Bypass radiator when installing Derale kit?

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LJ FlexN

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I am getting ready to order a Derale tranny cooler kit for my 04 LJ. I have read write ups of the install and of reviews praising the cooler. If my thoughts are wrong on this please correct me, I know you folks will, lol. Wouldn't it make sense to bypass the radiator coolant lines and just use the Derale system considering the coolant temps should be around 210° by design and I am looking to stay below 180° with the transmission temps?
Unless there is a reason not to bypass the radiator lines couldn't I just use the lines at the transmission since it looks like most people mount the cooler on the driver's side frame rail and the inlet/outlet are right there?
 
I bypassed mine and my temps stay below 170. And my sender is at the hot line out so my pan temp should be even less. I see no benefit to sharing engine heat with the trans or vice versa really. It all runs warm enough.

I am no transmission expert, so please don’t take this as gospel.

I do know the 42 rle runs too warm, needs proper gears, needs the overdrive off when loaded, towing or long incline, needs a cooler and needs proper service intervals and a temp gauge via the pan is not a bad idea.

Avoid silicone when servicing the pan- use a real gasket. A piece got in my valve body and killed mine with under 58,000 miles.
 
LJ FlexN said:
I am getting ready to order a Derale tranny cooler kit for my 04 LJ. I have read write ups of the install and of reviews praising the cooler. If my thoughts are wrong on this please correct me, I know you folks will, lol. Wouldn't it make sense to bypass the radiator coolant lines and just use the Derale system considering the coolant temps should be around 210° by design and I am looking to stay below 180° with the transmission temps?
Unless there is a reason not to bypass the radiator lines couldn't I just use the lines at the transmission since it looks like most people mount the cooler on the driver's side frame rail and the inlet/outlet are right there?
Click to expand...

No, you’re adding an auxiliary cooler. Get a temp gauge and sender so you know what’s going on. Derale was praised especially by someone who didn’t have a temp gauge, so we really know nothing.
 
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I added a gauge a couple of weeks ago and I have seen temps climb up to 200°. I would like to keep them around 170° - 180° is why I am looking into a cooler.
 
LJ FlexN said:
I am getting ready to order a Derale tranny cooler kit for my 04 LJ. I have read write ups of the install and of reviews praising the cooler. If my thoughts are wrong on this please correct me, I know you folks will, lol. Wouldn't it make sense to bypass the radiator coolant lines and just use the Derale system considering the coolant temps should be around 210° by design and I am looking to stay below 180° with the transmission temps?
Unless there is a reason not to bypass the radiator lines couldn't I just use the lines at the transmission since it looks like most people mount the cooler on the driver's side frame rail and the inlet/outlet are right there?
Click to expand...

Why have you decided on a Derale? You are much better off running a decent trans cooler in front of the radiator.

I ran a Derale for a while on my ‘04 LJ, but it was because I ran a supercharger with an air to water cooler in front of the radiator, and had no room there for a tranny cooler. Did it help, yes, a bit. Occasionally saw temps approaching 200 with it, sometimes a bit more.

After losing the supercharger, I got rid of the Derale and now run a much bigger cooler in front of the radiator. Different situation now, but it works much better than the Derale. Rarely do I see anything over 170, and my current setup puts out a hell of a lot of heat.

Also, the Derale is subject to damage under the rig. I built a cage for mine, and tucked it up under the tub, but still worried about getting a stick or something similar up there and puncturing the cooler. That would ruin your day quickly. But locating it in a safer place sacrifices airflow.

Finally, I would never, ever run that Derale cooler in the location they recommend. At least the way I wheel, it would not last one trip.
 
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AndyG said:
I bypassed mine and my temps stay below 170. And my sender is at the hot line out so my pan temp should be even less. I see no benefit to sharing engine heat with the trans or vice versa really. It all runs warm enough.
Click to expand...
The radiator trans cooler acts as a buffer. The aux should be just that, a helping cooler after the primary in the radiator. Radiator cools it some, aux handles the rest and when it is cold, the radiator cooler warms it up, by design.
AndyG said:
Avoid silicone when servicing the pan- use a real gasket. A piece got in my valve body and killed mine with under 58,000 miles.
Click to expand...
I will never use a gasket on any trans pan with the exception of the factory lube locker style on the 32. The better warning would be not to be stupid and slather that shit all over the sealing flange like your brother-in-law sells it for a living. I've installed dozens of 42 pans without a single issue and you still have to get the RTV out to seal that one pan bolt at the threads on the left side anyway. 1/8" bead, spread it out flat to 1/16" thick, bolt it up and it won't be a problem.

I do have a question for your trans guy. How did the silicone piece get past the filter? Makes me ponder if someone was inside the valve body and used some RTV where they shouldn't have??
 
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mrblaine said:
The radiator trans cooler acts as a buffer. The aux should be just that, a helping cooler after the primary in the radiator. Radiator cools it some, aux handles the rest and when it is cold, the radiator cooler warms it up, by design.

I will never use a gasket on any trans pan with the exception of the factory lube locker style on the 32. The better warning would be not to be stupid and slather that shit all over the sealing flange like your brother-in-law sells it for a living. I've installed dozens of 42 pans without a single issue and you still have to get the RTV out to seal that one pan bolt at the threads on the left side anyway. 1/8" bead, spread it out flat to 1/16" thick, bolt it up and it won't be a problem.

I do have a question for your trans guy. How did the silicone piece get past the filter? Makes me ponder if someone was inside the valve body and used some RTV where they shouldn't have??
Click to expand...

All well noted- not sure and maybe was some type of gasket material- he just discovered a clog - I figured sloppy too and wondered the same thing on filter.

For whoever asked the question please note Blaine indicates to keep the one from the factory live-
 
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AndyG said:
All well noted- not sure and maybe was some type of gasket material- he just discovered a clog - if figured sloppy too and wondered the same thing on filter.
Click to expand...
Regardless, if the filter can't stop crap from clogging up the fluid circuits, then why is it there since that is the only job it has to do? You gotta wonder who was in there for what reason to cause something like that to happen.
AndyG said:
For whoever asked the question please note Blaine indicates to keep the one from the factory live-
Click to expand...
 
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NashvilleTJ said:
Why have you decided on a Derale? You are much better off running a decent trans cooler in front of the radiator.

I ran a Derale for a while on my ‘04 LJ, but it was because I ran a supercharger with an air to water cooler in front of the radiator, and had no room there for a tranny cooler. Did it help, yes, a bit. Occasionally saw temps approaching 200 with it, sometimes a bit more.

After loosing the supercharger, I got rid of the Derale and now run a much bigger cooler in front of the radiator. Different situation now, but it works much better than the Derale. Rarely do I see anything over 170, and my current setup puts out a hell of a lot of heat.

Also, the Derale is subject to damage under the rig. I built a cage for mine, and tucked it up under the tub, but still worried about getting a stick or something similar up there and puncturing the cooler. That would ruin your day quickly. But locating it in a safer place sacrifices airflow.

Finally, I would never, ever run that Derale cooler in the location they recommend. At least the way I wheel, it would not last one trip.
Click to expand...

Second this, I'll be pulling my derale and swapping in a Setrab when I can.
 
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Apparition said:
https://www.amazon.com/dp/B07C64FTTK?tag=wranglerorg-20

Setrab works better and the derale is obnoxiously loud.
Click to expand...
In slow crawling, I think the Derale has a slight edge. Anything other than that scenario, the Setrab we use is far more effective. And so we don't confuse folks that might miss the link, the one we use is from the Slimline race series. 53-10748
That series is a radiator style with none of the fancy BS, just a plain, simple, very effective design.
 
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I appreciate everyone's input and advice. I ordered the Setrab that @Apparition linked earlier. Looks like it is an 53 - 10748 - 01 proline SLM. Looks like it is the same one that @mrblaine said he uses.
Any time saving tips for when I go to install this thing in a few days when it gets delivered?
 
LJ FlexN said:
I appreciate everyone's input and advice. I ordered the Setrab that @Apparition linked earlier. Looks like it is an 53 - 10748 - 01 proline SLM. Looks like it is the same one that @mrblaine said he uses.
Any time saving tips for when I go to install this thing in a few days when it gets delivered?
Click to expand...

It’s much easier to install the Derale…

😬

But the result is worth having to pull the radiator and welding a bracket to the V support…
 
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LJ FlexN said:
I appreciate everyone's input and advice. I ordered the Setrab that @Apparition linked earlier. Looks like it is an 53 - 10748 - 01 proline SLM. Looks like it is the same one that @mrblaine said he uses.
Any time saving tips for when I go to install this thing in a few days when it gets delivered?
Click to expand...

You will need some more parts, hoses, etc... I plan on following what JMT has done which is inline with what @mrblaine does. I can't recall but I think there are some somewhat specialized fittings used to make connections easier. Read through JMT's build it has some good photos and discussions.
 
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