Transmission Cooler

[JeremyFr]

Ok, so I've got a 2002 F150 with the 4.2L V6, I recently ordered a Derale Class IV plate and fin transmission cooler for it.

Everything seems straight forward, any tips, tricks, secrets, or anything else I should know before installing it this weekend?

[PUCampin]

Most of the more recent transmissions have a thermostatic valve, so fluid goes out to the coolers only when it gets above operating temperature, a lot like the engine coolant thermostat. This allows the transmission to quickly reach and maintain proper operating temperature.

This is why the above poster jodeb720 continues to see the temperatures, the transmission is purposely maintaining operating temperature. The extra coolers are useful for high load conditions like climbing and for quick recovery following high load conditions. The 6R75 in my Expy warms to 195 in the driveway under zero load, and then stays there. Both the transmissions and the newer fluids have been designed for this.

This is also why flushes are not as effective on many newer transmissions, to get flow you have to bypass the thermostatic valve, or get the fluid hot enough for it to open, which is very hard without actually driving the car. In my case, the thermostatic valve is inside the case so it cant be bypassed. A flush machine is pointless. Just drain and fill.

One other note, the above post regarding the water oil vs air oil heat exchange is correct. The water oil heat exchange that takes place in the bottom of the radiator is substantial, and it happens no matter how fast the car is moving. The oil air coolers have to be massive to accomplish the same heat transfer as the water oil cooler, and the vehicle has to be moving to create the airflow. If you are pulling a steep grade, or backing into a campsite, those oil air coolers are not effective.

[JeremyFr]

Before the cooler I was seeing 160-175 on flat ground with no load, towing the trailer on grade I hit 198.5 on my monitor which while "safe" was a bit high for my liking.

Now with the Derale in place I see 150-155 on flat ground no load, and saw no higher than 182 on grade and that was just briefly it was averaging 175 on grade with the trailer which is right where I'm comfortable. I don't have a fan on my cooler, but have it same as yours radiator to derale to transmission. The truck still currently has the engine mounted fan but I'll be removing that and adding electric fans in the near future.

[jodeb720]

FWIW,

I have a 16 pass, stacked plate Derale with a fan on my 2003 chevy silvarado 2500HD. The manufacturer had it go from Tranny -> Tranny Radiator Cooler -> Derale -> Tranny.

On flat level ground, when it's 75 or 110, the transmission is 175. When it's on a climb (up to 6500' in 14 miles) it'll get over 220 maximum - but remember, the transmission temperature will also climb way above 225 until the fan kicks in - so that heat is transferred to the Transmission cooler in the radiator - and then to the transmission.

Do I like it? Not a chance. but it's never for a long period of time and I drop the pan, change the filter, and have the transmission fluid changed annually. At 160,000 miles, it's still running strong.

Oh - I always make sure the electric fan is on when I two (via a 30 amp relay) to insure there is the maximum airflow at lower speeds.

Just my two cents.

J

[JeremyFr]

So very happy to report did our first trip since the install, saw an average of 20 degree difference in temp's vs. not having the cooler. Recovery time after grades was a-lot better to. Well worth the work to install it!

[JeremyFr]

Well got it all in today, was a bit of a PITA, at anyrate fab'd a bracket to mount it to, ran the suggested way. It was a Derale class IV plate & fin. I was unsure of putting one in but our last trip the tranny hit 195 pullin up a grade according to the ODBII system and that was a bit too close for comfort for me.

[hotpepperkid]

Mine has only air to oil cooler. Normal on highway not towing is around 140, towing 170 on a cool day not over 100. In town going light to light starts to heat up towing depending on the distance. Not towing on a 110+ day light to light gets up around 200 towing 225. Highway with lots of hills gets up around 180 or so I fixed that put on the oil cooler they put on the PSD 6.0

[marcsbigfoot20b]

j-d wrote:

RLS7201 wrote:
Ideally you want to maintain 160F-180F degrees ATF at all times. Just like your engine, your transmission has and ideal temperature range. Richard

That, my friends, is the Correct Answer. As much as we want to curse "The Engineer Who..." the truth is that when we bet against the engineer we usually lose.

In the Sunny South, I might bypass that in-radiator ATF cooler. Up North, NO. Transmission needs warmth.

Why might I bypass in the South...? Transmission in a Dodge van we had, started missing on shifts, a little engine runaway here and there. Dropped the pan and it looked like mud in the bottom. Wasn't mud, it was rust and ground up transmission. That little cooler had developed pinholes and the radiator pressure cap was enough to push radiator coolant into the transmission. Cheap radiator ruined expensive transmission...

If you're considering bypassing... That Air Over Cooler has to be HUGE! Takes about a couple dozen times the surface area to transfer heat to air, than to a liquid.

Sometimes you can tell before by looking at the upper dipstick area where there is no oil.....just lots of rust.

[j-d]

RLS7201 wrote:
Ideally you want to maintain 160F-180F degrees ATF at all times. Just like your engine, your transmission has and ideal temperature range. Richard

That, my friends, is the Correct Answer. As much as we want to curse "The Engineer Who..." the truth is that when we bet against the engineer we usually lose.

In the Sunny South, I might bypass that in-radiator ATF cooler. Up North, NO. Transmission needs warmth.

Why might I bypass in the South...? Transmission in a Dodge van we had, started missing on shifts, a little engine runaway here and there. Dropped the pan and it looked like mud in the bottom. Wasn't mud, it was rust and ground up transmission. That little cooler had developed pinholes and the radiator pressure cap was enough to push radiator coolant into the transmission. Cheap radiator ruined expensive transmission...

If you're considering bypassing... That Air Over Cooler has to be HUGE! Takes about a couple dozen times the surface area to transfer heat to air, than to a liquid.

[time2roll]

marcsbigfoot20b27 wrote:
Transmission ---> OEM tank cooler in radiator (if present) ---> external fin type cooler ---> back to transmision.

+1 this is how the OEM engineers place auxiliary coolers.

I would have suggested the Ford unit that came with the towing package or even the larger F150-HD cooler and all factory brackets and steel hoses.

Aftermarket is fine too. Just make sure the rubber hoses are well protected and do not rub on anything.

[RLS7201]

Not only does the cooler in the radiator help cool the ATF, it helps keep the ATF up to temperature in the winter time. You can also over cool your transmission in the summer time. Ideally you want to maintain 160F-180F degrees ATF at all times. Just like your engine, your transmission has and ideal temperature range.

Richard

[Tim_Nowicki]

Completely bypassed the cooler in the radiator on my pace arrow. Ran two stacked plate tranny coolers right out front behind the grill. Runs way cooler that way. Been that way for years.

[marcsbigfoot20b]

Transmission ---> OEM tank cooler in radiator (if present) ---> external fin type cooler ---> back to transmision.

[cbshoestring]

Installing an after market tranny cooler is as simple as removing and re-attaching a couple hoses (may involve cutting hard lines). The heardest part is determing which line feeds the cooler, which is the return line. (run the truck the hotter of the two lines feeds the cooler, the cooler one returns to the tranny) You'll need that, BECAUSE............

The debate starts when you research whether or not the additional cooler should be placed BEFORE or AFTER original. Lots of opinions on goggle, either way has the fluid going BACK to the tranny COOLER.

If memory serves me correctly (been a few years---I am getting forgetful)...I installed mine on the old truck directly to the feed coming FROM the tranny. That way the hot fluid was pre-cooled by the additional cooler, before running through the built-in radiator cooler.

[Egor_sRV]

I have read in several sources that the temperature pickup should be mounted in the transmission pan instead of the return line as many of the installation instructions tell you. It is much more accurate even though it does require some drilling and welding to install. I have always done it this way, and hopefully, saved some transmissions along the way.