1940 Farmall B Transmission Leak

[KJB34269]

I have what I believe is transmission fluid leaking at the left wheel. You can see it in the first photo and the second photo shows where it is leaking from. I'm not too concerned about a leak in an old tractor but I don't want to do any damage either. I removed the level plug near the brake rod and I did get some slight dripping. That makes me think I have a sufficient amount of fluid in the transmission. I believe repairing the leak would be time consuming and costly. Any thoughts?

 

[grandpa Love]

Is the transmission overfull? If so the axle seal will leak. They are good at keeping debris out ,not great at keeping excess oil in. It's not going to hurt anything to drip.....but , open the "fill to here" plug and the fill plug on top of the transmission ( allows air in so it can drain) let the extra drain out. Unless you haven't changed that fluid for several years,then drain it all and refill. Between 4 and 5 quarts depending if you have a PTO and /or belt pulley.

 

[RedRamGT]

I have what I believe is transmission fluid leaking at the left wheel. You can see it in the first photo and the second photo shows where it is leaking from. I'm not too concerned about a leak in an old tractor but I don't want to do any damage either. I removed the level plug near the brake rod and I did get some slight dripping. That makes me think I have a sufficient amount of fluid in the transmission. I believe repairing the leak would be time consuming and costly. Any thoughts?

From the second picture, it looks like it is leaking at the upper seal on the final drive, where the transmission differential shaft goes into the final drive.

 

[Mrfred54]

To take care of this leak it would involve two seals. Inner axle and outer axle sealsc

 

[KJB34269]

Is the transmission overfull? If so the axle seal will leak. They are good at keeping debris out ,not great at keeping excess oil in. It's not going to hurt anything to drip.....but , open the "fill to here" plug and the fill plug on top of the transmission ( allows air in so it can drain) let the extra drain out. Unless you haven't changed that fluid for several years,then drain it all and refill. Between 4 and 5 quarts depending if you have a PTO and /or belt pulley.

Thanks, I will give that a try. I do have a belt pulley.

From the second picture, it looks like it is leaking at the upper seal on the final drive, where the transmission differential shaft goes into the final drive.

I did remove the fill plugs on both final drives and though nothing drains out, I can stick my finger in the hole and feel fluid.

 

[KJB34269]

To take care of this leak it would involve two seals. Inner axle and outer axle sealsc

Sounds like a big job for a novice. Am I correct?

 

[Jim Becker]

Sounds like a big job for a novice. Am I correct?

Big? Depends on who you ask. I wouldn't call it big, but I wouldn't do it without an overhead or engine hoist. Pull the tire/wheel disk off first. Then remove the final drive WITH THE AXLE EXTENSION ATTACHED. You have to remove the brake drum from the axle before removing the extension housing. Then you have both of the previously mentioned seals exposed.

 

[KJB34269]

Big? Depends on who you ask. I wouldn't call it big, but I wouldn't do it without an overhead or engine hoist. Pull the tire/wheel disk off first. Then remove the final drive WITH THE AXLE EXTENSION ATTACHED. You have to remove the brake drum from the axle before removing the extension housing. Then you have both of the previously mentioned seals exposed.

Thanks Jim. I do have an engine hoist so I'll give that some thought. I also have wheel weights.

 

[Jim Becker]

Thanks Jim. I do have an engine hoist so I'll give that some thought. I also have wheel weights.

From the first picture, it looks like you may have the heavy wheel option as well. Hopefully you don't have fluid in the tires too. I'd use the hoist to get the tire/wheel assembly off and out of the way. Then use it again on the final drive.

 

[grandpa Love]

From the first picture, it looks like you may have the heavy wheel option as well. Hopefully you don't have fluid in the tires too. I'd use the hoist to get the tire/wheel assembly off and out of the way. Then use it again on the final drive.

All that weight I might just live with it . Hopefully it's just overfull and draining down to the correct level will "fix" it

 

[560Dennis]

I don’t like gear oil on my tires , it rots sidewalls if left on there . Clean it off as soon as I see it.

 

[grandpa Love]

I don’t like gear oil on my tires , it rots sidewalls if left on there . Clean it off as soon as I see it.

I agree. But .... clean it off, check the fluid level ( if correct,it's nowhere near the seals) drain to correct level and it may never leak again.

 

[KJB34269]

I don't believe there is fluid in the tires. Big local parade tomorrow that we'll be in. We usually have anywhere from 30 to 50 tractors. Here's a photo from last year. I'll try Grandpa Love's draining down to correct level next week. Thanks for all the replies.

 

[560Dennis]

If you can clean all the oil off the surfaces then check it after the run to locate the source of leak . If it one of the bolts then ,I use permatex 2 on threads. To seal it and re torque. To spec.
I see what I think is a broken split washer under the bolt in photo ,thats not good . I see those on Farmalls in many places , cause from metal fatigue. 80 year old broken split washers are an issue when working that old machine. Can cause a lot of unnecessary damage to your machine. Check them all and correct , torque back up.

 

[Jim Becker]

I agree that any loose bolts or bolts with broken lock washers need to be taken care of. However, they (at least the ones holding the extension housing) will not be the source of a leak. If oil is getting past a bolt, the oil already leaked out to even get near the bolt.

If the transmission is overfull, there is a good chance it is because water has gotten in. I suggest starting at the drain plug. Carefully loosen it up and crack it open just enough to see what comes out. If water, let it dribble out until you start to get oil. Then go to the level plug and check for the proper level.

 

[KJB34269]

Thanks again for the replies. I may just drain it and start fresh. Then I know what and how much is in it. It's just 80/90 lube, right?

 

[grandpa Love]

Thanks again for the replies. I may just drain it and start fresh. Then I know what and how much is in it. It's just 80/90 lube, right?

That works. In the south we use 85-140.

 

[560Dennis]

Thanks again for the replies. I may just drain it and start fresh. Then I know what and how much is in it. It's just 80/90 lube, right?

Id use sae 90 gl1

 

[KJB34269]

Id use sae 90

I see TSC has that. I may pick some up.

 

[Jim Becker]

I see TSC has that. I may pick some up.

Make sure it is GL4 (or older), not GL5.