GL-4 locally here. Everyone has GL-5 and that's what they want to sell me when I ask for GL-4.
I have not seen the Harvest King Gear Lube MP 80/90 that RK recommends. The online description does not specify the API and no image to look at.
I bought synthetic online. (Red Line 50305 MT-90 75W90 GL-4 Gear Oil)

 

[BoneStock]

I recently spoke with my RK salesman and had him print their service manual for the tractor. Use a Trans/Hyde oil. My manual said use a gear oil for the hydraulics, must be a misprint.

 

[OhioCowboy]

Transmission
(API GL-4 Grade) Tractor transmission and hydraulic oil
Below -4ｺF(-20ｺC) ISO VG32
Above -4ｺF(-20ｺC) between ISO VG46 and 68
Front Axle
(API GL-4 Grades)Gear oil #80 or #90


The above specs calling for GL-4 Gear oil for the front axle are from the current manual for all tractors downloaded from the Rural King website. Page 5-11 Dated 2018. My experience dealing with the sales people and the service department leaves me to believe the service department has the most current info and is more knowledgeable about servicing the tractor. But, that's just me and my tractors. As long as I'm doing my own maintenance and keeping records in case of a failure, I'm following the published Rural King manual (and keeping copies of the PDF in case of updates)
I checked all the tractor manuals fro RK19 to RK74 and this is the spec for each one of them.

This is the date of the manual at the bottom of page 5-11

 

[RK Tractor Guy]

Sorry for any confusion, here are the guidelines straight from the tractor manufacturer chief engineer.
Transmission: Only GL4 Trans/Hydraulic
Front Axle: Either GL4 or GL5 80W90 Gear Oil