1626 Front axle oil change mixed info??

[Flexwing man]

Anybody have the correct procedure on changing the front axle oil on the Mahindra 1626? I'm guessing this is similar to other models as well.
This is what I know based on what Mahindra USA has told me:
Oil type should be Mahindra Hydraulic fluid, not gear oil.
Here is where I've gotten different answers from different dealers as well as Mahindra:
I know there are 3 points to drain the axle, one in the middle and one under each gear case on the right and left ends of the axle.
One fill cap on top of the axle just to the left of center when looking at the front of the tractor.
The book says when when filling the axle up you should remove the two bolts on the top back sides of the gear cases to let the air out. Oil should come out of these two vent holes. These vent holes would keep it from having an air pocket. These two vent plugs are a 12mm bolt head size.

When I added oil to my axle, oil never would come out of these vent holes. Even after running the tractor around a field a couple of times and pulling the two bolts the next day, no oil came out and the axle oil level was the same. I ended up using a pump type oil can to put some oil in through each vent hole.
One dealer told me that they only fill the axle and figure that oil will eventually work its way into the gear cases.
I'm not sure if oil will ever migrate into the gear cases, especially if the vent holes are never opened.
Anyone know or fully understand the correct method??

 

[RNeumann]

On typical axles the gear oil level is about 1/3 to 1/2 up the axle tubes. This is enough to get carrier bearings and axle bearings. The pinion bearings are lubed by splash from the ring and carrier. With the final drives on the tractor fluid flows down the axle tubes and into the final drives.

The majority of the fluid comes out when you pull the drain plug on the diff case. The final little bit would come out when you pull the drain plugs on the final drives.

To fill, you typically add fluid until it comes out the hole used to check fluid level......somewhere near the axle centerline.

Your term “vents” is a bit unsettling. If you filled the case until fluid was coming out the top you have overfilled it. That is where the vent would be. The bolts to remove are, as described above, somewhere near the axle centerline. Maybe one on the main case and one on each final drive. Otherwise just on the final drives.

The book should have a spec for fluid capacity. You should be close to that.

Using hydraulic fluid in a front end is fine. For extremely hot climates you could run gear oil. A tractor front end has an easy life from a lubrication stand point.

 

[Flexwing man]

Thanks for your info. The two vent bolts are on the top back sides of the final drives. Right now my oil level is about 1" down from the top of the fill hole. The manual calls for 4.2 qts , but I used 3150cc or 3.3 qts plus what I put in the final drives. Close to 4 qts. My manual actually shows a picture of the vent holes,(12mm bolt heads) and says oil should come out of them when filling the axle. My concern is that the oil doesn't come out of these holes or vents when filling the axle. Some dealers said they don't open the vent bolts at all and figure the oil will make its way into those final drives. I don't see how it can because of the air pocket in the top of them. When I drained them, they were full, maybe a half quart or more came out. I used the oil can/pump just to be sure some oil was in the final drives. I'll check the main axle oil level after more use to see if its dropped any over time. They say it should make it into the final drive. I just can't see it doing that having air trapped in the top of the final drives like that. I could just fill the final drive with the oil can and then adjust the oil level at the fill cap and call it good. The correct procedure for filling should be easier to find than it is.
Also, the reason I called a number of dealers and Mahindra was because there is no mention of any plugs to remove for the fill level. They just list the capacity at 4.2 qts. There are no fill level plugs that I can see. They might as well have a dip stick on the fill cap.

 

[RNeumann]

No oil comes out until it is full...that prevents overfilling. You have way over complicated this task. Pull the vent bolts (funny name to me). Add oil until oil comes out vent caps. You are done. The vent caps set the level.

 

[Flexwing man]

I know it sounds like I'm overthinking this, but no matter how much I fill the main axle through the fill cap, nothing comes out through the two vent caps? Have you actually had oil come out the vent caps when filling the axle?

 

[RNeumann]

I know it sounds like I'm overthinking this, but no matter how much I fill the main axle through the fill cap, nothing comes out through the two vent caps? Have you actually had oil come out the vent caps when filling the axle?

Yes! That’s when you stop filling...

Here is a video. Fast forward to about the 9:00 mark for the front axle.

Mahindra 1533/1538 50 hour service - YouTube

 

[johnsonauto]

I know it sounds like I'm overthinking this, but no matter how much I fill the main axle through the fill cap, nothing comes out through the two vent caps? Have you actually had oil come out the vent caps when filling the axle?

As said above, , fill until it runs out the vent plugs. It will take a while for this to happen FYI.

 

[5030]

Not that I own a Mahindra because I don't but I use 80-90 GL5 gear oil in both my Kubota's front axles because gear oil has a much better shock load capability than thinner hydraulic fluid and I use both mine in an ag setting.

 

[Flexwing man]

Keep in mind your entire transmission is being lubed with Hydro fluid with no issues. Your front axle as others have said lives an easy life compared to the main transmission and hydro fluid would be the choice is cold temps.

 

[Flexwing man]

I ended up just filling up both gear cases using a pump type oil can until oil came out. I then left the oil level at the fill cap 1" below the top. The only thing I didn't try was to fill the axle all the way up to the fill cap with the two vent plugs out. At 1" below the cap no oil was coming out the two vent plugs, even after 24 hours. I've not seen one video actually showing oil making its way out of the vent plugs. Not one dealer has told me the correct method to fill the front axle. None of them really seem to understand it. One dealer said he just fills it up to about 1.5" from the cap and never removes the vent caps. He figured it would eventually makes it way into the gear cases.
I may check mine one more time by pulling both vent plugs out and filling the axle up all the way slowly to see if it starts flowing out the vents. If it does, then my mistake, 1 inch from the fill cap won't do it. Thanks all for your input!