Toyota Sienna Forum - siennachat.com banner

1 - 16 of 16 Posts

·
Registered
Joined
·
13 Posts
Discussion Starter #1
my question is whether a transmission cooler is needed to haul with this van. The tow prep package has the heavy duty radiator so is this enough for towing?
 

·
Registered
Joined
·
356 Posts

Attachments

·
Registered
Joined
·
13 Posts
Discussion Starter #5
It is cheap insurance to keep the tranny in good shape. I also installed a magnefine filter on the return line that is going back to the tranny.

https://smile.amazon.com/gp/product/B0787KWZPS/ref=oh_aui_search_asin_title?ie=UTF8&psc=1

I also used a Hayden 678 tranny cooler.

ordered that as well. I have ordered the Derale 8000 transmission cooler as well as the Derale Fluid Control Thermostat Kit so that in winter time my transmission will eventually warm up being that we live in Canada. thanks for the help
 

·
Registered
Joined
·
356 Posts
ordered that as well. I have ordered the Derale 8000 transmission cooler as well as the Derale Fluid Control Thermostat Kit so that in winter time my transmission will eventually warm up being that we live in Canada. thanks for the help
Sounds like you will be all set!!! Living in the southwest, I generally don't worry about cold weather. lol
 

·
Registered
Joined
·
92 Posts
ordered that as well. I have ordered the Derale 8000 transmission cooler as well as the Derale Fluid Control Thermostat Kit so that in winter time my transmission will eventually warm up being that we live in Canada. thanks for the help
Be careful with this Thermostat Kit. I've heard a lot of bad reviews about it - e.g. Derale 25719


Best regards



Pelos
 

·
Registered
Joined
·
152 Posts
I recently installed a Derale trans cooler on my 2018 sienna. I’m not sure if the hose sizes are the same on yours, but the “universal” adapter that came with the kit didn’t seal well to the factory hose...I was able to get it to stop leaking by really tightening the hose clamps, but didn’t feel great about it. I ended up buying a different adapter (Derale part for GM/Buick applications). I will tey to get the part number. It works much better in my case. I will warn that if you go that route. Install the small end I to the trans cooler hose first....the barbed end fits into the factory hose a little looser, so if you put it in first, it has a tendency to slip further into the hose when you try to push the other end into the aftermarket hose. If that makes sense...


Also I absolutely needed an additional 4 feet of hose for my install.

One last thought on the trans thermostat...you could consider buying the factory thermostat for a 2017/2018 sienna. Probably not cheap, but almost certainly will be reliable.
 

·
Registered
Joined
·
13 Posts
Discussion Starter #10
does anyone have two radiators on their sienna already? I noticed that mine has two factory radiators. One is clearly engine and transmission and the other one is something else. Does anyone know what the second one is cooling?
 

·
Registered
Joined
·
356 Posts
does anyone have two radiators on their sienna already? I noticed that mine has two factory radiators. One is clearly engine and transmission and the other one is something else. Does anyone know what the second one is cooling?
It is the AC condenser
 

·
Registered
Joined
·
13 Posts
Discussion Starter #13
thanks everyone for all your help. as of today I have a functioning and leak tested transmission cooler and thermostat running in series with the original transmission cooler. Very excited to get out for some camping now!
 

·
Registered
Joined
·
10 Posts
Does the 2017 sienna LE comes with tranny cooler standard? How much weight you are hauling would you start thinking installing one? Thanks.
 

·
Registered
Joined
·
5 Posts
After I had my 2008 Sienna's transmission rebuilt, the guy at the shop highly recommends a transmission cooler. Of course, he also said a Sienna's not a great towing vehicle so keep the weight of trailer low.
 

·
Registered
Joined
·
152 Posts
Does the 2017 sienna LE comes with tranny cooler standard? How much weight you are hauling would you start thinking installing one? Thanks.
When I was researching my vehicle (2018 AWD) I recall coming to the conclusion that all 2017/2018 Siennas came with the tow package standard. This includes an engine oil cooler, larger radiator* and transmission cooler.

*it may just be a higher capacity cooling fan, and the radiator itself may or may not be different. Not sure.

In any case you probably have the tow package already. You can confirm it by looking for the presence of an engine oil cooler - there are a few posts floating around that discuss this (with helpful pictures). I believe fibber2 posted something, so search for that.

As far as needing one or not, It probably depends on your towing usage and conditions. Hot summer, fully loaded, full throttle up a 6% grade? Yes, probably a good idea. Lightweight trailer going a moderate speed on level ground...probably not necessary.

I recently installed a cooler on my 2018, and in the process learned that the factory thermostat for the trans fluid runs at a pretty high temp. Seemed like it was designed to run in the 190-200 range....so the conventional advice of “keep the transmission temps below 190, and shoot for 170” don’t really apply for this transmission. Don’t forget that this modern transmission uses synthetic ATF, so it’s a different beast than the 1980s domestic trucks that the “rule of thumb” advice is likely based on.

If you decide that you need or want a trans cooler, you might find this recent post helpful:

https://www.siennachat.com/forum/69-mods-projects-gen-3/60499-2018-transmission-cooler.html
 
1 - 16 of 16 Posts
Top