Cat D4H overheating the converter transmission

Hello dear

I have this dozer CAT year: 1986, model D4H, serial: 08PB00451, série II

We have recently bought this dozer, upon couple hours I noticed the overheating in the transsmision, we have decided to replace the next parts,



3T8316 planetary transmission sn 1CE514-1675 :

6T8687 DISC FRICTION (5)
6Y7965 DISC FRICTION (17)
9P6799 PISTON CLUTCH (1)
3P7019 SEAL METAL (1)
9P7101 PLATE CLUTCH (4)

valve selector and pressure control

9P3041 spring inner (1)
7G4842 spring outter (1)

Control Valve Transmision Hydraulic 8P8984:.

3D2824 Seal o-ring (1)
6Y2349 Connector Special (1)
8M1322 Spring (1)
9S8008 plug o-ring (1)
3D2824 Seal o-ring (1)

So after done the service and those parte replaced, we have placed in service and after 30 hours, again the temperature to continue overheating,

And I went to check the oil filter and this was suctioned look like this did any vacum also, I already replaced.

So now I am replacing the pump as well..

Did you run any pressures convertor in and out did you check the cooler sounds like you replaced a lot of parts without knowing what was going on in there

Dave Hello,
We have stripped down the transmission after be replaced the wheel impeller, and wheel turbine, and there are some pieces were replaced because looked like damaged,

So now we have the same problem with the temperature after 4 hours working,

The pump was replaced and now the strong or power was lose the

See the oil filter picture was suctioned, so we have replaced the pump and one filter but the strong/power gone down....

I have to agree with Dave Neubert about checking pressures before just pulling the transmission out for overhaul.

The older gentleman I started working with years ago always pulled the coolers and replaced them when installing a rebuilt transmission. I've done them and not replaced the coolers but always flushed and pressure tested them at a minimum. Anything that looked like a problem and they got replaced.

With that amount of trash in the strainer I would replace the cooler did you clean out the frame where the trans goes that is a lot of junk or is this the first time you cleaned the strainer

check the main P1 P2 convertor in and out and let us know what you have

Crisanta said:

See the oil filter picture was suctioned, so we have replaced the pump and one filter but the strong/power gone down....

Click to expand...

Is that a genuine Cat filter.?
Did you cut it open to look for particles inside it.?

I agree with other posters above. You are replacing parts before doing a full diagnosis (e.g. p1, P2, converter pressures, etc.)
The diagnosis should be pointing you in the correct direction but you do not appear to have done any yet. You will continue to replace parts until finally you will replace something that fixes the problem. That is very expensive for you and not how the process works.

Here is the pressure chart for the D4H II powertrain.

Hello Dave, and Nigel thanks by your response.

The strainer was new installed CTP brands, when the parts were installed, but the cooler was not flushed or replaced.


Please see the picture a lot trash in the strainer...


Well I will go to replace the oil, strainer and flush the cooler, and run the pressure test.

If you would like a copy of the procedure for testing the pressures just ask.

Yes, Nige I would appreciate the copy procedure to run the Pressure test,

Thanks a lot will be highly appreciated..
I not sure if you can send it from here or from your email here the mine danyr42@gmail.com

Now we are pulling down the cooler will be flushed and the tube as well..before to install the new strainer.

No problem. Attached is a file in Adobe pdf format. If you have access to a PC or laptop it will download fine for you.

Also in the Test & Adjust are the details of adjusting the transmission control linkages. It would be a good idea for you to inspect them for wear and to check the adjustment, just to be sure.

Thanks a lot Nige, I will go to check the procedure...

Dear Nigel and Dave see the cooler's picture, I will go run some pressure test and flushed.

The outside looks pretty grim.
I wonder what the inside is like.?

Its what is on the inside that you cant see that may be a problem did you check inlet and out wit a heat gun to see if it is cooling properly

Looks like there's a fair amount of dirt or bent fins on that cooler package.

First thing I do for any overheat condition is make sure the cooler is clean, all shrounds are in place and that the fan is in good condition. Its the cheapest/easiest place to start.

Hello Guys.

I am back again, I have more time to make more test, the cooler was cleaned and flushed and installed again.

So I was doing the test in the A port Valve priority, so the pressure with the oil cold, were low Idle 390psi High idle 442psi.

But after 45 minutes working the pressure were down Like 160psi and Hi 330psi.


Any advice from you..?

Thanks..!!

First question. What type of oil are you using in the transmission and what viscosity is it.?