Towing Temp Question

So I got a trans cooler installed on my van and went to test it this weekend.

My trailer is just about 3,000 lbs, I have the 3,500lb tow rating, I have a weight distribution hitch which is supposed to increase the tow rating to 5,000 and tongue weight on my trailer is less than 300lbs I think or thereabouts.

I got paranoid about trans temps reading lots of stuff and so monitored it last time we went camping, the temps quickly got up to 220+ and so we went to a place only about 30mins away and the temps peaked around 240 (they were still climbing slowly but we arrived)

With the cooler I noticed that it cools down way faster when we stop but the temp was still climbing slowly. Probably in about say 30miles of rolling hills it had just gotten up to 220ish

Based on this image I told myself I wanted to see it stop climbing by 220 or I would consider it not a total success. Is that the correct conclusion?

If I was to tow and pull over anytime I hit 220+ and let it cool to like 200 would it just get back up there even faster due to heat soak?

I didn't tow far enough to see if the temp itself would stabilize, but I am not sure if it would eventually stabilize or if it would just keep climbing based on the example of creeping up a little at a time.

Sounds like you need a bigger cooler. What do you have now and how is it plumbed in? Knowing what van we're taking about and what gear it was in might also be helpful.

You definitely need a bigger cooler. Also, if you have the in-rad cooler still connected, aux cooler should go after the aux cooler in the loop, not before.

Also, are you towing in the highest gear you've got or manually forcing it down a gear? Some transmissions will only lock the TCC in the highest gear unless you've locked that gear out, then it'll allow lockup in the next gear down.

If you're climbing hills with the trans downshifting on its own and not locking the TC, you're going to make a crapload of heat.

Agree with the above but if the cooler is plumbed before the radiator cooler then change that first and re-test.

Is too cool a potential problem?

Cooling after the rad seems like over cooling could be possible.

Van is a 2010 Honda Odyssey Cooler is a Derale 8000 model number 13503 https://www.etrailer.com/Transmission-Coolers/Derale/D13503.html

Stock trans cooling runs through the bottom of the transmission, I followed the instructions and checked for which line was warmer and which was cooler, trans cooler is installed on the cooler line which then goes back to the transmission so its already in line.

I did all towing with the van in drive but the little O/D button on the side of the shifter disabled so the dash said D3

I also would not say that the terrain tested was super hilly, it goes up and down a little bit but not huge or long elevation changes.

On the upside I suppose I could keep the same lines and just put a bigger cooler on the front of the AC condenser andnot have to mess with running the lines to/from the stock transmission cooling location

I don't think there is room for a 2" stacked plate cooler, but I could easily fit a larger 7/8" one

Sounds like you just need a bigger cooler then.

Robbie wrote: Is too cool a potential problem? Cooling after the rad seems like over cooling could be possible.

Not much of a concern in most cases. Trans fluid doesn't need to get all that warm. And if it does over-cool the thing in the winter, there are inline thermostats that can be added to help the issue.

Plus, the in-rad cooler is in the cold side of the rad anyway, so under light load in cold weather (or until the engine is fully warm with the t-stat open), that side of the rad is pretty darn cold anyway and can keep the trans pretty cool.

Yeah... way bigger cooler. Yikes. 240..

I have a cooler I bought for my suburban, the biggest that whatever brand it is makes. I then found out about this 45K cooler that can be installed easier using the stock parts. I will message you what it is, I will sell it super cheap as I never even opened the box.

Blaise wrote: Yeah... way bigger cooler. Yikes. 240..

240 was with no cooler

Jaynen wrote:

Blaise wrote: Yeah... way bigger cooler. Yikes. 240..

240 was with no cooler

Yeah I should have clarified. Just saying the 240* is scary.

My truck hangs around 180-190. I'm adding a cooler tonight. Going to be towing to VIR on Friday. Here goes nothing...

With a huge cooler, 160 degree t-stat in the trans cooler lines and the in-rad cooler bypassed, my Jeep sits around 160 - 170 for the most part. Since I put the current (bigger) cooler on, I haven't seen it much over 170. With the previous cooler, it would creep towards 200 (and still slowly climbing) if I really started beating on the thing on a warm day.

I'm not 100% sure my "gauge" method is totally accurate I am using the Torque app to a bluetooth obd dongle with codes that I found online. It is not the same as my coolant temp or tied to coolant temp however

Part of me wants a tow vehicle anyway but its harder to get wife buy in. Even trying another cooler to replace this one is cheap comparatively to most other options