Transmission cooler tester needed

[mrblaine]

We've all been watching the struggles trying to find a particular Setrab cooler and I have a vested interest in them being supplied again since they work very well with a few of my products. In the meantime and in case they never come back in stock, I'm working on a couple of substitutes. I've found a couple that are similar in size in a design that works well for other stuff, we just need to prove it.

So, do you work your 42RLE hard, live where it is hot, and are interested in working harder than you need to for an AB swap? I'll cover all the parts and you need to have the Setrab 53-10748 installed now and then drive in similar known conditions with your existing temp gauge telling us if we are close or we need to toss that piece of shit in the trash and start over.

The good news is if this works, the retail for the cooler will be around 140 ish.

 

[rasband]

If you haven't found anyone yet, I can do it. I haven't installed my setrab, but the last couple trips are showing me I need to and could provide readings on the same trail with OEM, Setrab, and your new candidate. I'll call you tomorrow morning to check in.

 

[Irun]

FWIW, I ran a Setrab 53-10748 in my LJ and have a B&M 70264 Supercooler in the TJ. Having driven them both extensively, back-to-back, what I noticed was this:

- On the road, for daily driving, the temperatures differences between the two were marginal. For example, I have a path I drive routinely, 5 days a week. On that path, picking a 90-degree day as a scenario, the B&M cooler would run between 148 to 153 degrees. The Setrab cooler, under the same conditions, would run about 5 degrees cooler.

Offroad, the temperature difference was dramatically different. On long steep climbs with the B&M cooler I'd see temperatures peak at around 183+ degrees. With the Setrab cooler, under the same conditions, the transmission temperatures were at least 20 degrees cooler.

I'm guessing you've already thought about this, so just throwing out some practical data I've seen.

If you don't find someone, I'd also be willing to help test.

 

[mrblaine]

FWIW, I ran a Setrab 53-10748 in my LJ and have a B&M 70264 Supercooler in the TJ. Having driven them both extensively, back-to-back, what I noticed was this:

- On the road, for daily driving, the temperatures differences between the two were marginal. For example, I have a path I drive routinely, 5 days a week. On that path, picking a 90-degree day as a scenario, the B&M cooler would run between 148 to 153 degrees. The Setrab cooler, under the same conditions, would run about 5 degrees cooler.

Offroad, the temperature difference was dramatically different. On long steep climbs with the B&M cooler I'd see temperatures peak at around 183+ degrees. With the Setrab cooler, under the same conditions, the transmission temperatures were at least 20 degrees cooler.

I'm guessing you've already thought about this, so just throwing out some practical data I've seen.

If you don't find someone, I'd also be willing to help test.

Marginally helpful since you would struggle to get a steering cooler over the 70264 without removing the hood safety latch. In all likelihood, that means an appropriately configured B&M offering BELOW a log style steering cooler would have to be tested to be valid.

I will only do an AB comparison between the coolers in the same vehicle under very similar conditions. Otherwise we wind up with bullshit speculation and observational misunderstandings that seem to be taking over this place.

I'm am not going to deal with someone trying to invalidate my/our findings by saying that the new cooler was in an orange rig and the Setrab was in a blue rig and that's why the new one works better.

 

[NskLJ]

We've all been watching the struggles trying to find a particular Setrab cooler and I have a vested interest in them being supplied again since they work very well with a few of my products. In the meantime and in case they never come back in stock, I'm working on a couple of substitutes. I've found a couple that are similar in size in a design that works well for other stuff, we just need to prove it.

So, do you work your 42RLE hard, live where it is hot, and are interested in working harder than you need to for an AB swap? I'll cover all the parts and you need to have the Setrab 53-10748 installed now and then drive in similar known conditions with your existing temp gauge telling us if we are close or we need to toss that piece of shit in the trash and start over.

The good news is if this works, the retail for the cooler will be around 140 ish.

I just ordered the Sertrab today, Jegs said back ordered till August 25th.

 

[bty34]

I just ordered the Sertrab today, Jegs said back ordered till August 25th.

Don't make plans based on that date. Jegs gave a 5/21 delivery when I ordered mine on 3/13. July 16 they updated it to 9/24. I'm not in a hurry and can wait until they eventually fulfill it or a better option comes along.

 

[NskLJ]

Don't make plans based on that date. Jegs gave a 5/21 delivery when I ordered mine on 3/13. July 16 they updated it to 9/24. I'm not in a hurry and can wait until they eventually fulfill it or a better option comes along.

Thank you for the info. I ordered hydro assist and was going to do the trans cooler at the same time. I may have to make other plans I guess or do the steering and move the aux trans cooler.

 

[Sudo]

@mrblaine - Any luck finding a tester to help support this project? With continued slipping delivery dates of the Setrab, I am also very interested in learning about potential alternatives to the setrab that many have successfully used here. I still have hopes that September we will see more but as they say, ..."hope is not a plan."

Thanks for pursuing alternative solutions to this problem.

 

[rasband]

I am trying to wrap up getting the data from the OEM (done) and Setrab (TODO) tomorrow or the next day to at least get a baseline. Some family (back to school and a foot injury) stuff slowed me down unfortunately (my apologies to those waiting).

 

[NashvilleTJ]

I am trying to wrap up getting the data from the OEM (done) and Setrab (TODO) tomorrow or the next day to at least get a baseline. Some family (back to school and a foot injury) stuff slowed me down unfortunately (my apologies to those waiting).

I hope the injury was not too bad, Matt.

 

[Apparition]

I hope the injury was not too bad, Matt.

Probably got hit by a mountain biker out on the trail.

 

[mrblaine]

@mrblaine - Any luck finding a tester to help support this project? With continued slipping delivery dates of the Setrab, I am also very interested in learning about potential alternatives to the setrab that many have successfully used here. I still have hopes that September we will see more but as they say, ..."hope is not a plan."

Thanks for pursuing alternative solutions to this problem.

We do have a tester and he is working on getting a decent baseline of what temps the trans is creating during normal driving sans any aftermarket coolering. Oddly, his are slightly different than what we are used to seeing around here. We see more heat on the highway than he is seeing. But, at least it will be a good baseline.

I have no high hopes for the couple of coolers I've found. There are two types, bar and plate and extruded tube and fin. If neither of them produce the results we are after and barring a timely delivery of the delightful Setrab product, I may enter into negotiations with this company and see if I can convince them to produce something for me that fits. I like their science, I'm fond of the appearance, whether we can get something that works remains to be seen.

https://deltapag.com/products/oil-cooler

 

[NashvilleTJ]

We do have a tester and he is working on getting a decent baseline of what temps the trans is creating during normal driving sans any aftermarket coolering. Oddly, his are slightly different than what we are used to seeing around here. We see more heat on the highway than he is seeing. But, at least it will be a good baseline.

I have no high hopes for the couple of coolers I've found. There are two types, bar and plate and extruded tube and fin. If neither of them produce the results we are after and barring a timely delivery of the delightful Setrab product, I may enter into negotiations with this company and see if I can convince them to produce something for me that fits. I like their science, I'm fond of the appearance, whether we can get something that works remains to be seen.

https://deltapag.com/products/oil-cooler

If you were able to come to an agreement with these folks to build a custom cooler, would you make any changes compared to the design of the Setrab?

 

[mrblaine]

If you were able to come to an agreement with these folks to build a custom cooler, would you make any changes compared to the design of the Setrab?

I can work around most things but the top/bottom facing ports complicate plumbing in our limited space. I'm pretty sure in use, they need to be mounted on the top or risk an air lock. Or at least we've run into that with the Setrab when the upper port is used as the inlet.

But, I'm not going to spend too much time speculating until we get an idea where we are with the other stuff. I can buy them at about the same price as that one in small quantities. What I'm looking to avoid is what we have now with the Setrab and what Derale did. They discontinued our steering cooler. Fortunately, I was able to get in touch and find remaining stock on hand. Unfortunately I now have a couple hundred of them in stock whereas previously, 50 at a time was plenty to last awhile.

That said, what do you think needs to be changed?

 

[NashvilleTJ]

I can work around most things but the top/bottom facing ports complicate plumbing in our limited space. I'm pretty sure in use, they need to be mounted on the top or risk an air lock. Or at least we've run into that with the Setrab when the upper port is used as the inlet.

But, I'm not going to spend too much time speculating until we get an idea where we are with the other stuff. I can buy them at about the same price as that one in small quantities. What I'm looking to avoid is what we have now with the Setrab and what Derale did. They discontinued our steering cooler. Fortunately, I was able to get in touch and find remaining stock on hand. Unfortunately I now have a couple hundred of them in stock whereas previously, 50 at a time was plenty to last awhile.

That said, what do you think needs to be changed?

Nothing I have in mind, but I've installed exactly one - so I don't know what I don't know. The Setrab certainly works well for my needs and install requirements (thanks to you).

But maybe powder coat 'em Yellow...

 

[mrblaine]

Nothing I have in mind, but I've installed exactly one - so I don't know what I don't know. The Setrab certainly works well for my needs and install requirements (thanks to you).

Well, maybe next time I can figure out a way to do a good enough job that you actually mention where you got it when you are showing it off.

But maybe powder coat 'em Yellow...

You act like I lack the ability to actually do that. Trust me, I'm not without them. Powdercoated yellow grill just to see if I could.

 

[NashvilleTJ]

Well, maybe next time I can figure out a way to do a good enough job that you actually mention where you got it when you are showing it off.

…

Point taken.

 

[rasband]

A huge thank you to @mrblaine for providing all of the hardware I was missing and a few extras. I have had the setrab and a small assortment of components sitting on the shelf for a couple years since I wasn't using the Jeep much and was going to install it the previous way (welding to the OEM V-bar), but since the steering cooler design has changed - so have the installation directions, which is how we will be running these all in nearly the same configuration.

Here's the testing conditions and methodology (my kids helped as a science experiment) that each cooler will see:

• A/C on the 3rd dot, face only (no recirc)
• Overdrive Off
• Stick to the speed limit so we can closely repeat the load characteristics
• Collect data every ~2:30
• Assume the engine/trans temp starts somewhere near ambient
• Assume ambient is roughly constant
• Transmission temperature sensor is a brazed bung into the pan - this gives us operating temperature, and read off this gauge (again thanks to @mrblaine a few years ago)
• Engine temperature is estimated off the dash
• 2 High
• Jeep Variables:
  • 5.13 Gears
  • Roughly similar weight in the vehicle across tests (my fat ass, trail doors, soft top, spare tire, backseat)
  • Radiator: Denso 221-9234

And the drive cycle:

• 10 minute idle warmup
• drive to the nearest highway with a decent climb
• drive until we plateau (or back off the highest temp for more than a couple collection intervals)
  • This wasn't enough, so OEM #2 (and later tests are a longer drive loop totaling ~1:30 of driving composing highway and city driving)

Obviously with how these gauges are designed, there's some amount of estimation involved - however I did my best to get close to what should be accurate given the hash marks. If I am off, I should be consistently off the same way .

One notable omission on my part, I didn't have a chance to get to any 4 low trails, but I think that is okay - as you will see in the "around town" numbers in OEM #1.

This rough elevation profile is on the drive cycle in OEM #2 and after.

OEM (test #1):​

There's a few curious things about this to me. I was expecting highway driving to get higher than this, especially at my altitude due to the thin air.

This is only the formalized data collection window. After this plateau I pulled off the highway and ran over to a buddy's. Climbing into his neighborhood I saw nearly 230°F. On my way home I had to run to the big orange for some drywall mud and took the surface streets. Consistent ~230°F most of the way there and home. This is very not good.

Jeep gave 220° as the upper end of safe, which I'd still like to avoid. Anecdotally - I didn't see numbers this high when I was in Moab in 2025 (I paid slight attention since I had the setrab on the shelf), but did get closer in Sand Hollow (one change I did make in Sand Hollow was adding a little more ATF for the steep climbs when I'd lose some engagement - so perhaps slightly overfull, but that's unavoidable for steep climbing rigs).

Due to the follow up anecdotal observations above, I am considering this test incomplete. Jump to OEM (test #2) for a better sampling.

OEM (test #2):​

The only notable change for this run is a decrease in ambient temperature of 3-4° - which appears to only delay the same behavior. Perhaps larger temperature changes affect this more dramatically, but this feels like a good confirmation of OEM #1 with a longer tail end of city driving.

Some annotations to this chart:

• 0-10m: Warm up (same as above)
• 10-17:30: City-ish
• 17:30-42:30: Highway (mixture of climbs and moderate)
• 42:30+: City

Once I get the Setrab in I will follow up with the same methodology as the OEM #2 run.

 

[rasband]

I hope the injury was not too bad, Matt.

Thanks Jeff. I have had some inflammation issues in my foot on and off for a year or so. Some times it's nearly immobilizing, which is awful and I am way too young for.

There's no definitive answers yet, but this next go around is a focus on low/no/anti-inflammatory foods while I get back in the shape I gave up back when I broke my shoulder and ribs mountain biking before my daughter was born (a funny history about me is I've broken at least a few bones only a few months before each of my kids were born).

Getting back from way too sedentary to active is way harder than just staying active in the first place. Long story short, I'm pretty sure this is my own damn fault.

 

[mrblaine]

A huge thank you to @mrblaine for providing all of the hardware I was missing and a few extras. I have had the setrab and a small assortment of components sitting on the shelf for a couple years since I wasn't using the Jeep much and was going to install it the previous way (welding to the OEM V-bar), but since the steering cooler design has changed - so have the installation directions, which is how we will be running these all in nearly the same configuration.

Here's the testing conditions and methodology (my kids helped as a science experiment) that each cooler will see:

• A/C on the 3rd dot, face only (no recirc)
• Overdrive Off
• Stick to the speed limit so we can closely repeat the load characteristics
• Collect data every ~2:30
• Assume the engine/trans temp starts somewhere near ambient
• Assume ambient is roughly constant
• Transmission temperature sensor is a brazed bung into the pan - this gives us operating temperature, and read off this gauge (again thanks to @mrblaine a few years ago)
• Engine temperature is estimated off the dash
• 2 High
• Jeep Variables:
  • 5.13 Gears
  • Roughly similar weight in the vehicle across tests (my fat ass, trail doors, soft top, spare tire, backseat)
  • Radiator: Denso 221-9234

And the drive cycle:

• 10 minute idle warmup
• drive to the nearest highway with a decent climb
• drive until we plateau (or back off the highest temp for more than a couple collection intervals)
  • This wasn't enough, so OEM #2 (and later tests are a longer drive loop totaling ~1:30 of driving composing highway and city driving)

Obviously with how these gauges are designed, there's some amount of estimation involved - however I did my best to get close to what should be accurate given the hash marks. If I am off, I should be consistently off the same way .

One notable omission on my part, I didn't have a chance to get to any 4 low trails, but I think that is okay - as you will see in the "around town" numbers in OEM #1.

This rough elevation profile is on the drive cycle in OEM #2 and after.

View attachment 704134

OEM (test #1):​

There's a few curious things about this to me. I was expecting highway driving to get higher than this, especially at my altitude due to the thin air.

This is only the formalized data collection window. After this plateau I pulled off the highway and ran over to a buddy's. Climbing into his neighborhood I saw nearly 230°F. On my way home I had to run to the big orange for some drywall mud and took the surface streets. Consistent ~230°F most of the way there and home. This is very not good.

Jeep gave 220° as the upper end of safe, which I'd still like to avoid. Anecdotally - I didn't see numbers this high when I was in Moab in 2025 (I paid slight attention since I had the setrab on the shelf), but did get closer in Sand Hollow (one change I did make in Sand Hollow was adding a little more ATF for the steep climbs when I'd lose some engagement - so perhaps slightly overfull, but that's unavoidable for steep climbing rigs).

Due to the follow up anecdotal observations above, I am considering this test incomplete. Jump to OEM (test #2) for a better sampling.

View attachment 704199

OEM (test #2):​

The only notable change for this run is a decrease in ambient temperature of 3-4° - which appears to only delay the same behavior. Perhaps larger temperature changes affect this more dramatically, but this feels like a good confirmation of OEM #1 with a longer tail end of city driving.

Some annotations to this chart:

• 0-10m: Warm up (same as above)
• 10-17:30: City-ish
• 17:30-42:30: Highway (mixture of climbs and moderate)
• 42:30+: City

View attachment 704201

Once I get the Setrab in I will follow up with the same methodology as the OEM #2 run.

I still think you're silly for undertaking this much effort for no benefit to yourself other than knowledge so I really appreciate it. Having done this locally with an improperly geared rig and then after regearing, what may be contributing to lower temps than we expected is the correct gearing.

I've seen lots of shops back east on FB telling everyone that 3.73 and 37's are just fine. I suspect if the owners ever installed a decent temp gauge, there would be some interesting discussions between them and the shop owners.