M4700DT PTO Shaft seems too Hot

[TK4700DT]

Hello everyone, I am a new guy to the site and have a question I hope someone can help me with. I purchased my Used Kubota M4700DT last fall with 1000hrs, Changed all fluids and oil/filters(Kubota filters/Fluid). I had noticed that after using it with a 6ft finish mower the PTO shaft seemed very warm but after using it to Bush Hog yesterday for about 4hrs, it seem too hot. I was unhooking the bush hog and the BHs PTO shaft was too hot to keep my hand on it. I then sprayed off the grass from the PTO area and that area along with the axel housing was too warm. I don't want to say the water steamed but it did dry off very quickly. After I put it up for a couple of hours I check the Hydraulic Fluid level and it was at the top mark. Does anyone have an idea of why it would be hot, should I be worried? Well, I guess more worried! I would appreciate any advice.

 

[Bulldog]

What kind of fluid did you use when it was changed?

 

[TK4700DT]

Hello Bulldog, I used the recommended Kubota Super UDT. This is really bugging me, I would not think it would get that Hot, it runs smooth as silk, you cant hear anything when engaging the PTO, no leaks, no vibration.

 

[Dave_eng]

I think you are worrying needlessly.
To the human hand 130 F feels very hot.
Coolant and lubricants are designed to run hot.
For example, the cooling system in a modern car is designed to run around 200F.
There is sometimes an automatic transmission cooler located in the header tank of the car or truck's radiator. If it is going to be cooled by 200F coolant it is obviously running much higher than 200 f.
Kubota's big concern is people operating their tractors in cold weather without letting them run at high idle for up to 20 minutes just to ensure the transmission fluid is warm enough.
Dave M7040

 

[TK4700DT]

I think you are worrying needlessly.
To the human hand 130 F feels very hot.
Coolant and lubricants are designed to run hot.
For example, the cooling system in a modern car is designed to run around 200F.
There is sometimes an automatic transmission cooler located in the header tank of the car or truck's radiator. If it is going to be cooled by 200F coolant it is obviously running much higher than 200 f.
Kubota's big concern is people operating their tractors in cold weather without letting them run at high idle for up to 20 minutes just to ensure the transmission fluid is warm enough.
Dave M7040

Dave, I sure hope you are correct. I've been a farm guy all of my life, (Not farming now, mostly upkeep, hobbies and food plots) just never seen my equipment PTO shaft too hot to handle. If I can get my hands on a temp gun, what would be a Concerning Temperature?
I hope to get some pics today for you guys, I've had the B6100E for about 20 yrs then last year, finally got the 4 wheel drive I've always wanted so I want to make sure it stays in good shape.

 

[Dave_eng]

To help ease your concern look at the maximum temperature on the dials of the transmission oil temperature gauges in the following link.
http://www.glowshiftdirect.com/transmission-temperature-gauges.aspx

Kubota and other more modern tractors are built with far less weight, i.e. lighter castings, than tractors from the 1950's and 1960's. The heavy weight of the earlier absorbed temperature fluctuations when operating at high loads. It was a bit of a heat sink which is not part of modern tractor design.

Dave M7040

 

[TK4700DT]

Added a couple pics to my profile

 

[Bulldog]

Hello Bulldog, I used the recommended Kubota Super UDT. This is really bugging me, I would not think it would get that Hot, it runs smooth as silk, you cant hear anything when engaging the PTO, no leaks, no vibration.

Heat will transfer from the tractor thru the pto shaft and if you touch it right after work it will be pretty warm. I suggest getting a IR heat gun and see exactly what kind of temps you're dealing with. Like what Dave said it probably nothing to worry about. Is it just hot to the touch or does it burn a blister? If it's hot enough to burn you then you have a problem. Warm, probably just fine.

I just came in from a 6 hr mow and the tractor had set for about 10 minutes.
The pto coupler was 107* and the case where the pto shaft comes out of the tractor was at 138* if that helps you.

 

[TK4700DT]

Heat will transfer from the tractor thru the pto shaft and if you touch it right after work it will be pretty warm. I suggest getting a IR heat gun and see exactly what kind of temps you're dealing with. Like what Dave said it probably nothing to worry about. Is it just hot to the touch or does it burn a blister? If it's hot enough to burn you then you have a problem. Warm, probably just fine.

I just came in from a 6 hr mow and the tractor had set for about 10 minutes.
The pto coupler was 107* and the case where the pto shaft comes out of the tractor was at 138* if that helps you.

Thanks, I will try to locate a heat gun to check.

 

[TK4700DT]

Well Guys, my mower is 2 yrs old and I like to grease......but the heat is coming from the front u-joint of the mower, actually 1 cup. The Infrared Thermometer is Awesome!!

 

[Dave_eng]

Interesting find with the one cup being hotter.
Now you will start driving yourself nuts with the wealth of data you are going to accumulatehttp://www.orangetractortalks.com/forums/images/icons/icon7.gif
Remember with the heat gun, that the color and type of surface affect a property called emissivity so be certain all cups are clean to get true comparative numbers. If one cup had a smear of dark grease on it it would appear hotter to the gun.

Dave M7040

 

[TK4700DT]

My thinking is that the one was setting in a position, before I came along to purchase, taking in more weather than the other.
I will replace both Front and rear.
Thanks for everyone's help!

 

[TK4700DT]

I would never thought this could have been the problem... If I attached the pic hopefully you can see, the yoke bore is actually off center.

 

[North Idaho Wolfman]

Looks to me like the yoke is bent on the other side?

Regardless of the issue, changing it should help!

 

[Diydave]

Damage like that could come from shipping, handling, over torquing with a high HP tractor, or just bad QC, at the factory. Them IR thermometers sure is the bee's knees at finding all sorts of problems. Usedta cost around $300, saw an ad last week, for $19!

 

[Bulldog]

I would never thought this could have been the problem... If I attached the pic hopefully you can see, the yoke bore is actually off center.

I just found one just like that on my batwing. I went to TSC and they didn't even come close to having one big enough so it was off to the driveline shop. After talking to those guys bent or twisted yokes are a very common issue. They said the yoke is one of the first weak links purposely made that way to help save the drive shaft. Like the man said, would you rather spend $50 for a yoke or $300 for a drive shaft.