Procedure to test Trans cooler

Dozer is a 1996 D8R serial number 7XM00754

Does anyone know how to make sure the cooler is working correctly?

Experiencing elevated trans temp and trans oil seems to have foam in it.

I'm going to pressure test the trans and torque converter and would like to test the cooler as well

Thank you for any help

Foam in the oil suggests the possibility of sucking air somewhere between the transmission case (effectively the power train oil pan) and the transmission pump inlet port. Check the condition of the suction hoses/clamps/O-Rings, or whatever seals the lines.
Are you using TO-4 specification oil..?

Test cooler efficiency by first getting the tractor up to normal operating temp range for both engine coolant and power train oil.
Stall the transmission in 3rd speed. As the power train oil temp is rising towards whatever temp sets the high temp alarm off, measure the temperature difference between the oil inlet & oil outlet ports of the transmission cooler and post the results.

Nige said:

Foam in the oil suggests the possibility of sucking air somewhere between the transmission case (effectively the power train oil pan) and the transmission pump inlet port. Check the condition of the suction hoses/clamps/O-Rings, or whatever seals the lines.
Are you using TO-4 specification oil..?

Test cooler efficiency by first getting the tractor up to normal operating temp range for both engine coolant and power train oil.
Stall the transmission in 3rd speed. As the power train oil temp is rising towards whatever temp sets the high temp alarm off, measure the temperature difference between the oil inlet & oil outlet ports of the transmission cooler and post the results.

Click to expand...

Yes I use cat oil.

I got the engine and power train up to temp and then stalled in third for about 15 seconds. This made the power train temp go up to 240ish on the gauge. When using a laser thermo, the inlet was 100 degrees and the outlet was 90 degrees. I did not have material to push, the next time I do and it heats up to where I lose power I will do this again.

To confirm, the trans cooler is the smaller radiator correct?

I also tested:
*Torque converter inlet pressure (140psi at high idle)
*Low pressure torque converter charging pump (150psi at high idle)
*Trans oil pump (510psi at low and 560psi at high idle)
*Converter outlet pressure is supposed to be 60psi but I don't have a huge small enough to register 60psi

So depending on what you say about the cooler temps it seems the dozer passed all tests except the converter outlet pressure which can't be confirmed as of now

Again the issue is after a few hours of pushing the trans temp raises and there is severe loss of power. Trans oil level is slightly high

I would suggest to address the possible suction air leak issues first by checking all the suction hose(s) and at the same time fitting new O-Rings to all of them. The cost of the O-Rings might be $10.

If the TC Out temp gauge was registering close to 240 DegF then how could your power train cooler be registering 90/100..? The oil arriving at the cooler should be at the very least in a similar range as TC out, maybe around 200 or even more. I agree with what you suggest and do the same test again when you have material to push and see what that throws up. On the face of it a 10 degree drop across the cooler would be in the ball park, but a lot also depends on the engine coolant temperature.

Another test you can do is to stall the transmission as before and run the TC Out temp up until the alarm goes off. It won't hurt the machine. When the temp alarm sounds, shift to neutral and keep the engine at High Idle. Watch how fast the TC Out temp gauge falls, within seconds it should drop like a stone to maybe 10-20 degrees above the engine coolant temperature.

Power train oil cooler is the vertical one in the illustration below.

Nige said:

Power train oil cooler is the vertical one in the illustration below.
View attachment 209484

Click to expand...

I will redo the temp test with the proper cooler.

I got the machine up to around 150 degrees but it didn't want to go higher without a load. During stall it would quickly go to 250 then once I switch to neutral and idle down it would drop to around 150 again.

I did only spend about 10-15 minutes warming it up. Maybe I need longer or need to move some dirt. I will keep in touch

Nige said:

Power train oil cooler is the vertical one in the illustration below.
View attachment 209484

Click to expand...

The vertical one above image A A and below 28 correct?

Robert0769 said:

I did only spend about 10-15 minutes warming it up. Maybe I need longer or need to move some dirt. I will keep in touch

Click to expand...

To get the system fully heat-soaked from cold will require at least 1 hour, probably as much as 2.

Robert0769 said:

The vertical one above image A A and below 28 correct?

Click to expand...

Correct.

Also, I think some hoses may need to be replaced. After I recently replaced the implementation pump I noticed yesterday a hose on top of the trans pump is wet at the connection as well as the hoses below the trans pump are a bit soaked. I did use all new o-rings.

Are you blew to confirm which hose is the inlet?

Had 2 different Cat techs come from two different counties. Both did not hook up to anything or do anything except check the filter. There is some clutch material in there. They say replace clutches.

Told that to cat technical who said warm it up, then high rev stall in second gear and look if the drive shaft stops. If it stops then it's probably not clutches. I did so and the shaft stopped. Called technical back and he seemed confused and said yeah I agree it's clutches.. so little confusion there. Guess a clutch job is needed. Asked Cat how much to rebuild trans.. they gave prove and said they won't warranty it unless they also rebuild the entire powertrain. So I'll be looking for other options. $25k on unwarrantied labor sounds crappy.

I'm going to try to find a reputable place to rebuild the clutches.

I'm going to get the maintenance book and see if it's as easy as a final drive (everything just fits together) or if I'll need torque specs or more in depth stuff. Anyone have experience with rebuilding the trans? Does it all fit together just like a final drive? No torque specs or special something

Before you go tearing a transmission apart that might not need it, answer one question.

Does the drive shaft stop spinning when you select ANY gear either forward or reverse.? You don’t have to have the engine at 100% of High Idle to do the tests. So that is 6 tests in total you have to make. Watch the shaft carefully regarding how quickly it goes from full speed to a dead stop.

First gear same result forward and reverse: low idle shaft slows but keeps spinning and doesn't stop. High rev it keeps going fast. Tracks do not move or even feel like it wants to.

Second gear same result forward and reverse high or low idle: stops immediately, tracks do not.

It appears from those tests as though first speed #5 clutch has failed, although I note you did not make the tests in 3rd speed, only first & second. The slipping clutch is most likely where the addittional heat was coming from that was causing transmission cooling issues.

Looks like transmission out time.

Those clutches are controlled by solenoid valves that can be a problem. You should pull rear trans cover and test #5 clutch pressure. You can swap modulating valve from 3rd speed to see if that helps.

Mobiltech said:

Those clutches are controlled by solenoid valves that can be a problem. You should pull rear trans cover and test #5 clutch pressure. You can swap modulating valve from 3rd speed to see if that helps.

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Hang on a sec. This is a 7XM-prefix tractor. Don't they have manually-controlled speed and direction spools in the control valve..? See below.



I'd be tempted to drain the powertrain oil and pull the suction screens. There are two of them - see attachment. If the #5 clutch has failed there ought to be a load of burned debris in the screens.

Sorry I didn’t run the serial number. Thought it was a newer 8r with modulation valves.

I must admit when you posted that I had to look just to make sure.....!!

Next step. Remove screens and inspect for burned clutch friction material.

I did the test again.

First gear forward keeps spinning
First gear reverse stops quicky
Second gear forward stops quickly
Second gear reverse stops quickly
Third gear forward stops quickly
Third gear reverse stops quickly

I will check screens when I drain and collect oil for sos samples.

In the past, the rear screen had lots of clutch material (almost like small black rubber thin branches) and metal flakes. The screen by the torque converter is missing from what I was told but I think the tech lied and never even checked. We shall see right? Speaking of.. dunno if any remember me saying the San Diego and Riverside cat dealers are messing with me and constantly try to charge more than they should. Well I got a quote for rebuilding the trans from them and not only is it expensive but they say they won't warranty it unless I allow them to rebuild my entire powertrain, torque, pumps.. I men everything. So I called two different states.. one on the east coast and one in the mountains.. I told them my issues and didn't leave anything out. Not only are they several thousand more affordable but they give a 3 year warranty (1 year 100% covered, 2 years 60% and 3 years 30%) vs no warranty here. I'll be making a road trip soon. California has some issues but they get away with it.

This time I asked the tech to do a sample and check screens but he forgot his stuff for that so I'll do it soon. This job is almost over so I'll do it in the next week or two.

Robert0769 said:

I did the test again.
First gear forward keeps spinning
First gear reverse stops quicky
Second gear forward stops quickly
Second gear reverse stops quickly
Third gear forward stops quickly
Third gear reverse stops quickly

Click to expand...

So the shaft stops spinning in every speed EXCEPT 1st forward.
I don't know what anybody else thinks but to me this is weird for either of the following reasons: -

1. If the clutch for 1st speed had failed the shaft would keep spinning in BOTH 1st speed forward and 1st speed reverse because the same clutch is used for 1st speed in both directions.

2. If the clutch for forward direction had failed the shaft would keep spinning in all forward speeds, i.e. 1st, 2nd, and 3rd.

I would still go looking at all THREE suction screens. See attachment. Post photos of whatever you find.