This machine has a problem of transmission overheating, the level is OK and no air within the transmission oil. I checked the engine coolant temp and fan motor found it OK, the overheating only with the transmission and torque oil. Oil cooler is OK. I checked the screens of scavenge for torque and transmission and found no obstruction. The only wrong thing is the torque converter inlet pressure is 160psi and specs is 130psi. I changed the torque inlet relief and the same pressure is present. Please advise is that high pressure make overheating? Or anybody has another advice to do. @Nige
What is the coolant temperature into & out of the radiator.? You state that "the cooler is OK". How did you check the cooler to come to that conclusion.? What is the oil temperature into & out of the cooler when the powertrain oil is overheating.? What is the coolant temperature into & out of the cooler under the same conditions as above.?
Converter inlet pressure is only really relevant at first startup when the oil is cold. More important, what is the converter outlet pressure with the powertrain oil at normal operating temperature, the engine at full throttle, and the transmission stalled in 3rd speed against the brakes.?
* The cooler shell tubes all is clear no one is plugged and no oil leak. * I didn't measure temp difference across the radiator because the coolant temp doesn't exceed 83°c. * truly I didn't measure the temp difference across power train cooler when overheating, I depended on cooler inspection to know its condition.
The outlet pressure is as specs 55psi at the mentioned conditions.
And right there is a clue…….. The coolant temp should be going way above 83 when the powertrain oil is overheating if the powertrain cooler and the radiator are working correctly. Start by shooting all the temperatures I mentioned a couple of posts above. Radiator in/out and oil cooler in/out for both coolant and oil. Post back with your results.
Look bro, yesterday I increased the max. Pressure of fan pump to 2800 "when I checked it was 2100pai" and then test the machine for 2 hours, no overheat happened. I parked the machine and when I inspected the oil levels today, I found no oil in transmission sump. When I drained the TC sump to check the scavenge screen, the TC drained more than 40Liters. Something prevent oil to exit from TC. I checked the scavenge screen and scavenge pump and found they well. I checked powertrain inlet and exit ports plus lines found all good. May be something inside the TC make this problem?
I checked the powertrain oilcooler inlet and exit ports plus lines.
Gotta be the first time in forum history @Nige has been referred to as “bro” let alone addressed by “look bro” Going to be hard to beat this on a Saturday.
Bro Nige could be a new screen name
What's the problem? I'm sorry if it's not appropriate to say this. I learned a lot from him.
I never said there was a problem with it, just that it’s a first. I just find it funny, that’s all.
Sounds like high internal leakage in the torque which would cause heating. Torque would need to come out and be rebuilt.
This internal leak will result in charging all powertrain oil to the TC and emptying trn sump? Advise please.
Can you confirm the serial number? JJ8 is coming up as a D8, if you’ve got leakage in the torque, you can do a stall test and shut machine down and measure the amount of oil that comes out of the torque against spec. I would also check the scavenge section of the pump and make sure it is performing like it’s supposed to, run the hose into a bucket and make sure it pulls the oil out quickly. To clarify, leakage inside the torque can produce more oil than the scavenge section can keep up with, a weak scavenge section can also leave too much oil in the torque.
Sorry it's D8 not 10, I wrote it by mistake. I checked the scavenge and it provides oil but truly I don't know how healthy is it. It has two inlet ports from TC and trn sump and I have no specs for the flow exiting how much should it be.
Draining 10 gallons out of the torque is a lot, can you put the torque scavenge line in a 5 gallon bucket of powertrain oil and see if the pump picks it up? It’s possible there’s a blockage in the hose or something of that nature.
I thought about that if any hose is plugged or two hoses exchanged in place of each other but found nothing. May be I'll change the powertrain pump by another and see the result.
I would do the bucket test before you swap pumps. Could quickly rule out the pump and move in the direction of the torque. How many hours on this machine?
You are right. I'll do this first. The machine has only 120 hrs.
Yea I definitely wouldn’t go throwing a transmission pump at it with only 120 hrs. Dealer support?
Or Bro Nigeria.
Not sure what Captain Manering or Awkright will think of being called Bro . Don’t tell ‘em yer name Pike! Bit of English humour lads. I’m sure the Nige will understand the bits that get lost in translation with our African friends Makes me smile though.
Why all these comments on my reply? I think it is enough. If you have no useful info please don't add reply.
No disrespect was intended for anyone. There's a lot of knowledge on this forum.
No offence intended whatsoever. Just abit of fun. By the way,can you clarify your D8 series please?
It's a new "no letter" D8. As far as the power train in concerned, similar to a D8T.
Oh right. Thanks. I was wondering if it was J8B series T
The scavenge is working efficiently. I don't know if the problem with the manufactury material.
And yet in an earlier post you stated that you drained 40 litres of oil from the converter housing. On the face of it that indicates the converter housing is not being scavenged correctly. As per the earlier question from @ahart - what is the dealer saying/doing about the problem.?
The dealer has no more solutions. They communicated with CAT and waiting.
I believe that this should be a dealer problem not a @Sameh problem to fix. I am not familiar with this model dozer and don't claim to know anywhere near as much as the other guys help you on this, but this seems very odd to me... how did you come to the fact of overheating... dash temp gauge, service codes? Does it have trans temp gauge, if so what is it reading? Has that been verified with an IR temp gun on a pipe near the temp sender? You said earlier that the engine coolant temp is only 83*C.... others have already pointed out that coolant should be a lot hotter if the transmission is overheating. So my thinking is are you sure it is actually overheating and not a bad sender giving a false reading? This may have already been ruled out and I have missed it in reading though but wanted to ask just in case.
Look, First the operator claim was about high trn temp. And by tracing the problem we found that all trn oil drawn and sent to torque and not exit back to trn. So the high temp is result and the engine coolant rises temp in final. We checked hoses, Pipes, TC oil cooler for any plug but found nothing.
So if you have checked it... what was the transmission temp getting to max? What was engine temp getting to max? Also Nige has a very valid point. @Sameh you will have to explain this a bit more please?
I would nearly bet my balls the problem is in the torque converter.
It would seem so but I couldn't find the temps anywhere and that should have been double checked early on I was thinking. On the torque converter, I think the OP means that the housing is indeed flooded with 40 Lts and that the pump has been checked and it is up to spec, but cant keep up with the leakage.... not sure though?? As a nail in the coffin for the Torque converter leakage, the trans lube pressure should be checked if not already and one would expect it to be very low. The port should be after the cooler in the circuit somewhere, flow creates the pressure for it and so low pressure means low flow... that is how the older non electronic machines that i have had experience with work anyway, someone would have to confirm if I am correct on this in relation to this machine. I could be completely incorrect and don't mind being corrected at all.
Look dear, the problem first was a complaint of high trn temp occur after 3 or 4 hour work. When I checked the oil levels all oil levels was correct except trn oil was low, I adjusted it and measure inlet pressure of TC when the oil is cold, it was 30 psi higher than specs. I tested the machine for 2 hours, it was good. But when I came the day after and checking the trn oil level, I found no oil. I drained the TC oil to see the screen and found too much oil exiting from TC, more than 40litres. So all these days I was wondering why oil doesn't exit from TC. I checked lines if it fitted in the wrong place or plugged but all correct and clear. I checked the Powertrain oil cooler and found it OK. I checked the TC outlet relief pressure, it was as specs 55psi. The question I want to know is TC has internal passages between the oil path which rotate the turbine and the TC sump? or what make oil not to drop to sump and complete path to the outlet relief then cooler then trn path? The oil on TC sump collected in which condition? @nigvPlease advise.
You may not be aware of this but the outlet relief valve for the converter controls the MINIMUM pressure of the oil leaving the converter, not the maximum. I wouldn't worry too mcuh about the inlet pressure at cold startup being up a bit above specification. It may be an indication of something but I would say "not proven" at this point. What type & grade of oil is in the powertrain system.? Oil entering the torque converter has two paths. First is the oil passing through the converter assembly and out via the outlet relief valve to the powertrain cooler. This oil flow is what takes away the tremendous amount of heat generator by torque converter operation. The outlet relief valve maintains the minimum pressure inside the torque converter assembly. Second is internal leakage within the converter components - quite a lot of it in fact. All the oil that leaks internally from the converter finds its way into the bottom of the housing and is sucked away by the scavenge pump. If a converter has excessive internal leakage the quantity of oil in the converter housing can exceed the capacity of the scavenge pump. Eventually this could cause the oil level in the transmission/rear case to fall because the oil is accumulating in the converter housing and not being returned. If this situation continues it could starve the suction side of the powertrain oil pump transmission charging section and result in cavitation.
TDTO 50 Many thanks, Nige for your great priceless data. Another question to be fully understand. According to your words if the torque outlet pressure is low, it will lead to cavitation as it controls the pressure inside torque and the inlet pressure affects only in cold start up. Am I right?
That could be a reason for the high inlet pressure when cold. If you have TDTO 30 available change the oil and try a test with that oil. I was once a big believer in 50 oil in transmissions in hot climates but after a lot of testing I have changed my opinion and would now only recommend to go with 50 in cases of extremely high ambient temperatures - probably over 50 DegC. No, that is not what I was saying. In the case where a large quantity of oil accumulates in the converter housing for whatever reason the result is that the oil level measured on the transmission dipstick goes down. You found this yourself. If the oil level in the transmission case goes down far enough it can potentially create cavitation in the suction side of the section of the transmission pump (remember that it is a 3-section pump) that supplies the transmission and its controls.
Many thanks, Nige Often I'll change the TC and see the problem disappear or not.
EDUT: Sorry I misunderstood when you said "I'll change the TC" that you were referring to the oil. That would be a good first step. Personally on a machine with only 120 operating hours that is still under factory warranty I would be very careful what I did to the tractor unless I had a person from the dealer calling the shots alongside me.