50 Hours HST Fluid. Some are crystal clear, others are dark and murky?

   / 50 Hours HST Fluid. Some are crystal clear, others are dark and murky? #1  

bp fick

Super Member
Joined
Aug 15, 2009
Messages
5,715
Location
Beaver Creek, Northern Michigan
Tractor
John Deere X390
As Kubota is moving toward just changing the filters at the 50 hour mark, on most models that I've heard about, it has always just made sense. If the screens and filters do their job, it just makes sense to go ahead and keep the somewhat pricey HST fluid in there, rather than dumping it.

Some guys who dump it anyhow sort of regret it, as they report their fluid was crystal clear and pristine. Others report that even at 50 hours their fluid came out dark, murky and polluted looking and were glad they dumped it.

I suppose one could just draw off a sample, off the bottom of the trans and make a decision. Why some tractor's fluid is pristine while others is all murky looking is a bit of a mystery. I reckon it may have something to do with the luck of the draw. Just how clean everything was at the factory before being filled? I'm sure the machining and castings create a certain amount of "gunk", dust and bits that account for this difference?

Just pondering on this beautiful sunny morning, getting off to a slow start. :laughing:
 
   / 50 Hours HST Fluid. Some are crystal clear, others are dark and murky? #2  
I believe a lot has to do with break-in. Mine was run fairly easy at lower rpm and load, and the fluid was clear at fifty hours. Others say it is a tractor, (my dad, and of course he also wonders why he has so many equipment issues) and run them hard from the get-go. Machined gears need to be burnished to smooth out and harden the contact surfaces and the best way is low loads for the first few hours. If you read break-in procedures for tow vehicles, the tell you not to tow for the first 2500 to 5000 miles. That is actually to break in the differential and prevent galling of the ring and pinion gears.
 
   / 50 Hours HST Fluid. Some are crystal clear, others are dark and murky? #3  
they are going towards just filters, however there are mixed opinions on that.
 
   / 50 Hours HST Fluid. Some are crystal clear, others are dark and murky? #4  
I wonder if differences in fluid conditions could be attributed to what attachments are on tractors and sharing the fluid from the system such as front end loaders etc.
 
   / 50 Hours HST Fluid. Some are crystal clear, others are dark and murky? #5  
Some guys who dump it anyhow sort of regret it, as they report their fluid was crystal clear and pristine. Others report that even at 50 hours their fluid came out dark, murky and polluted looking and were glad they dumped it.

Dark and murky is good, since that is what Kubota UDT looks like new.
Same for JD J20C, Chevron THF, Conoco 76 THF, etc. They all look
and smell the same to me when new. Prob same formula, intended
for tractors with HST and wet brakes.

My first new tractor had HST, and it came with some sort of clear
hydraulic fluid, like ISO 46. NOT the right stuff, so I dumped it all at
50 hr. I still suspect that some tractor makers are using cheap hyd
fluid for the breakin period.

It makes good chain lube for the chainsaw fleet.
 
   / 50 Hours HST Fluid. Some are crystal clear, others are dark and murky? #6  
I wonder if differences in fluid conditions could be attributed to what attachments are on tractors and sharing the fluid from the system such as front end loaders etc.

I would think it could come from older 3PH attachments with cruddy hydro fluid..Probably just a slight color change due to the limited amount in the existing lines...No one talks about that though...My fluid on my BX and RTV were clear at 50..Never attached any old stuff to either though.
 
 
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