I have a 2006 980H with the converter temp getting hot. It hasn’t had a history gwtting warm, it just happened all of a sudden. The transmission functions normally with no slipping or shifting issues. I cut the filters open and they were clean. No debris at all, but the oil was dark and smelt burnt. It does come back down to normal operating temperature if I let it idle, but it takes a bit longer then it should. As soon as I get a few buckets back into the pile the temperature starts climbing quick. Any thoughts of where to look?
Post a machine Serial Number please. If the oil is dark something is slipping. Did you pull the suction screen/magnet assembly for inspection.? How long does the converter outlet temp take to come down if you run the engine at about hals-speed RPM in neutral.? Have you had pressure gauges on it yet.?
Serial: Jms01870 I have not checked pressures because I have no service manual and not sure what they should be. Temperature goes up to the red and comes back down to just above mid gauge after about a minute on idle. Had it parked on idle for about 5 before the gauge would go below half. My temperature gun was reading 195 at that time on bottom of the transmission case by the driveline. I haven’t pulled the suction, but as I said previously the transmission was pulling hard and not missing a beat. I was thinking the cooler might be plugged and circulating the oil quick enough
The dark oil colour is coming from somewhere. You should really rule out the presence of any foreign material in the screen before moving forward. That’s the reason I asked you about how fast (and how far) the converter outlet temp drops from the red section of the gauge with the engine at about half speed rather than at Low idle. What is the engine coolant temperature doing while all this is going on.?
I agree, we will look into the suction and rule that out. The engine is running cool. It doesn’t fluctuate like the transmission. If nothing is found in the suction screen, do you think transmission cooler would be suspect? If not, where would you go next? Thanks
The transmission filter showed no sign of debris, but the oil was brownish and smelled burnt. Could the discoloration be from just the oil getting hot and not necessarily from clutches slipping?
When you say "filter" are you referring to the suction screen.? (I recall that you said earlier the filter element had been inspected) I don't think so, but how many hours has the current oil been in there.? Excessive heat over time might possibly cause discolouration. I would still suggest what I posted above regarding running the engine at half speed (say 1500 RPM) and see how fast the converter outlet temp drops. If the needle on the guage falls like a stone the cooler is not the likely suspect. Do you have an infra-red thermometer.? If so some temp readings of the converter outlet temp, transmission cooler inlet/outlet temp (both oil & coolant) and radiator inlet/oultet temps may be useful numbers to have. See the attached pressure test procedure. I would suggest that you simply measure pressures and report, don't try to adjust anything at this stage. The inlet/outlet pressures of the torque converter will be especially interesting. Has anything on the transmission (clutch control solenoids, ECM, etc, etc) been replaced relatively recently.? Do you have any idea when the transmission clutch pressures and clutch fill times were last calibrated.? How many hours are on the machine and when was the transmission last overhauled.?
I had my mechanic start troubleshooting. He checked pressures and all were good except for the lube circuit. It had no pressure. Pulled the suction strainer and found remnants of part of the old speed sensor that was damaged from before I bought it. We have replaced that sensor. Found the treads and copper windings. Photo below. He cleaned and rechecked pressures and only got 5psi on the lube circuit. Something is not allowing pressure to build (washed out orfices, bypass valve stuck open). That’s where are at so far.
Attached the powertrain pressure specifications. According to what I see that machine was originally built with a torque converter equipped with a freewheel stator and a lockup clutch for load & carry operations. If that converter has not been rebuilt back to a "normal" version using a fixed stator it might pay you to test converter pressures & operation. A slipping lockup clutch could also cause the oil to become hot and discoloured. Check the converter Serial Number and Arrangement Number on the tag on the housing. Another thought. Does the machine have any electronic faults.? Is the SERV CODE icon on the dash panel lit all the time.?
If you get into changing the main filters on that unit make sure to pressurize the hydraulic tank with 1 psi for start up. I took care of 3 of same unit and seen one take out the pump on start up by someone else. There is a pressure test station just behind the cab on the left side that that has one which is pilot pressure test port. I always hook up a hose onto that one, Hose has tiniest hole in it going into a pail for start up to bleed that pump so the main pumps can kick in just to get the boom going up and pumps bled. One of the 3 loaders lost the pump at 8000hours, and they are all tied piggy back one onto the other and about 3 plus feet long and very heavy. If you ever loose one it is a cab off job just to let you beware of loosing one because it was air locked. I made a stub filter for the outside filter in the compartment with the two of them right beside the hydraulic tank to make the inner one way easier to do. Simon C
I had a very similar headache on one of my loaders a while back. It turned out to be the torque converter cooler. It looked fine from the outside, but it was partially plugged up inside with fine gunk that a filter wouldn't catch. The oil couldn't flow through it fast enough to cool down once the machine was under load. An easy way to check might be to get an infrared temp gun and shoot the inlet and outlet lines on the cooler while it's hot. You should see a pretty significant temp drop across it. If they're nearly the same temperature, I think you've found your problem. If the cooler checks out, the next thing I'd probably look at is the converter outlet relief valve. I've seen them stick and cause the exact symptoms you're describing. Good luck.
Interesting. I will look into it. I didn’t know there were different types of converters. We do use it for load and carry to feed the plant. It’s been great and a big fuel savings over the 988 we used before. No service codes
How many total hours does the machine have on it and do you know if the converter has ever been rebuilt previously.?
I don’t have that service history. It came out of a big quarry on Nevada. It’s got about 26,000hrs so it’s on a second or third life.
With 26k hours it should have been rebuilt at least once. The $64k question is how long ago was that.? Also the freewheel stator clutch was an Achilles’ Heel on that type of converter. Have a close look at the converter for Serial Numbers, etc. If it came out of Nevada you might just find a Cashman or Western States rebuild plate on it.
Iron King also does rebuilds & used parts for these, they buy a lot of ex mine equipment, they are in Oregon & Nevada. They also do a lot of YouTube vid’s