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Komatsu D65E-6 transmission overheating issue found, need advice

A

ATCme

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Aug 24, 2015
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bc
After battling an over heating torque convertor issue on my dozer for the better part of a year and without throwing parts at it except gaskets and orings we have finally found out why it gets hot. The forward first gear clutch leaks internally in the transmission bypassing the oil cooler.
I'm at at crossroads with this dozer now and have three options
1--Sell it and find another one and cut my losses
2--Buy another one without a winch and use the D65 in short bursts to pull logs since i need at least one with a winch
3--Or keep it and fix the transmission. My problem is will this cost me more than just cutting my losses and finding a new one? Should i go the extra mile and rebuild the torque convertor as well?

Just looking for what others have to say about it. I haven't advertised it or even put a price tag on it at this point.
 
John C.

John C.

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You might look into parts availability first. I've been hearing that Komatsu has started to abandon some of their older models.
 
A

ATCme

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bc
You are right. Can't get clutch pack anymore. In order to fix what went wrong i need at least the forward set. From what my mechanic said the piston has overextended and blown out a seal. I'm looking for a used transmission as well but so far no such luck.
 
C

Clod kicker

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Oct 8, 2015
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I'd also like to take up the D65-6 transmission problem.
"Converter Oil" guage rising over 135 degrees C.
Recently Cummins 220 engine overhauled, plus new sprockets and plates- I raise this in the context of increased horsepower and increased traction may be adding to pressure on the torque converter?
For some reason transmission oil was considerably over full(not from Hydraulic nor engine), have reduced and this prolonged the period it took to overheat. Tomorrow I will reduce level further until the oil is only just over full(working on steep country).Oil is Castrol TFC 430 as recommended, in good order.
Can anyone throw "light" on the subject or am I destined to "nurse" the old girl! 135 degrees is out of the operating range, and presumeably damaging to oil
 
C

Clod kicker

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Joined
Oct 8, 2015
Messages
7
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Australia
ATCme said:
After battling an over heating torque convertor issue on my dozer for the better part of a year and without throwing parts at it except gaskets and orings we have finally found out why it gets hot. The forward first gear clutch leaks internally in the transmission bypassing the oil cooler.
I'm at at crossroads with this dozer now and have three options
1--Sell it and find another one and cut my losses
2--Buy another one without a winch and use the D65 in short bursts to pull logs since i need at least one with a winch
3--Or keep it and fix the transmission. My problem is will this cost me more than just cutting my losses and finding a new one? Should i go the extra mile and rebuild the torque convertor as well?

Just looking for what others have to say about it. I haven't advertised it or even put a price tag on it at this point.
Click to expand...
ATCme, have just posted text under "Clod kicker" re Komatsu 65-6 .
IF our machine has the same problem as yours, what is the process of elimination to identify the exact cause.
Any help would be greatly appreciated.
 
A

ATCme

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Aug 24, 2015
Messages
113
Location
bc
Clod kicker said:
ATCme, have just posted text under "Clod kicker" re Komatsu 65-6 .
IF our machine has the same problem as yours, what is the process of elimination to identify the exact cause.
Any help would be greatly appreciated.
Click to expand...

I can only tell you what i went through to get to where i am. It may not have been the right way but it was certainly better than the "throw parts and see what sticks" way.

My first sign of a problem was a lot of clutch material in the bottom of the transmission, and i mean a lot. I will post a picture if i can find it. Both my strainers and filters weren't catching it. It just kind of stuck to the bottom of the transmission. Taking out the T/C and transmission strainers i was able to make a scraper to pull all the excess gunk out. I filled it back up with fluid and that was it. The second sign was it overheating only on the T/C, the engine has always run within operating temp. I walked the dozer over 6 kms in second and first gear to get it to my work site. I kept having to pull over and let it sit in neutral at full rpm to cool down. Putting it at idle speed made it heat up even more. At this point i thought my T/C was done. Called in my mechanic and he fixed a lot of other issues with it first before tackling the overheating issue. I only needed it to push over piles of road material in short bursts but in the future i wanted to do some forest clearing to make some fields but could only get a few turns in before the gauge hit the red line. The first order was to see of the cooler was working and not clogged. Took it all apart and it was clean as a whistle. Next was to see if the T/C was leaking an excess of fluid. Took the plug off after hard use and minimal fluid came out which is what you want to see, too much and the T/C builds up heat running thru all the excess fluid in the case. Third check was just a hail mary to see if the valve control may have been leaking but first my mechanic checked the pump pressures in all gears. There is a way to test it and it is in the manual and i am no expert on explaining how he did it but it proved my pumps were making enough pressure. Once we had the valve control off he used his shop air to engage each gear. In reverse everything was quiet but when he engaged forward you could hear it hissing internally. Engaging first was the worst. All that clutch material now made sense. It only cooling down when at full rpm made sense, at idle no fluid was going to the cooler.
 
E

epirbalex

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ATCme said:
You are right. Can't get clutch pack anymore. In order to fix what went wrong i need at least the forward set. From what my mechanic said the piston has overextended and blown out a seal. I'm looking for a used transmission as well but so far no such luck.
Click to expand...
I had a look at my 155 workshop manual and all clutcp packs look much the same , could you use 3 foward or 3 reverse plates to rebuild 1 st foward .
 
A

ATCme

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epirbalex said:
I had a look at my 155 workshop manual and all clutcp packs look much the same , could you use 3 foward or 3 reverse plates to rebuild 1 st foward .
Click to expand...
I was able to find a few aftermarket kits plus two Komatsu Genuine overhaul kits. I'm just waiting for a parts breakdown of the cheaper kits. Only 285$ seems awfully cheap.
 
A

ATCme

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Here's the picture of my transmission strainer removed and the goo that came out of it. The goo was over an inch deep in the bottom of the case. At the time we thought it was causing a sluggish start to the dozer by choking off the strainer. Also none of the goo contained any steel chunks or filings only aluminum, bronze and brass.
 

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E

epirbalex

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ATCme said:
I was able to find a few aftermarket kits plus two Komatsu Genuine overhaul kits. I'm just waiting for a parts breakdown of the cheaper kits. Only 285$ seems awfully cheap.
Click to expand...
Good to see ,-6 too good to walk away from .
 
A

ATCme

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epirbalex said:
Good to see ,-6 too good to walk away from .
Click to expand...
Yes indeed. Way too reliable. Way too simple. Zero electronics. I would say better built than a D6 of the era (don't shoot me). The downside is parts and the cost.
 
E

epirbalex

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Komatsu very popular here with good backup . Caterpillar shaft us for parts , about a third more than Aussi . I would suspect you could rebuild your motor out of petty change compared to a D6 of the same age , would here anyway .
 
T

tctractors

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Pressure Test port is best to use the plug location in the Filter top lid, all the wear parts a still able to be located for the Transmission, the Torque will also need stripping, you need to be fitting new bearings in this, look for the 2 >< marks on the thrust bearing as these have to be facing each other on assembly, there is NO special tools needed to work on these units just a few small spanners, C'Clip pliers and a Hammer. tctractors
 
C

Clod kicker

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Messages
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ATCme said:
I can only tell you what i went through to get to where i am. It may not have been the right way but it was certainly better than the "throw parts and see what sticks" way.

My first sign of a problem was a lot of clutch material in the bottom of the transmission, and i mean a lot. I will post a picture if i can find it. Both my strainers and filters weren't catching it. It just kind of stuck to the bottom of the transmission. Taking out the T/C and transmission strainers i was able to make a scraper to pull all the excess gunk out. I filled it back up with fluid and that was it. The second sign was it overheating only on the T/C, the engine has always run within operating temp. I walked the dozer over 6 kms in second and first gear to get it to my work site. I kept having to pull over and let it sit in neutral at full rpm to cool down. Putting it at idle speed made it heat up even more. At this point i thought my T/C was done. Called in my mechanic and he fixed a lot of other issues with it first before tackling the overheating issue. I only needed it to push over piles of road material in short bursts but in the future i wanted to do some forest clearing to make some fields but could only get a few turns in before the gauge hit the red line. The first order was to see of the cooler was working and not clogged. Took it all apart and it was clean as a whistle. Next was to see if the T/C was leaking an excess of fluid. Took the plug off after hard use and minimal fluid came out which is what you want to see, too much and the T/C builds up heat running thru all the excess fluid in the case. Third check was just a hail mary to see if the valve control may have been leaking but first my mechanic checked the pump pressures in all gears. There is a way to test it and it is in the manual and i am no expert on explaining how he did it but it proved my pumps were making enough pressure. Once we had the valve control off he used his shop air to engage each gear. In reverse everything was quiet but when he engaged forward you could hear it hissing internally. Engaging first was the worst. All that clutch material now made sense. It only cooling down when at full rpm made sense, at idle no fluid was going to the cooler.
Click to expand...

ATCme said:
I can only tell you what i went through to get to where i am. It may not have been the right way but it was certainly better than the "throw parts and see what sticks" way.

My first sign of a problem was a lot of clutch material in the bottom of the transmission, and i mean a lot. I will post a picture if i can find it. Both my strainers and filters weren't catching it. It just kind of stuck to the bottom of the transmission. Taking out the T/C and transmission strainers i was able to make a scraper to pull all the excess gunk out. I filled it back up with fluid and that was it. The second sign was it overheating only on the T/C, the engine has always run within operating temp. I walked the dozer over 6 kms in second and first gear to get it to my work site. I kept having to pull over and let it sit in neutral at full rpm to cool down. Putting it at idle speed made it heat up even more. At this point i thought my T/C was done. Called in my mechanic and he fixed a lot of other issues with it first before tackling the overheating issue. I only needed it to push over piles of road material in short bursts but in the future i wanted to do some forest clearing to make some fields but could only get a few turns in before the gauge hit the red line. The first order was to see of the cooler was working and not clogged. Took it all apart and it was clean as a whistle. Next was to see if the T/C was leaking an excess of fluid. Took the plug off after hard use and minimal fluid came out which is what you want to see, too much and the T/C builds up heat running thru all the excess fluid in the case. Third check was just a hail mary to see if the valve control may have been leaking but first my mechanic checked the pump pressures in all gears. There is a way to test it and it is in the manual and i am no expert on explaining how he did it but it proved my pumps were making enough pressure. Once we had the valve control off he used his shop air to engage each gear. In reverse everything was quiet but when he engaged forward you could hear it hissing internally. Engaging first was the worst. All that clutch material now made sense. It only cooling down when at full rpm made sense, at idle no fluid was going to the cooler.
Click to expand...

ATCme, many thanks for your reply to Clod Kicker.
Been away from computer up in some steep country on dozer,thus slow reply.
Proceeded to drain both TC oil(only a small amount) plus transmission oil. Both oils in very good order and both screens carrying a normal amount of trash(no metal filings or water).Refilled to just very slightly over full.
Temp guage mid operating range and then sometime later rose 135 degrees C plus - very disappointed. Was it the guage/sender unit? When the guage said it was hot , the incoming and outgoing pipes to the water cooling unit were not unbearably hot. Removed the guage and sender unit and ordered a new outfit. Tested old unit three times over a period of time, in boiling water- returned to the same mark each time.
Will install new unit just after Christmas, but am still not happy(!) If there is something amiss why doesn't the oil change colour, smell hot or pipes unbearable?
Clod Kicker
 
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ATCme

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20$ temperature gun was way cheaper than a 200$ Komatsu gauge. My oil never looked or smelled bad after the first oil change. I would be more worried about the seals and clutches getting damaged before the oil goes bad. The oil can probably take the higher temperature for longer, but the internal seals would harden shrink and crack from the excessive heat. Someone else can chime in on that, like i said i'm no expert on any of this.
 
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tctractors

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The D65-6 Torqflow Transmission has common seals and plates on Forward, Reverse,2nd and 3rd Clutch units, the 1st Speed unit is different with the large dome type washer, the cheep O ring kits do NOT contain the Clutch piston seals, I think the seal kit you are looking at is 144-15-22871 and 881, the Transmission Pump is a common unit used on loads of Komatsu Iron including the D85P-18 and the D95S-2 Shovel the Part N'o is FAL040, you can still get the parts for these Transmissions, the other thing to look out for is the injector set as it's very low at 55 "lbs. tctractors
 
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ATCme

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Bit the bullet and pulled the tranmission. 1300 lbs of fun.
 

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ATCme

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The pinion has a small chunk taken out of it. Is this worth worrying about? It's not directly in the face of the tooth. Finding a replacement pinion might be a problem.
 

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ATCme

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The question is should I do the TC as well? If it is a strong yes then do these overhaul kits come with TC parts as well? What kit manufacturers should I be using overall?
 
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