Foam in VAC transmission

Lee_K

Member
What causes foam in a gear case? I had this problem once before and I thought it was water in the oil but I don't think that is true. This tractor has never sat outside or been hosed off since the transmission oil was changed. It has harvest king 85w 90 in it now. I realize this is not the best oil on the market but I wouldn't expect it to foam like this. Any help is much appreciated.

Thanks,
Lee
 
How do you know it is foaming? Is it coming out somewhere?

Does the tractor have hydraulics? Foam can be caused by air being sucked in on the suction line to the hydraulic pump. Then when the oil ends up in the reservoir (transmission case) the foam becomes evident. Suction line could have a loose clamp, failed hose (pin holes), broken suction tube, failed pump seal, etc.

It could be the hydraulic/transmission fluid being used???
 
The torque tube is the hydraulic oil reservoir, that is separate from the transmission sump. The only way the hydraulic oil can get into the transmission sump is through a leak in the front of the transmission like the drive shaft seal. Anyway you can check the hydraulic oil at the fill plug.

Let the tractor set a couple days and then crack the drain plug, if the oil is water entrained you will get some free water.

One drain and refill of the transmission is not going to get rid of all the emulsified oil. Partly because you are not going to get all the contaminated oil out that is adhering to the casing & running gear. Also VAC has flooded axles and it is necessary to jack up each side of the tractor in turn to ensure the axles are fully drained. We used to drain and make a short run with a few gals of kerosene to flush the transmission.

You can use thieving paste to check for water. Smear some on a stick and run it to the bottom of the transmission for a few seconds and pull it right back out. Water entrained oil will show up as speckles and free water will change the paste color to a definite level.

Joe
 

There were bubbles half way up the dipstick today when I checked the oil. This was after driving around a while. I guess you would call it foam, but I know it is not good.

I have changed the oil twice since I got the tractor back in January. The first time I put used motor oil in and ran it for a short time then put in fresh oil. The second time I just replaced the oil. I did not know about tipping the tractor to get the oil out of the axles (i guess you learn something new every day) .
I will check for moisture at the bottom in day or two. I will also order water finding pate and give that a try.

It looks like I will probably have to change the oil again. I assume 85W - 90 is correct. I know hytran is slightly cheaper, it seems some people have suggested that somewhere along the way.


Thanks for your help so far,
Lee
 
Thieving is marine speak. When you bunker a ship the fuel tanks are thieved for water via the sounding tube, hence the name thieving paste. Jars like the pic are avail on Amazon, a little goes a long way.

85w90 is fine for the transmission, don't know about the brand you mentioned. Sounds like you got somewhat of a flush already. Does the foam disappear after the tractor sits for a couple hours, emulsified oil will remain milky.

Joe
cvphoto44587.jpg
 

The foam or bubbles seem to go away after some time. Friday after driving it the oil at the drain looked like it had some fine bubbles too. But this morning I cracked the drain again the oil looked normal. I will try to post a picture. Harvest King is Rural King's store brand. I have some paste ordered. It is supposed to be in Monday.

Also dumb question, should you check the oil level with the dip stick screwed in or just set on top? I know improper level can cause foam also.
 

The tractor has been sitting since Friday about noon. Here are a couple pictures from the top and some oil collected from the bottom. The oil does not look as good as I expected but I've never really examined oil that close before.
mvphoto46577.jpg



mvphoto46578.jpg
 
Looks to me like it has some sludge build up in the bottom of the transmission that being picked up by your new oil. Maybe someone else can offer a different opinion.

If it was mine I would drive it around for awhile and then drop the oil, don't forget the axles. When drained stick your finger in the drain hole and feel around for sludge, it may be fairly clean right in that area due to oil erosion so if there is sludge there will likely be heavier deposit elsewhere. I would also pull the shifter cover and look at what is visible of the floor of the casing.

Years ago we used kerosene for flush, some people here recommended diesel awhile back. I don't know what flush is best.

Transmission oil level is checked with the dipstick threaded all the way in. Just set the plug on the opening and substract the visible level up to the full mark equal to the length of the threads.

If you pull the shifter cover have it in neutral and pull straight up. Take your time and look at the location of the shift collars, better yet take a pic, you're going to need them back in the same position when replacing the cover so the forks are properly engaged.

Joe
 
Lee,personally I would pour in a couple gallons of diesel fuelwith the oil and run it a while to break up the sluge build up.then change it again.in my mind I think it's easier on the old seals,I may not be right on that theory but I personally have had good results this way on older equipment.and as already stated,don't forget the axle tubes. If possible drive it on a hill side ,that will be sure to at least get the tube oil mixed..clint
 
I will plan to flush and change the oil the next chance I get. Will this fix the original problem of foam? Also there are some oil additives I found today at the store. Would the foam problem benefit from something like hy-per lube oil supplement.

Thanks again
Lee
 
Lee I think you're jumping the gun with oil additives. Wait until you have flushed and checked out the condition of new oil. I would certainly pull the shifter cover while the transmission is drained and see if any obvious anomaly can be spotted.

Hang in there and remember the Case Tractor Owners Motto ..........

Joe
cvphoto44793.jpg
 

Okay thanks! I will have to get some oil and diesel this week. I will let you know how it goes.

Thanks,
Lee
 
Please do,you would probably never believe some of the things that have been found in old tractors trans ,engines, rears.that would be a good topic ,lol
Clint
 

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