Reducing noise with fluid change RX7320

woolyAcres · Sep 3, 2018

Hi Gang, I'm approaching the 50hr service on my RX7320 and like FEG (https://www.tractorbynet.com/forums/kioti-owning-operating/400383-kioti-rx7320-cab-noise.html) I find my cab to be noisier than I'd like. It's not engine noise, it's gear whine and it's worse under load.

I wonder if I might be able to reduce this with a better/different choice of hydraulic/transmission fluid at my 50 hour service.

I know folks on TBN really like SUD2 and I've seen recommendations of Mobile 424. I need to review the actual specs to make sure what ever I put in it will meet manufactures warranty requirements but I'm interested in feedback from folks about the likely hood of a fluid change making the transmission quieter.

MickeyDBC · Sep 3, 2018

SUD2 is crazy expensive but 424 is only about $40 a pail from my local oil distributor so I would try the 424. I blew a hydraulic seal and had to add 5 gallons of 424 to mine and did not see any noise change. The funny thing is that they are super quiet outside but not so much inside. It seems like most of the noise is coming from under the seat (probably no sound proofing on the bottom of the panel) and maybe add some foam sound insulation under the rubber mat on the floor. But to be fair I did drive a Case that was just as loud when I was shopping but the Kubota that I drove was quieter. Sounds like a good winter project.

woolyAcres · Sep 3, 2018

There was a post on TBN in the last few week suggesting a couple places to buy it online. I'll go back and dig those up. I did check the manual today and it looks like the Mobil 424 is a manufacture recognized option so I might go that route. I'm planning to call the dealer this week to figure out what filters, etc I need. Perhaps they have some comments/suggestions; I'll also get pricing on the Kioti fluids.

Anyone have comments about how the Kioti fluid compares to the Mobil 424?

Wilco · Sep 3, 2018

I did the 50hr using Mobil 424 in my CK2610HST. I don't notice any change in sound or operation. I made sure I listened to the tranny whine and loader operation before changing the fluid as others had mentioned the difference it made. The hydro fluid that came out looked super clean...wish I had just changed the filters per owners manual and saved myself 100$.

Wilco · Sep 3, 2018

Summit Racing seems about the cheapest online for Mobil 424....Over $100 qualifies for FREE shipping.

iflywhatevr · Sep 3, 2018

I switched to the SUD2 on my CK3510 HST. It was more expensive than say the TSC junk but really not all the bad. It did a good job quieting down my hydraulics.

woolyAcres · Sep 4, 2018

iflywhatevr said:
I switched to the SUD2 on my CK3510 HST. It was more expensive than say the TSC junk but really not all the bad. It did a good job quieting down my hydraulics.

I think I'd be willing to pay up-front for the more expensive fluid if I had confidence that it would reduce the noise. I can't remember when the next trans service is but it's several hundred hours away (years) for which my ears will be very grateful. However, I'm not sure that SUD2 is specified as manufacture as an appropriate substitute. Plan to talk to the dealer this morning.

woolyAcres · Sep 4, 2018

I spoke with the my dealer today and the service tech there said he'd expect a noticeable change with the 50 hour service; replacing the trans filters. He also said that unfortunately the Kubota fluid wouldn't be acceptable because it's not called out specifically in the owners manual. He did admit that at their shop they use Case Hy-Tran. They are a big Case dealership and have permission from Kioti to do so. But I'm not a shop and I don't have permission from Kioti to use the Kubota stuff even though it's mostly likely every bit as good.

I think I may take his advice and go with just a filter change to see if that will solve my issue. If not, go with a changing out all the fluids.

DieselBound · Sep 6, 2018

There's SUDT and SUDT2.

Not sure if one can glean industry specs (ISO/SAE) from Kubota's fluids or not, but there should always be such as there's a law stating so (I don't think any manufacturer can guarantee that their fluids will always be available, and that's why it came about that it must be stipulated that industry specs be made available such that people could locate alternatives).

I "reverse engineered" hydraulic fluid specs for my Polaris using MSDS information: found an alternative, and cheaper, fluid that matched up based on MSDS.

Manufacturers cannot certify every brand of fluid. They will contract with one company for pricing, but are supposed to provide industry specs such that other possible candidates can be located/used.

woolyAcres · Sep 27, 2018

I did my 50 hour change a month ago. When I pulled out the filters to change them, there was a good bit of sludge on the magnets and presumably in the removed filters as well. I did not change the fluid- it's not part of the 50hr service. It seems quieter but I haven't measured it with my phone-based sound measurement app.

So I guess my update is it seems quieter but I don't have any evidence of that. Still not as quiet as I'd like but I need to remind myself it's a 10,000# machine pulling 12' transport discs. It's got to work hard to do that.