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Regular Contributor

Re: Caterpillar D5H Torque Convertor oil overheating

Any excessive leakage in the transmission and torque converter results in reduced oil flow through the cooler and therefore reduced heat transfer. If your machine condition is the same as machine in previous posts ( torque convertor known to be good and transmission pressure tests correct) and engine is not overheating as well then check the following:

1. Torque convertor inlet relief valve (ratio valve) dumping oil back to sump which reduces flow to torque convertor and cooler.

This valve is located in the transmission hydraulic control valves.

2. Seals on the sleeve tubes between hydraulic control valve and transmission housing

3. Internal tube in main case and frame that takes oil coming from transmission to the torque convertor

New member

Re: Caterpillar D5H Torque Convertor oil overheating

I am having a similar issue. What did you finally determine to be the root cause of the overheating problem?
Contributor

Re: Caterpillar D5H Torque Convertor oil overheating

Hello, does anyone else have any ideas that might be causing the problem?
Thanks
Mike
Contributor

Re: Caterpillar D5H Torque Convertor oil overheating

Cody I found this on another post on this forum I didn't know if u had saw this or if this info would even pertain to my problem. I just wanted to refer it to u.

Jevlar Contributor
6/22/12
A common failure on these transmissions is a spool and slug in the valve body that causes low flow through the converter and thus low flow to the cooler.
Updated parts are avaliable.
 
A pipe inside the transmission case can also crack causing the same problem and is replaced by a hose.
check trnaspump pressure, converter in and out pressure.
Contributor

Re: Caterpillar D5H Torque Convertor oil overheating

Cody just wanted u to know that this Dozer did this the very first day I bought and used the Dozer.

Thanks
Mike
Contributor

Re: Caterpillar D5H Torque Convertor oil overheating

Hello Cody, thank I for replying. I really appreciate it. When I operate the Dozer I only push in 1st gear at a good rpm and it still overheats. If I back up or stop and let the machine just set and run the oil gauge doesn't cool down. If I let the machine set and idle at a really really low rpm, the oil gauge will drop to around 210 degrees F and just stay there but as soon as I start moving and just driving a very short distance without pushing any dirt, the gauge will jump right back up to 230-250 degrees F.
Thanks
Michael
Administrator
Employee

Re: Caterpillar D5H Torque Convertor oil overheating

Hi Michael,

We also found this information from the OMM (Operation and Maintenance Manual) It suggests that
the oil level may be too high.

1. Note: When you are operating the machine on severe slopes, the
quantity of oil in the transmission can be increased up to 10
percent. When you are operating with the increased oil quantity,
prolonged operation in some machines can cause high transmission oil
temperatures. After the work on the severe slopes has been completed,
drain the excessive oil quantity from the transmission.
 

 

Regards,
Cody
Administrator
Employee

Re: Caterpillar D5H Torque Convertor oil overheating

Hi Michael,
I work in Caterpillar's Customer Interaction Center and have spoken with some of our experts about your issue. They believe there may still be something in your powertrain system that is not operating correctly, or the operating technique could be improved. There are several possible causes, but here are some suggestions.

 

a. the gauge may not be displaying an accurate temperature
b. the oil flow to the cooler may be restricted by something such as a partially plugged or crimped oil line either before or after the cooler
c. the cooler itself may have internal flow restrictions caused by debris or some other cause
d. high powertrain oil temperatures can also be caused by operating in too high of a gear (trying to doze too large of a load in second instead of shifting to first gear, for example)
e. cooling is also reduced when engine RPM is decreased, such as when the decelerator is used or the engine is not run at high idle.

 

If this does not help your local Caterpillar dealer can work with you to help determine the cause.

Regards,
Cody
Contributor

Caterpillar D5H Torque Convertor oil overheating

Hello, I have a 1987 Caterpillar D5H Dozer that after 1 hour of use the TC oil overheats. I had the TC rebuilt a few months back but the TC gauge still shows that it is overheating after 1 hour of use. I did not change the transmission oil cooler. Other than the overheating the Dozer operates just fine. It never loses power or slips even when the TC guage starts getting hot. I have checked all the pressures on the P1, P2 and TC test ports and the pressures are within specs according to the service manual. Does anyone have any ideas what else could be causing the overheating issue. I would like to get the machine fixed so I can use it.

Any help would be appreciated.

Thanks
Michael