D7F Transmission over heating after 3-4 hours

Here are some scans. The speed and directional taps will be under a plate on top of the transmission. Probably 1/8NPT thread, and some others could be 9/16 UNO. Do not automatically think every pressure tap is going to use the same thread. The last lot of photo's show the location of the pressure taps and testing. Also shows the setting of the transmission controls. Also have included the troubleshooting guide from the manual. You could have air getting into the system when the oil is hot and hoses and seal soften causing low oil pressure.

I also scanned in parts manual pages in case you want to get the expensive silicone O-Rings and reseal the transmission control valve.Someone may be able to decipher what you need for that. My D6D had an issue where it would sometimes when the oil was hot would not engage properly, the transmission would slip and the dozer would barely move. I replaced the springs in the transmission control valve (had to come from singapore so took a couple of weeks) and the O-Rings and adjusted the control spool valves so far it seems good, but I have not given it a decent run yet.

Hello RC, thanks a lot for your help here, this will keep us progressing until the Manuel arrives.

Hello Nige, We finally got back out there to test some pressures, see below.

At cold Idle
Pump direct 500PSI
Pump Filter 400PSI
Torque Out 57PSI

Warm
Pump Direct 400PSI
Pump Filter 375PSI
Torque Out 37 PSI
Steering pump port 375PSI
Converter Inlet 85PSI high idle
Converter Inlet while in motion and high RPM 60 PSI

The converter inlet pressure is meant to be minimum 140 PSI. Considering the Touque converter is new and the tractor had the problem before the torque convertor was replaced, we have removed the pressure control valve to clean it and check internally for damage. There was a bit of hard black Debree in the valve, the rest looks ok. we are guessing that we need to add or remove the tensioning washers under the springs to adjust the pressure. We are still waiting for our manual to arrive so are just going off the information provided.

Are we on the right track?

You seem to be missing the pressures for the speed and directional clutches.
What about pressures when it is playing up?

Wiggo said:

The converter inlet pressure is meant to be minimum 140 PSI.

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Not so. T&A is not clear on this. 140psi converter inlet is MAX pressure with cold oil. You'd usually expect something around 100-110psi.

.RC. said:

You seem to be missing the pressures for the speed and directional clutches.
What about pressures when it is playing up?

Click to expand...

Need the answers to those questions.

Wiggo said:

Torque Out 37 PSI

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Is that with the transmission stalled against the brakes in 3rd speed forward.?

Still need an answer to the question of what type/grade of oil you are using in the transmission.