servotransmision overheat in a xcat 980g 2

[mrjoe72]

hello its a cat 980g 2 serial axg 00478 is a persistent overheat in the servo oil ...we r using a 15w-40 oil ..its in a coal mine piling a stock of coal works 20 hours a day ..with a temperture of 40 centigrades ...its in a desert ...we r trying everything ..please help ...

 

[Nige]

How long has the machine been at your location..? Has it had this problem since it first arrived or has the problem developed over a period of time during operation at your location ..?

What's overheating ..? The transmission or the engine cooling system, or both..?

The transmission should not run on SAE 15W/40 engine oil under any circumstances. You should be using either an SAE 30 or SAE 50 oil that meets TO-4 specifications.

What type of bucket does it have installed..? Straight edge, V-edge, or purpose designed coal bucket ..? If it's a coal bucket what is the part number & capacity ..?

What coolant are you using in the engine cooling system ..?

Have you done a torque converter stall test ..?

Have you checked the speed of the radiator fan ..?

 

[Magnum]

I had the same interresting experience last summer when running a 980GII in Sweden and it was only around 30 degrees C.... It was in a quarry carrying crushed gravel uphill for 150m on second or third gear and at the top of the hill the transmission was boiling more or less. The transmission cooled down a bit when going back down again but then the front axle was boiling instead since the irritating "downshiftassoonasyoutouchthebrakepedal" was disconnected. The coolant temp was a little bit higher than normal but not close to overheating like the transmission and axles were...

 

[Nige]

Good point. I never asked if it was running up or downhill with material, or working on level ground. On a coal stockpile one would assume it's on more or less level ground.

On axle oil overheating on your 980G I can only assume the operator was riding the brake pedal (which one do they normally use for tramming, left or right?) on the way down the hill instead of shifting to a lower gear and letting the engine hold the machine back. I've seen a lot of issues on 992G/854G brakes for that reason, it gets even worse if the operator shift to neutral on the way down.

The torque converter in the 980G does not have a lockup clutch, therefore you would expect the power train oil to heat up noticeably if you use one for a load & carry operation.

Joe, What Part Number of Torque Converter do you have installed in the machine ..?

 

[mrjoe72]

How long has the machine been at your location..? Has it had this problem since it first arrived or has the problem developed over a period of time during operation at your location ..?

What's overheating ..? The transmission or the engine cooling system, or both..?

The transmission should not run on SAE 15W/40 engine oil under any circumstances. You should be using either an SAE 30 or SAE 50 oil that meets TO-4 specifications.

What type of bucket does it have installed..? Straight edge, V-edge, or purpose designed coal bucket ..? If it's a coal bucket what is the part number & capacity ..?

What coolant are you using in the engine cooling system ..?

Have you done a torque converter stall test ..?

Have you checked the speed of the radiator fan ..?

first its happen since coming from france to the site of work
second its the transmision only overheating
third it has a general porpuse bucket
we r using long life coolant from texaco

 

[mrjoe72]

i dont have here right now but i let you know

 

[Nige]

my servo its overheating ...its for this type of oil ???

Can we stay on one thread please, it's all for the same machine and the same problem .........!!!

Engine oil does not have the additive package required to work with transmission clutches. If you have an Operation & Maintenance Manual for the machine at your operation you will note that ONLY oils meeting TO-4 specification should be used in the powershift transmission. engine oil does not meet that specification. Using the correct oil will also prolong the life of your transmission, a failure will cost you a lot of money and downtime as well. Of course as the owner you are perfectly entitled to use any oil that you want to, but if you do use an oil that is not recommended then please don't complain that your machine has problems.

You're asking for help with a problem. We first need to rule out everything that MIGHT be causing your problem in order to get to the root cause of the problem, and using engine oil in the transmission as you are right now is is one of those issues that needs correcting. First get the correct oil in it and we can eliminate the oil as a potential source of the problem.

You have answered a lot of my initial questions, and the key thing is that the loader has had this problem since it arrived at your operation. But I still need answers to the following: -

1. Have you done a torque converter stall test..? What RPM does the engine hold at TC stall in 4th speed forward..? That will give an idea of your torque converter efficiency.

2. I would like the engine fan speed checked, just to rule out if there may be a heat exchange issue within the transmission oil cooler. If you have nothing on your site to check fan speed then at least check the temperature at the coolant inlet hose of the radiator (when the machine is "overheating" the transmission) and then do the same at the radiator outlet hose. How many degrees difference do you have ..? If the radiator is not functioning correctly for whatever reason (it could be dirty - have you checked it and maybe cleaned it just to be sure?) then the coolant returning to the transmission oil cooler will be hotter than it should be. That means it cannot lower the temperature of the transmission oil as much as it should. So as a result the transmission oil slowly overheats during operation until it generates the alarm. In that case the problem would not be in the transmnission but in the engine cooling system performance, the transmission oil temperature alarm would be the symptom not the root cause.

3. The reason I asked about the torque converter Part Number is that there are 2 Part Numbers of converter for this machine. One has a free-wheel stator and is recommended for load & carry operations, the other has a fixed stator. What type of operation are you doing, loading trucks, loading a conveyor system, moving material from once place to another (load & carry), etc ..? If you are doing load & carry how many metres are you moving the material and is the ground flat of inclined..? Knowing what type of operation you have will help to find a solution for your issue.

 

[mrjoe72]

Can we stay on one thread please, it's all for the same machine and the same problem .........!!!

Engine oil does not have the additive package required to work with transmission clutches. If you have an Operation & Maintenance Manual for the machine at your operation you will note that ONLY oils meeting TO-4 specification should be used in the powershift transmission. engine oil does not meet that specification. Using the correct oil will also prolong the life of your transmission, a failure will cost you a lot of money and downtime as well. Of course as the owner you are perfectly entitled to use any oil that you want to, but if you do use an oil that is not recommended then please don't complain that your machine has problems.

You're asking for help with a problem. We first need to rule out everything that MIGHT be causing your problem in order to get to the root cause of the problem, and using engine oil in the transmission as you are right now is is one of those issues that needs correcting. First get the correct oil in it and we can eliminate the oil as a potential source of the problem.

You have answered a lot of my initial questions, and the key thing is that the loader has had this problem since it arrived at your operation. But I still need answers to the following: -

1. Have you done a torque converter stall test..? What RPM does the engine hold at TC stall in 4th speed forward..? That will give an idea of your torque converter efficiency.

2. I would like the engine fan speed checked, just to rule out if there may be a heat exchange issue within the transmission oil cooler. If you have nothing on your site to check fan speed then at least check the temperature at the coolant inlet hose of the radiator (when the machine is "overheating" the transmission) and then do the same at the radiator outlet hose. How many degrees difference do you have ..? If the radiator is not functioning correctly for whatever reason (it could be dirty - have you checked it and maybe cleaned it just to be sure?) then the coolant returning to the transmission oil cooler will be hotter than it should be. That means it cannot lower the temperature of the transmission oil as much as it should. So as a result the transmission oil slowly overheats during operation until it generates the alarm. In that case the problem would not be in the transmnission but in the engine cooling system performance, the transmission oil temperature alarm would be the symptom not the root cause.

3. The reason I asked about the torque converter Part Number is that there are 2 Part Numbers of converter for this machine. One has a free-wheel stator and is recommended for load & carry operations, the other has a fixed stator. What type of operation are you doing, loading trucks, loading a conveyor system, moving material from once place to another (load & carry), etc ..? If you are doing load & carry how many metres are you moving the material and is the ground flat of inclined..? Knowing what type of operation you have will help to find a solution for your issue.

1 i will perform a stall test and i let you know the results
2 i will check the radiator ..but one question ...the oil of the trasmision its cooled by the coolant of the engine ?? the transmision oil doesnt cool in the oil cooler behind the radiator ?? ...or its the torque converter oil that cools in that oil coooler ...
3 i wiil check the arrengment number and find the torque converter part .or is any particular place to look at ??
4 the operation its as follows

pile the coal
load a truck
flat surface and pile distance from the trucks about 40 feet ...

and the bucket its for general pourpose ...i would like to have a v shape ..what do you think ??

 

[mrjoe72]

i would change the oil inmideatly ...for a sae 50 to-4 .... thanks in advance ...

 

[mrjoe72]

and im sorry about the other post ..im learning ...

 

[CM1995]

and im sorry about the other post ..im learning ...

No problem.

 

[Nige]

and im sorry about the other post ..im learning ...

No worries. We all had to start learning somewhere. The diagnostic process is sometimes complex and you have to think of all sorts of things that may not immediately be apparent as possible root causes. As an example of my comment above that the problem could be in the poor performance of the engine cooling system & radiator, but the symptoms (of high temperature) appear in the transmission oil. A lot of the time it's not as simple as you think.

Your machine has 2 coolers. The air-to-air cooler for the implement hydraulic oil is mounted behind the radiator and is cooled using the same fan that cools the radiator. The water-to-oil cooler mounted on the RH side of the engine is for the Power Train circuit and cools the oil for both the torque converter and the transmission. Because the same oil is used for both the torque converter and also the transmission we have to look at converter performance even if only in order to eliminate it as a possible source of the excessive heat being produced in the Power Train Oil system.

 

[Nige]

Here is the Implement Hydraulic cooler, mounted on the back of the radiator .......... make sure that you pressure wash both the radiator and this oil cooler so that cooling system performance is the best it can possibly be in 40 degree Celsius ambient temperatures.

 

[Nige]

Here's another piece of information. If it still has the original converter installed then somewhere on the torque converter there should be a plate with the Arrangment Number 8E-4735 and the Serial Number 3JT06786.

8E-4735 is the torque converter arrangement that does NOT have the freewheel stator. However for your type of operation loading trucks I do not see that one would be necessary.

Because coal is very low density I would have thought that a purpose-designed coal bucket would be the best. This would have a straight (not V) lip and a bolt-on cutting edge without teeth.
More questions: What size is the coal approximately ..? Has it already been crushed ..? If the answer is yes then I would say a coal bucket would enable you to move more material per cycle. What is the Part Number (plate should be on back side of bucket, RH side) of the bucket you have installed right now ..? If it has no Part Number do you know what cubic capacity it is ..?

I cannot see a specific coal bucket listed for the 980G Series II. The biggest GP bucket capacity is 6.1 cu.m (8 cu.yd) and would have replaceable bolt-on edges like the illustration below. I think that would be big enough for you.

 

[mrjoe72]

Here's another piece of information. If it still has the original converter installed then somewhere on the torque converter there should be a plate with the Arrangment Number 8E-4735 and the Serial Number 3JT06786.

8E-4735 is the torque converter arrangement that does NOT have the freewheel stator. However for your type of operation loading trucks I do not see that one would be necessary.

Because coal is very low density I would have thought that a purpose-designed coal bucket would be the best. This would have a straight (not V) lip and a bolt-on cutting edge without teeth.
More questions: What size is the coal approximately ..? Has it already been crushed ..? If the answer is yes then I would say a coal bucket would enable you to move more material per cycle. What is the Part Number (plate should be on back side of bucket, RH side) of the bucket you have installed right now ..? If it has no Part Number do you know what cubic capacity it is ..?

I cannot see a specific coal bucket listed for the 980G Series II. The biggest GP bucket capacity is 6.1 cu.m (8 cu.yd) and would have replaceable bolt-on edges like the illustration below. I think that would be big enough for you.

View attachment 86064

ok thanks a lot ..this is the bucket that i have in the loader ...the coal its allready crush ..with an size of aprox 3 inch ...im going to check that oil cooler ..the one its locates at the side of the engine ...im changing the oil for a sae 50 to-4 ...i check the converter ratio valve ..

 

[Nige]

Changing the oil will improve things, I am sure of that. But in your type of climate and working with coal you also need to ensure that the radiator is perfectly clean and that any oil leaks are repaired fast so that the machine cannot accumulate coal dust around the location where the oil is leaking. I would estimate the radiator should need washing at least once a week, perhaps twice, to keep it in perfect working order.

 

[mrjoe72]

Changing the oil will improve things, I am sure of that. But in your type of climate and working with coal you also need to ensure that the radiator is perfectly clean and that any oil leaks are repaired fast so that the machine cannot accumulate coal dust around the location where the oil is leaking. I would estimate the radiator should need washing at least once a week, perhaps twice, to keep it in perfect working order.

ok i wash the radiator everyweek but im going to check if the radiator of the transmision if has any difference in the size ..maybe the oil cooler is not enough for this temperature ..

 

[Nige]

You will be surprised how the efficiency of the engine radiator affects the efficiency of the engine oil cooler. As I said before you have to remember that symptoms appearing in one place can be from a root cause in somewhere totally different.

Unfortunately there is no high ambient temperature cooling package available for this model of machine, but even if there were it would most likely be a higher capacity engine radiator, not a higher capacity transmission oil cooler.

Quite frankly the more I think about it the more I am convinced that the root cause of your problem most probably lies in the engine radiator not the transmission oil cooler.

 

[mrjoe72]

You will be surprised how the efficiency of the engine radiator affects the efficiency of the engine oil cooler. As I said before you have to remember that symptoms appearing in one place can be from a root cause in somewhere totally different.

Unfortunately there is no high ambient temperature cooling package available for this model of machine, but even if there were it would most likely be a higher capacity engine radiator, not a higher capacity transmission oil cooler.

Quite frankly the more I think about it the more I am convinced that the root cause of your problem most probably lies in the engine radiator not the transmission oil cooler.

ok im thinking in the possibilities of make a more capacity radiator ..

 

[Nige]

ok im thinking in the possibilities of make a more capacity radiator ..

That may well be a possible solution. Mesabi make replacement radiators if you have a Mesabi agency in Colombia. They could probably design something to fit in the existing space and use the existing connections. However it would not be cheap.

To ensure that your radiator is working at the highest possible efficiency you need to use a top-quality EXtended-Life (ELC) coolant, not glycol-based coolant. You said you were using a Texaco coolant, exactly what is is called ..? The only Texaco product that I can find that meets ELC requirements is HAVOLINE EXTENDED LIFE PREDILUTED 50/50
ANTI-FREEZE/COOLANT. If you are not using this product then you are losing cooling system efficiency.

Last thing you need to check is that your radiator fan is rotating at the correct RPM. A "slow" fan will also drastically reduce radiator efficiency.