Cummins QSC “Gear Temperature Alarm”

[brewster16]

Again - if your gear cooler was plugging up on the raw water side, your engine temperatures would also increase. All of the engine's cooling water goes through the gear cooler.

I've always thought the engine cooling occurs in the larger heat exchanger bundle and the transmission gear cooler was it's own separate raw water flow through it's tube? (Such that the gear cooler can be clogged causing increased gear oil temp) and the main engine heat exchanger takes care of the engine temp? Am I incorrect?

 

[ttmott]

I've always thought the engine cooling occurs in the larger heat exchanger bundle and the transmission gear cooler was it's own separate raw water flow through it's tube? (Such that the gear cooler can be clogged causing increased gear oil temp) and the main engine heat exchanger takes care of the engine temp? Am I incorrect?

Yep, incorrect. The coolers are in series - one after the other. If any one of them (fuel cooler, engine cooler, aftercooler, or gear cooler) gets restricted then all will suffer adverse effects.
As an edit - go take a look at your engine and follow the raw water hoses and tubes; you will see in short order.

 

[Woody]

My transmission is ZF280IV. Both transmission fluids levels are at the top full mark. Still no grinding, popping, sticking or any other abnormal noise from the port transmission during shifting or running. However, once again port gear temp inches up 40F higher then starboard side. Are these findings all pointing to clogged transmission gear cooler?

How are you reading the dipstick? According to ZF it should be checked when warmed up within 2 minutes after it's shutdown. It should be pushed all the way in then pulled out to read oil level, some units are different that's why I mention it.

 

[Woody]

I've always thought the engine cooling occurs in the larger heat exchanger bundle and the transmission gear cooler was it's own separate raw water flow through it's tube? (Such that the gear cooler can be clogged causing increased gear oil temp) and the main engine heat exchanger takes care of the engine temp? Am I incorrect?

Look at the last two diagrams, start with the bottom one first, follow the light green water flow
https://www.sbmar.com/articles/cummins-mechanical-b-c-coolant-and-raw-water-flow-diagrams/

 

[brewster16]

That’s quite helpful….thanks everyone

 

[brewster16]

So, after experiencing gear temp alarm over July 4th week away, today I opened up my gear cooler to find out it was quite clogged with scale and “gunk” and a petrified shrimp. I spent a good part of the day flushing and back flushing the gear/fuel cooler with the garden hose followed by a 6 hour soak with barnacle buster. Tons of discharge blew out once I reassembled everything and started the port engine. Full cooler service this winter for me.