HST Oil Change: Fact or Fiction?

[IslandTractor]

I have to agree with those who are skeptical about the need for changing HST oil regularly. Automobile transmissions are more abused than tractor HST and the rule in autos seems to be that if the fluid smells burnt then change it. My HST oil is very clean and at 500 hours (actually 400 on the oil as I did an initial change per factory schedule) it is the equivalent of an automobile at about 12,000-20,000 miles. Nobody changes auto transmission fluid that frequently.

I'm waffling for two reasons. First is whether it is necessary. Second is that a neighbor who sold his JD backhoe gave me three pails of fresh but generic HST oil. Can't decide whether to change and if so whether to use the free oil.

 

[LD1]

If you have an old backhoe like mine, there is never a need to change the oil.....only the filter every once In Awhile. The oil is always like new....constantly having to be replenished to replace what leaks.

 

[mcfarmall]

Heat degradation, the depletion of the additive package, and contamination are the main concerns.

 

[newbury]

Trust but verify. Get a used oil analysis if you are worried.

 

[IslandTractor]

Trust but verify. Get a used oil analysis if you are worried.

I've never heard of a used oil analysis on hydraulic fluid. How does one interpret the findings? Does the analysis give limits of normal for contaminants and additives?

 

[hosspuller]

Hydrostat oil like auto transmission oil suffer wear particles, oxidation, etc. The other property not yet mentioned is viscosity loss. As the oil is churned and sheared, the molecules are broken down. The newer sealed transmissions have synthetic fills but even they are not immune to viscosity loss. It's just enough to get the unit safely out of warranty :thumbdown:

 

[newbury]

I've never heard of a used oil analysis on hydraulic fluid. How does one interpret the findings? Does the analysis give limits of normal for contaminants and additives?

Here's an explanation

 

[IslandTractor]

Here's an explanation

Thanks. Where do you get hydraulic fluid tested?

 

[newbury]

Thanks. Where do you get hydraulic fluid tested?

I'm getting mine done at Blackstone Labs, but that's just because I bought a bunch of their prepaid mail in test sample containers a while back.
There's a lot of testers out there.
Check with BITOG (Bob is the Oil Guy)

And as I posted in another thread getting the sample is easy:

I admit it might be a terrible, difficult, messy project for some.

I worked the tractor (B7610) for a while to ensure warm hydro fluid.

I turned it off and lifted the seat.

I pulled out the fill plug above the three point.

I stuck a CLEAR aquarium air tube down inside and siphoned out the required amount.

Use a clear tube so you can see it.
Get the fluid warm if not hot so it flows quicker
Wipe off around the plug before pulling it.

The messiest part was the two or three drops of fluid out of the tube after I was done. But I had a full roll of paper towels handy.

 

[fatboycowen]

Blackstone is good. I also heard somewhere that caterpillar dealers can send them out for you.