Change hydraulic fluid at 50 hrs or not?

[ritcheyvs]

... Auto trannys use hydro fluid because they are basically hydraulic pumps (as is power steering)....

This isn't quite right. Auto trannys in cars use gears and bearings and seals just like manual transmissions. But the various gear paths are engaged through (hydraulically operated) bands and clutch packs; also a torque converter at the front end allows variable slip with torque gain. On the other hand hydrostatic transmissions (like in tractors) are quite different and are much like your description.

 

[xring100]

I'm new to tractors, but not cars. Axle fluid in cars (and manual gearboxes) is heavy grade 80or 80w-90 or such. I always thought it was because gears act against/with fluids differently and their bearings are different. Auto trannys use hydro fluid because they are basically hydraulic pumps (as is power steering).
I don't see how 10w-30 or 80w-90 will fulfill the same role. Not saying I'm right, just confused.

Actually most gm manual transmissions in the cars at least in the last 15 years or so call for ATF not gear oil

 

[blucoondawg]

I changed the engine oil/filter and the hydraulic oil and filters today. I did find 5 small metal slivers on the sump magnet and the usual metallic fuzz. The fluid looked fine when I drained it but when I put it in a clear container for recycling it was much darker than new fluid. Good to get new fluid in there after the break in period.

Still have to do the front axle. The book says either 90 weight gear oil or use the transmission oil (i.e. Mobilfluid424). I was planning to use the latter since I have several gallons left. Any issues with that? (Not that I don't trust the owner's manual :confused3

I used mobil 424 in my axle. It has been debated on other threads which way to go but seems to be personal peeference

 

[Buggs67]

Actually most gm manual transmissions in the cars at least in the last 15 years or so call for ATF not gear oil

I did not know this. My current car calls for 80w-90. So I changed it out at first opt with synthetic. BTW Almost surprised GM still offers a Manual trans

 

[TomSeller]

Almost surprised GM still offers a Manual trans

They are the best anti theft devices available. A couple of kids took the keys away from an old lady recently and after getting in the car, took off on foot.

 

[Hill Billy Bob]

It is a conundrum. But the manufactures often specify either for the front axles of tractors.:confused3: Is it because the front axles of tractors operate at such low speeds? I don't know.

It is because the modern, multigrade, UTF's, (Universal Tractor Fluids), meet the API GL-4 spec as a gear lubricant. This is the same spec that an 80 or 90 weight gear oil meets. UTF is a bit more complex than standard hydraulic oil, and of course, our Kioti's all use UTF, not hydraulic oil....Bob

 

[xring100]

I did not know this. My current car calls for 80w-90. So I changed it out at first opt with synthetic. BTW Almost surprised GM still offers a Manual trans

Yeah they sell a fair amount of cruze eco manuals. My 1996 saturn SL1 manual also used ATF. My guess they switched to ATF for fuel economy advantages like the oems have done switching from 10W30 to 0W20 in most of the gas engines.

GM Still sells a lot of manuals globally. You could still buy manual transmissions in the full size pickups in Mexico as of a couple years ago.
These days Americans just tend too be lazy or to busy drinking coffee, reading a book, and sending text messages all well shaving or applying makup. I would have bought a cruze diesel manual if it had been offered. I had to settle for the auto instead. I put amsoil full synthetic gear 80w-90 oil in the front axle and hubs (yes it has 3 drain plugs and 3 fill points) in my tractor.

 

[Buggs67]

Actually, now I'm thinking I WILL change mt UTF. The setup dealer probably filled the tranny and front end. I assume the tractor comes bone dry from Korea. So what did he put in?? M guess is whatever's cheep. Maybe this will cut down on the whine (and I don't mean Merlot ).

 

[oldpilgrim]

Is it because the front axles of tractors operate at such low speeds? I don't know.

the front axles turn much faster than the rears, on those machines where the front wheels/tires are smaller than the rears.

 

[dfkrug]

The setup dealer probably filled the tranny and front end. I assume the tractor comes
bone dry from Korea. So what did he put in?? M guess is whatever's cheep.

10 y ago when I bought my 1st new Kiotis, I tried and could not get a definitive answer as to what brand/type
of trans oil was in there, and who did it. The trans and front diff are not shipped dry, since they
are likely tested and driven off the assembly line. Final dealer assembly only includes wheels & ROPS, for the
most part. I got mine in the crates from Korea, and they were full of oil. No battery, however.

Cheap 5-gal drums of generic clear hyd oil is my bet, knowing it is break-in oil that is required to be drained
in 50 hr.

BTW, Honda has been using 10W30 motor oil in their manual trannies/final drives for more than 25 y, and their
gearboxes live long. I don't know why 80W and 90W gear oils are still so common. Tractors move slowly
and dissipate little power, so I suspect that is why they can get away with hyd oil in the final drives.

The new Corvette has a SEVEN speed manual tranny; I would like to see more of those.