3rd gen Transmission Cooler Upgrade

Thanks….

 

@b1er and @Kane50 thanks for the install pics! Looks great!

 

Hard to tell by photos, but is theres still room to run a fan between the cooler and rad?

 

It'd have be a thin one... There's not a bunch of room back there with the cooler... or space the bracket and cooler out some and lose the bottom right bolt and trim the bracket, drill another hole in the core support... it could work.

 

Also, a trans temp update... T2 will see 180-185, the T1 temp stays below 160 in 90 degree ambient. the t-stat is pinned for the moment for testing.. the truck is stock, OTT tuned, 265-70-17's... no extra weight except for my fat ass...

 

Yeah I might have to look at moving it outwards some. I'll be doing towing through mountains, so the ability to run a fan would be ideal.

 

Just placed an order for the bracket and

$52 Hayden 678 Universal Rapid-Cool 9.5” x 11” Add-On Transmission Cooler – Not for Direct Replacement of the OE Cooler

Hayden 678 kit for use with the factory cooler. Hopefully this helps with the hot summers in AZ.

I might try the drill and grommet method here. The install looks clean.

edit: ordered the clamps too

 

I'm wondering if I should have ordered the 698 bypass version instead of the 678?

 

@Iconic_

Thank you for letting me change the order to the 698.

 

I posted this in here as well: https://www.tacomaworld.com/threads...l-toyotas-write-up-with-many-pictures.526283/


Is a bypass cooler absolutely necessary in cold climates? I live in MN, we will see -20f temps often enough.

I ordered a

$59 Hayden 679 Universal 11” Rapid-Cool Add-On Transmission Cooler to Enhance Cooling (not for direct replacement of the factory unit)

Hayden 679 and have it mounted but no lines run to it yet, but now after reading more I'm second guessing for a 698 or 699 with bypass.

My understanding is the 3rd gen with tow package has a warmer system at the tstat that utilizes coolant to warm the trans oil (all pre-cooler system). The tstat doesn't open and circulate oil through the coolers until ~187deg, so my original thought was a bypass at the cooler wasn't needed since it should already be at least 187deg, and in my head this still makes sense, but seeing everyone with reports of sub 180 temps makes me second guess everything.

 

I dont see temps much below 180 unless the engine is cold. I do not pin the thermostat. With my cooler - towing 4000 lb trailer I will get to 200 on any grade - maybe 210 on a steeper longer hill. I still have to watch it and go slower up the hills but the temp will drop dramatically after I crest the hill. I got the bypass cooler since I live in MT. I wonder if pinning the thermostat open actually opens it up to a larger opening that when it opens conventionally? I can’t understand how these guys report temps in the 160s. Not with my truck. Hope this helps you. Gearcruncher might be helpful for you - try a pm

 

Thinking out loud, the aux cooler is downstream from the radiator cooling jacket.
Except in Sacramento or Phoenix it seems possible the temps can certainly go below 180 degrees, depending how generous the cooler is.

 

I think the issue is if you don't pin the tstat open then you're not circulating fluid through the coolers until the tstat opens at 187deg. And for me is honestly fine if the additional cooler helps keep temps from climbing when under load. I don't necessarily care if my temps are staying at 190 on the daily, I just want to keep temps from climbing too high while towing, specifically in the mountains.

I will see how it performs in a couple weeks when I head to Michigan. Theres a few good hills that should see temps try to rise. I figure I'll stay unpinned on the way out, and pinned on the way home and see how it compares.

 

Yes the thermostat doesn’t open until 187 degrees but it is upstream from the aux cooler which is not thermostatically controlled. The cooler will cool the oil depending on ambient air temp and air flow.

 

How is the cooler not thermostatically controlled? It's part of the circuit that the tstat opens and closes, is it not?

 

When the valve is not pinned open, it does not flow until 187 degrees as you note above.

When the valve is pinned open, or open at 187 degrees, then flow is full time.
The full flow of ATF temp is regulated in the heat exchanger tank built into the coolant radiator.

The aux tranny cooler is downstream of the heat exchanger tank, so it cools the ATF below the output temp of the radiator heat exchanger.

Depending on aux cooler size, type and any fans it may have, I can see where sub-180 degree temps are possible.
For my hot situation in Sacramento, I most certainly hope this is the case.

 

First off, thank you to all who have posted or shared their experience installing a transmission cooler here on TW. I've learned a ton.

For those who have later 3rd-gen trucks without the factory aftercooler, how are you routing the lines? I bought the @Iconic_ Hayden 698 kit (thanks, Devon!) and have the cooler mounted with the inlet and outlet pipes facing the passenger side of the truck just like the photos above. I'm trying to keep the factory routing through the radiator in place and am probably overthinking it. After a ton of searching, I've found a lot of pics from owners with the factory cooler, but I haven't stumbled onto any running only the Hayden 698 unit with no factory cooler.

Any recommendations? I'm still under warranty, so I'm wanting to keep the install as clean as possible (i.e., not take the radiator out of the loop).

 

I got mine installed and it looks great with the bracket. I got the bypass version (698) which I don’t think is needed. It seems like no transmission fluid gets sent to the transmission cooler until the thermostat opens. The cooler lines and the transmission cooler are cool to the touch unless I pin the thermostat open to make the fluid flow or wait till the thermostat opens at 187 degrees.

 

I ended up going non-bypass because I had the same thoughts. Not only does it not flow until the tstat opens, but tow package trucks with an OEM cooler have a warmer at the tstat housing that use coolant to heat the trans fluid. Should be no need for a bypass in the cooler.