G1000 transmissions/differential oil

What oil (type and viscosity) do you guys recommend for the transmission and differential on the MM G1000. The books I have just say use MM quality oil. No mention of viscosity.

Also, the manual mentions a transmission filter, but I do not see one on our tractor. And suggestions of where it might be?

Thanks,
Ryan

We always used Mobil 424 oil in our G 1000 Vista. It should be the same in your G1000.
http://www.mobil.com/USA-English/Lubes/PDS/GLXXENCVLMOMobilfluid_424.aspx

And just to add that any comparable oil such as HY trans should work.
The filter should be on the side in a canister. Follow the lines from the lube pump should lead you to the filter. Hope this helps.

I know a few who run hytran.

I might be the only one.. but I have repaired many G1000 trans that have used hytran. I have repaired none that use 85-140 synthetic.

Let me add my two cents worth to this discussion as it seems to come up quite often, and I would also make the point that I am not recommending one type of oil over another - just providing something to think about.
Some time back, I was changing the oil in the rear end of a couple of G1000s. I also asked questions on this site and was very appreciative of the feedback. For these tractors, the Oil Companies of today recommend a dual purpose transmission/hydraulic oil. These oils are typically lower in viscosity than traditional gear oils. But these tractors have a separate hydraulic compartment, and don't have wet brakes, so the transmission oil has no need for any hydraulic function. These tractors also have a transmission oil cooler and a lube pump to circulate the oil and help dissipate heat from the transmission and rear end.
I work my tractors and for that reason I use an 80W-90 gear oil. The Hy-Trans type of oils may also be good, but I just feel better that when out in the field and things get hot and dirty, I have taken the best care possible of the transmission and differential.
There is also a screen filter in the differential. This screen filter screws onto the suction tube of the lube pump. It's hard to get at but needs to be clean.

If you are going to do heavy work with the tractor, the straight cut gears and the bearings will last better with the higher viscosity oils originally intended for the tractor.

With lower viscosity oils you run the risk of running the gears with metal to metal contact which will eventually cause pitting and scoring on the face of the teeth. The lower viscosity oils work well in tractors that have helical cut gears running at higher pitch-line speeds than MM gears because the newer tractors often have planetary final drives keeping the torque low and speeds high until the final reduction stage. The higher pitch-line velocity and helical cut teeth helps to maintain the oil film in the newer tractors preventing the metal to metal contact. Thus, thinner oil can be run in the gearbox which reduces the power loss in the gearbox due to churning delivering more power to the wheels.

The same basic concept applies to the bearings. The lower viscosity oils will be more likely to allow the bearing rolling elements make metal to metal contact resulting in spalling of the races or rolling elements. This condition gets worse as bearings wear and internal clearances increase.

You can think of it as hydro-planing your truck while driving on the road. Would it be easier to get your truck to hydro-plane while driving on a road covered water or maple syrup? Gears and bearings want to hydro-plane in their oil and not make metal to metal contact with their mating parts.

I would agree with SWMolines as to the viscosity needed ---use the Original type oil -- NOT Hy Tran or the like. They should give you the "long life" that MM engines and tractors were known for.
When I worked at MM there were very few or any thing other than Power steering or automatic transmission oil that were similar to Hy -Tran. We used these fluids in the spark plug hole to "unstick" "frozen engines and similar rust parts.

Still looking for the trans filter. Does anyone have the filter part number?

My Vista parts list shows a 20P3339 and that crosses to Wix 51567, most NAPA numbers just drop the first number or NAPA 1567.
bRYCE

(quoted from post at 00:04:30 07/14/15) My Vista parts list shows a 20P3339 and that crosses to Wix 51567, most NAPA numbers just drop the first number or NAPA 1567.
bRYCE

Click to expand...

I think the filter he is looking for is the one inside the rear differential and is accessible through a cover in the bottom of the rear differential case.

Ok, so it appears the non vista G1000 does not have an external filter, just the internal screen mesh around the pickup. So we started changing the oil and ran into a "issue" we had checked the oil level and it was up to the sight plug. It was milky but it was there. We started draining the rear and got a lot of water/crud/oil. But the odd thing is we only drained about 10 gallons of liquid. And the manual calls for 22 gallons of oil. This seemed odd since the sight plug showed it was full.

So we decided to start the flush and put 12 gallon's of diesel fuel in to the diff/trans. This did not even show up on the sight plug. You can look down in the fill hole and see the diesel sloshing around.

So we are a bit stumped on why the oil showed up at the sight plug, but were only able to drain about 10 gallons of liquid out. Then when putting 12 gallons of diesel in we still do not show it as full. Anyone run into anything like this before?

Thanks,
Ryan

Just a thought, are you sure you have the proper sight plug?

Well they are the only sight plugs on the right side of the tranny/gearcase. We proceeded putting the gear oil in as we could not find any other issues. Manual calls for 22 gallons, that brought us up to the bottom sight plug. put in another 2 gallons and it still is not up to the top sight plug.

Also with this we are starting to get some oil seeping from the brake drum case which we did not have before, and this is an even thicker oil than what was taken out.

Anyone else run into issues like this? Since we are at least at the lower sight plug we have been running the tractor a bit to see if anything changes. Any thoughts?

Thanks,
Ryan

You are over full. That thinner oil is probably diesel left in the system from flushing, floating on top of the gear oil. The 22 gal you put in to reach the lower plug is the correct level. The upper plug is the level for the Ampli-Torque Review pages 8 & 9 in Manual S430B If you did not drain the front compartment picture Page 10. It is still full of crappie fluid. Two separate compartments, but they mix read your manual thoroughly fluid is pumped to the upper level and drains back to the trans through the bearing on the upper shaft.
MMDEL