BX2670 HST Overheat

[overkill]

Hi Folks - Looking for some guidance for an overheat situation with my HST. I have a 2016 BX2670-1 with about 48 hours on it. At hour 44, I performed the 50 hour service and changed the HST filter replacing with a OEM Kubota filter, and also cleaned the HST screen. I overfilled the HST (accidentally) to about 5/8 inch above the full mark on the dipstick. Between hour 44 and 48, I bush hogged (using a 42inch land pride cutter) a heavily overgrown field with hills, requiring 4wd most of the time. The temp gauge never went over 3 bars. All of this work was done in low gear and between 3000-3200 rpm. I worked for an hour, took a break for 30 mins, and then work for over 2 hours nonstop. This was the hardest I have ever worked the tractor. In the second mowing session, the transmission got extremely hot and exhibited the following symptoms:

While I was mowing, the cutter kept dropping and I would have to raise it up periodically.

The transmission has noticeably louder at idle than it was before I hogged.

At idle, it would not lift the cutter off the ground. I had to raise the rpms to 2000 to lift the cutter. Prior to the 2 hr session, it would raise cutter fine at idle.

When I was raising and lowering the cutter while mowing, the transmission made a noise I had never heard before, kind of a squirting noise.

The FEL and steering continued to operate as normal.

After letting the mower cool off for 2 hours, the noise abated and the raising and lowering of the cutter seemed to work as before. I didnt run it enough to really do a comparison as I didnt want to mess it up more. I didn't really realize that things were not as normal until after I stopped mowing and started thinking about it. Had a job to do and was in the zone...

I now am in the middle of draining the HST fluid (factory fill) and replacing with UDT2. I am also replacing HST filter with another OEM Kutoba filter. I also cleaned the HST screen, and am attaching photos of the screen. These filings are from approx 3.5 hrs of (extremely hard) use.

So my question is did overheating the transmission permanently damage it? If so how can I diagnose the damage, or should I take it to the dealer? Anything to watch for? What are the chances that overheating it will cause it to fail down the line? Basically I am looking for some help in better understanding if I have screwed up my beloved tractor, and to what degree. Thanks for any and all help.

 

[Dave_eng]

Can you advise on the proper quantity of UDT fluid compared to the amount you accidentally put in.

5/8" over mark is not very telling except to someone who has the same machine. I am looking to see did you overfill by 50% or by 10%.

Human touch is not a good judge of what is hot to a machine. 130F will feel very hot to a hand but to a machine, it is not even hot enough to boil off condensation.

You might consider getting an infrared temp gun which are available for $20 to $30 and in that way you have real numbers to judge if something is hot.
https://www.amazon.com/Etekcity-Las...er/dp/B00DMI632G/ref=sr_1_1?ie=UTF8&qid=15025

Dave M7040

 

[Grouse Feathers]

I don't know how heavy your mower is, but it is normal to increase the engine speed to raise heavy 3 point implements. The hydraulic pump is positive displacement so pump capacity is directly related to speed. The rated pump capacity of 6.2 gpm is probably at rated speed of 3200 rpm. In addition it is normal for the 3 point hitch on a BX to sag down with a heavy implement. When using a the fel and a rear counter weight I have to constantly raise the counter weight.
As Dave said, buy an infrared heat gun the temperature of the hydrostatic transmission probably gets over 190 degrees. If you do suspect overheating of the transmission be sure to check the hydrostatic cooling fan. Look underneath the tractor below the seat. If you are mowing down shrubs and small trees you should probably be investing in additional protection for the fan like this: http://bxpanded.com/under-armor
Your particles on the screen look like normal machining residual not damage. So replacing the fluid may be overkill.

 

[overkill]

Thank you for your responses guys.

I think it was approx 1-1.5 quart overfull. Total system capacity is 3.1 gallons. When I changed the HST filter it was reading low and then after I ran it it read high.

I do have an infrared heat gun but didn't read about that being a way to measure trans temps until after this incident. Will have it with me from now on.

The cutter weighs about 400 lbs. Its the first time that I have used a piece of equipment on the 3 pt hitch, so its helpful to know they tend to droop over time.

The HST fan is fully intact with all blades accounted for. The tractor has a fan shield from the factory; I don't know if that's something that was added to BXs in recent years or not. Is the BXpanded one still recommended in addition to the factory one, or is that for older tractors that don't have a shield?

Finally, good to know the screen only had normal residual machining particles on it. My calculus on changing the oil is that since it overheated, the viscosity likely changed (accounting for the increased noise) and the oil has broken down. 80 bucks of oil is not the end of the world.

Any other input welcome!

 

[Grouse Feathers]

If you are going to be operating in brushy areas or in the woods with limbs and twigs on the ground a brush guard in good insurance. It should protect not only the fan, also the hydrostatic filter, fuel filter and wiring. Bxpanded and Bro-tek are the most popular guards, or you can build your own.
400# is definitely enough weight to sag the 3 point on a BX and one of the biggest complaints of owners you use 3 point equipment on a BX. The 3 point position control on the larger tractors will hold 3 point equipment at the set elevation while the tractor is running.

 

[Dave_eng]

Thank you for your responses guys.

I think it was approx 1-1.5 quart overfull. Total system capacity is 3.1 gallons. When I changed the HST filter it was reading low and then after I ran it it read high.

I do have an infrared heat gun but didn't read about that being a way to measure trans temps until after this incident. Will have it with me from now on.

The cutter weighs about 400 lbs. Its the first time that I have used a piece of equipment on the 3 pt hitch, so its helpful to know they tend to droop over time.

The HST fan is fully intact with all blades accounted for. The tractor has a fan shield from the factory; I don't know if that's something that was added to BXs in recent years or not. Is the BXpanded one still recommended in addition to the factory one, or is that for older tractors that don't have a shield?

Finally, good to know the screen only had normal residual machining particles on it. My calculus on changing the oil is that since it overheated, the viscosity likely changed (accounting for the increased noise) and the oil has broken down. 80 bucks of oil is not the end of the world.

Any other input welcome!

The amount of over fill is not significant and would not cause serious problems in the time frame you mentioned. Consider what happens when your machine is going up or down steep slopes, the oil will all be at one end or the other and the machine tolerates that without a problem.

My personal experience is that when I think I have been hard on a machine I begin to hear all sorts of noises which my brain amplifies. In reality, nothing has changed except you feel a little guilty for being too hard on it and thus more attentive.

You have a tough machine. It will continue to serve you well. If Kubota felt that trans temps were critical, they would have provided an electrical dash display. Likely they can get hot enough to fry an egg and not have problems. Modern lubricants are truly amazing.

Dave M7040

 

[RCW]

I'm with the other guys. I think they both gave great advice.

A quart over isn't great, but that 5/8" is in the narrow "neck" of the HST housing for the stick. I believe a non-issue, and honestly, doubt it's even a quart over for that 5/8"....

The HST fan is an issue if damaged. Get a plate to protect it, as they said. I just got a BXPanded one this year for my 4 year old BX2360.

An HST does run hot by design, but you don't want too hot, thus the IR thermometer. Somewhere recently I think someone recited typical temperatures. If the SUDT2 came out smelling burnt or chunky, different story.......but if it came out clear and of normal color, you're set. Honestly, you probably threw away perfectly good fluid, but I would have done the same thing if I got spooked about it!![emoji41][emoji609]

You should NOT operate the hydraulics at idle, especially a 400 pound cutter on the 3ph. RPM's are your friend there. That can cause problems down the road.

Long story, but I think you're fine. The additional stuff in the screen is simply extra stuff churned up by the heavy work on a machine that new.

Keep an eye on it, but I am willing to bet you're okay.
Good luck!![emoji106]


Sent from my iPhone using Tapatalk

 

[JackJ]

I started a thread in April 2016 about HST temperatures and I'm still looking to find out how hot is too hot. Both my dealer and I contacted Kubota, but they don't publish a specification and were moot on the question of what is the upper limit for safe operation.

Using an infrared gun I've seen temps as high as 222F on my HST, measured as described in this post:
http://www.orangetractortalks.com/forums/showpost.php?p=187744&postcount=17

"Normal" temp is often given as ambient +100F, and that's pretty typical for me when the tractor has been running a while and not being put to serious work mowing. Would love to see what temps other BX owners see under hard use conditions on hot summer days.

Jack

 

[overkill]

Thanks for your responses everyone. I appreciate the reassurance and advice.

As far as temps, I'll take readings the next time I work it hard and post it on the link that JackJ references.

 

[Dannymax]

Overkill, your screen looked like my BX2680 screen at 113 hours. If you have concerns draw a magnet over the particles and see if any are ferrous based...my guess is they are aluminum.

As others have said, the 5/8" overfill is insignificant and likely no more than 6 - 8 ounces.

 

[whitetiger]

Overkill, your screen looked like my BX2680 screen at 113 hours. If you have concerns draw a magnet over the particles and see if any are ferrous based...my guess is they are aluminum.

As others have said, the 5/8" overfill is insignificant and likely no more than 6 - 8 ounces.

The post you responded to is over 7 years old and the original poster has not been on here for over two years. he probably has it worked out by now.

 

[Dannymax]

The post you responded to is over 7 years old and the original poster has not been on here for over two years. he probably has it worked out by now.

Didn't notice that...sorry.

 

[WI_Hedgehog]

Meh, good reading for the noobs like myself.