M6 trans fluid

[Doug&Deb]

Is ISO 32 hydraulic oil what others are using in the M6 trans? I’ve used floor jack oil in the past with no problems but I have access to hydraulic oil at work so I’m just wondering.

[greg g]

In the trans it self or to top off the fluid drive unit?

[Doug&Deb]

Trans. I’m overdue for a fluid change. 

[greg g]

I believe SAE 10 is what is recommended for the m6.  The imperial Club has a lot of info on the semi autos in their repair section.  Might be worth a look there.

[Dodgeb4ya]

SAE 10W or equivalent.

I've run 10/30 in this trans just to see...quicker upshifts and delayed auto downshifts...

Tractor hydraulic oil would work of the correct viscosity.

I always have bought it (10W)by the case for rebuilds. 

It's still available...but you do need lube of a close viscosity to do it right.

AW32 hydraulic oil is 10W.

One thing...on a high mileage transmission....

if the oil pump and piston is worn and barely able to build 40-50 lbs oil pressure AW46 oil could be used to be sure of positive upshifts.

Edited November 13, 2020 by Dodgeb4ya

[Doug&Deb]

Thanks everyone 

[Merle Coggins]

Not all hydraulic grade oils, or engine grade oils would have the anti-shear additives necessary to hold up in a gear box application. I'd be looking for an oil that is rated for use in transmissions.  

[Tom Skinner]

Tractor Supply used to sell gallons of 10 wt. non-detergent oil, no more.

I went on e bay and found a Hardware Store (In Texas)that sold the quarts for about $4.00/per qt.

You need 2. The only problem was their shipping and handling was another $12

So for $20 I changed my m 6 transmission fluid. Remember to open up the screen (bottom left at rear of transmission)

plate and clean in in kerosene and re-install with a gasket. There are also a couple of valves and springs to check for cleanliness

and free movement at the bottom of the transmission (near under the Governor region - bottom right rear of the transmission)

That should do it. Good Luck

Tom

[Jeff I indu]

This is what I use in my 49 chrysler fluid drive transmission. Someone on this site recommended it. My local Grainger store carries it for around 30 or 35 dollars. My transmission shifts fine

Jeff

[Dodgeb4ya]

Like Merle mentions....the pressure and shear on the gears...is std hydraulic oil up to the job?

IDK....."bob is the oil guy" could answer that.

 

[kencombs]

39 minutes ago, Dodgeb4ya said:

Like Merle mentions....the pressure and shear on the gears...is std hydraulic oil up to the job?

IDK....."bob is the oil guy" could answer that.

 

Most major brands of hydraulic fluids are intended to be used in machines with common reservoirs for the transmission, differential and hydraulic pump system.   My little JD garden tractor is speced to use JD Hygard, low viscosity in the transaxle.  wet brakes, wet PTO clutch, differential and hydraulic pump.   Interestingly enough, the maker of the transaxle (Tuff Torq) recommends 5w50 full synthetic motor oil in the same unit installed in other make machines.    I think the Hygard is ISO46.  It is recommended for almost all JD equipment for mowers to huge construction stuff.

[Doug&Deb]

I think it’s important to remember that 10W non detergent oil was originally used. The important thing is to change the oil frequently. Of course I’m the one that’s overdue for an oil change in my trans so I’m a good one to talk about frequent oil changes. I’m going to try the AV32 hydraulic oil and see how it works. I believe it’s the same thing as the floor jack oil I’ve been using for the past 7 years.