Transmission Cooler

I just purchased a 2019 4Runner Limited. I plan on towing a 21 foot Escape travel trailer. The total dry weight of this trailer is 3210#. But a real world estimate once it has been accessorized and packed might be more like 4200#.

I know I'm close to the edge using the 4Runner as a tow vehicle. That said I'm wondering if it comes with a transmission cooler like the Highlander does. If not would it make sense to install one. Thanks.

 

It’s got one but I recommend adding a larger one with an electric fan.

 

The 4Runner has a "sort of" trans cooler like every vehicle does. The trans fluid is routed into a separate circuit of the radiator. This is not as effective as a dedicated trans cooler because the trans fluid is also getting heat from the radiator fluid. It is believed that if you tow a lot or heavy loads that you need a separate, dedicated trans cooler. The 4 used to come with dedicated trans coolers (4th gen) but Toyota either eliminated this due to budget concerns or found it doesn't really need it. My guess, it doesn't really need it. The Toyota engineers know what they are doing and if it needed it I believe it would have come with it.. But maybe I'm dumb and trust Toyota TOO much.

I actually bought a separate cooler cuz I was worried about my trans at one time but still have not installed it due to the warranty. I asked the dealer if they would install it for me and they said no, putting in an aftermarket cooler voids your warranty. When the warranty ends I may install it. Until then I will drain and fill the fluid every 50K for good measure. I tow a lot but not too heavy.

Adding a cooler with a fan is nice but really only necessary if you are doing low speed things or if you are mounting the cooler in a remote place where there won't be a lot of air moving over the cooler. If I put a dedicated cooler in it, it will be in front of the radiator so the engine fan will pull air through it at all times.

 

This was a very helpful response. Thanks. I definitely do not want to void the warranty. You wrote that "you tow a lot but not too heavy". Can you be more specific about the weight of the trailer that you are towing?

 

Sure, it's a 5x10 Big Tex utility trailer and I mostly tow dirt bikes on a regular basis with all our gear. Usually two bikes, sometimes three. One time I moved some dirt on it for a short distance. It was a lot of weight but that was a short distance and a one time deal. Have done Home Depot runs, lumber, bags of concrete, etc... Also I have a M416 military trailer but it is currently at the fabricator getting some work done. The 4 has handled it all very well considering the soft suspension. I have been contemplating putting air bags on it to help when towing more weight. My 4 has stock suspension.

 

Okay. I have the Limited Edition and couldn't be happier with this purchase. I am going to install a Tekonsha Prodigy P3 Trailer Brake Controller before I pick up the Escape trailer in May. This is a double axle trailer so I don't think I'll need an equalizer hitch with sway control included.

 

I have that same brake controller. It works well and was easy to hook up with the factory harness.

 

Which tranny line is hot hose. Direction of flow.

 

When the vehicle is cold find both trans lines. Crank the engine go through the gears a few times then climb under and feel the two lines again. The hotter of the two will be the hot or outlet from trans. If that fails pop both hoses off the radiator and have some one start the engine the one that shoots atf is the hot/outlet from trans.

 

I know it's winter here but after having my scan gauge hooked up to the vehicle for a while now my trans temps have not gotten above 155 degrees. That's towing or any other situation. So far I am not going to install the trans cooler I bought until I see a need to do so. We will see what the summer brings but, Why open up another area of failure if I don't have to?

 

yes when towing having the scan gaugeII is IMO the tool to use .. so I have not used the Toyota towing , but in the hot temps the tranny gets to 185F.. so since it is below 200F no problem.
I use my GM truck to tow my 20FT boat . loaded up it must be 4500lbs .. the scan gauge II indicates 190F in summer temps 80-90f ..gm truck also has a OEM cooler with the tow PKG ..