Disconnecting Transmission cooler on Eaton 18spd

250ish

 

What are the circumstances that he believes that it may leak?

 

You can drive a transmission to about 260, but that's really hot. Same with the axles.

Fear of leaking is not a good rationale for killing any chance it has to get cool. The mechanic to me is a fraidycat for lack of a better term.

 

Would it be better to switch to an air cooled rad?

That's all my 18 speed has. It's mounted right behind the trany, not even at the front where it can get cool air

 

I wouldn’t operate it without a cooler. An air cooler works just as well. Circulated trans oil instead of antifreeze. Otherwise replace existing one, if worried about it going bad. I’d leave it alone.If antifreeze levels drop check for a leak. Newer 9, 10 speeds don’t have coolers. I like my trans to stay around 160 degrees. Heat is the enemy

 

Transmission heat exchangers as I call them or water to oil coolers are two fold purpose. 1. The obvious is to extract heat generated from the transmission and transfer it to the engine coolant and out through the main cooling package. 2. The other side of things is to warm the trans oil quick during cold operation to decrease fluid resistance and help with fuel economy. This is the main reason most OEMs chose to run an exchanger vs a oil to air cooler. Fuel savings is king.

Both of these items should be considered when deciding to remove or switch cooler type on a given application. I local truck that is light duty cycle and hauls light would benefit more from the heat exchanger, where a farm truck the hauls heavy and longer trips to generate the trans heat would be just fine with a oil to air cooler.

The threat of coolant contamination inside the transmission is real and it does happen often. The biggest issue is it delaminates the clutch adhesive on the synchro. With extended running it will ruin the bearings in time and a full rebuild will be needed. Even more havoc is done with automated transmissions and the xy shifter is affected. Bad thing is by the time the contamination is noticed visually it's too late. The damage is done.

Best way to monitor is take an oil sample with your engine oil every PM.

 

After any component's oil temp hits 250F its being damaged. Oil breaks down very rapidly at that temperature.

 

I ran mine with no cooler at all for close to a year with no ill effects. I have a guage and saw no real increase in temps. I noticed the difference im the winter though. That was the reason l finally fixed it lol. That was grossing 135-140 everyday so l think you'll be fine grossing 80g.

 

So my oil type cooler does more heating than cooling? It seems to keep trans 20 degrees cooler than engine.