Ok guys

Seams like I am getting more Guys telling me "not" to run the factory auto trans cooler , on my 1990 12V Cummins (Ford crewcab Project)

All of the local's are telling me stories , about guys who have had the factory cooler on the side of the block, actually fail internally and mix the anti-freez with the trans fliud...hence destroying the trans



So far it is 3 to 1 against running it....Due to the "I know a guy " stuff I am getting locally


I need more opinions please



My cooler has no rust externally...and came out of an airport tug..with very low hours, and has the # 3914759 on the side




Thanks in advance for your time and knowledge

 

hmmm... I would run that oil to water cooler/heater. It will warm the fluid in certain circumstances, and cool in others in series with your air to oil cooler (which SHOULD be upgraded as it is too small).

Water removes heat more than 4 times easier per mass flow rate than the same temperature air cooler. That cooler helps. I wouldn't switch it unless you put on a much bigger cooler, but you may cool your fluid TOO much in certain circumstances.

 

Thank you dzl Damon for the lesson on efficiantcy

I do like the fact that the facory cooler will help to warm the trans up in the winter months here in MI...as I do plan to plow my driveway this winter


But my Main concern in this thread, is the mixing fluids Myth....is it true , or just an isolated occurance I'd hate to loose my 47RH I just put in

 

ive never heard of anything like that???

 

The ones I've heard of failing were leaking coolant externally, I haven't heard of them dumping coolant into the ATF.

It is certainly possible for that to happen, but it's not a common occurrence.

 

I've only heard of issues like this in IH 7.3L IDI motors found in the pre 94 Fords (and maybe later too, but I'm unfamiliar with the Powerstroke). They had a similar heater on the other side of the engine for the engine oil. It would have issues leaking too, but it was assembled different... I think the tube sheet was pressed in the shell and had a large o ring that would go bad.

A rule of heat exchangers is that the more critical medium being cooled (or heated) is under a higher pressure. THat way it will not be contaminated by the other medium. Yes, that means you will eventually run dry, but hopefully you check your fluids everyweek, or check your gauges and see oil pressure going erratic, or tranny temps going up, etc.

My point to my ramble: The ATF should be at a higher pressure than the coolant. Therefor, your leak should flow from the ATF side INTO the coolant, not the other way around. ATF in the coolant would show up in your radiator overflow and not be that big of a deal. But water in your ATF or engine oil is bad news, so they don't design it that way.

 

You better run that heat exchanger or you'll run the risk of ruining your transmission in the winter. It warms the fluid as well as cools it so the transmission get optimal temperatures in climates such as the one you are living in.

Here's what you ask the local-yocal doubters... If it was such a POS why did Dodge use it for years and years? And go price one aftermarket or new, you'll need a change of shorts when you see what they go for. It's a good piece of equipment really, and should be used in conjuction with air to air tranny cooler or coolers, and always run a transmission temp gauge.

 

dad has a similar sized exchanger on our lobsterboat that just cools the engine water with sea water. Costs $1500! Granted it is a marine product, so that automatically adds money, but still... a shell and tube heat exchanger is not cheap.

 

700k on mine never a leak

 

Keep the heat exchanger and run a bypass for the aux cooler so it will flow in the cold.

If it actualy does fail internally you will get ATF in the coolant not the other way around. Cooling system pressure is around 16psi or so and the trans is way higher than that.

 

Thanks guys

I just needed to know from some more people who " actually " own and operate these drivetrains everyday

I apprietiate everyones input and thanks for your time

 

My current rig is a 5 speed but I previously owned a '93 with an auto. Never had a problem with the cooler. Kept the tranny cool in the summer and help warm it in the winter. In fact the Coolant temp was more steady with an auto and the heat exchanger when I pulled the fan for the winter than on my 5speed.

BTW That truck saw temps anywhere from -60* to 100*.

 

It will mix both ways. When you shut the truck off the trans pressure is zero and the coolant system is still under pressure. Guess where the pressure bleeds off to?

If you are in cold climates running the heat exchanger is not a bad idea as it will warm the fluid, and, as was earlier posted is a lot more efficent at cooling than the air to air types.

It is rare but it does happen that the heat exchanger cracks internally and allows trans fluid and antifreeze to mix. Even the 3rd gens have the same type of cooler and will suffer the same problem. Truthfully, its no more prevalent than mixing engine oil and coolant when the oil cooler cracks which they will do on occasion.

 

True.......

 

Is there a way to prevent this from happening...and additive for protection maybe ??



Thanks guys