Tru-Cool Max 40k Transmission Cooler

[Matthew Jeschke]

Got a thermal bypass installed. Little video below...

New video by Matthew Jeschke

photos.app.goo.gl

 

[Matthew Jeschke]

Dumb question - because someone already probably covered it..... Assuming the "cooler" inside the radiator is still in play, which side would you cut into to attach an additional cooler? I like the idea that when it is cold the radiator might quickly heat the trans fluid to what it needs to be.
A thermostat I like is this one that comes with 6AN fittings and can be ordered with different thermostat settings. A bit pricey ($159) but in the grand scheme of things not so much.

View attachment 424997

Cut into the side coming out of the radiator (liquid to liquid cooler) to the liquid to air cooler. You want to have the liquid to liquid cooler help heat up the trans to operating temperature.

It's pretty simple... splice the thermostat into the lines going to the front, liquid to air cooler. Return to transmission is the driver side hose on the cooler... the input (hot line from liquid to liquid cooler) is the passenger side into the liquid to air cooler.

Hopefully that makes since.

TIP: I recommend cutting the return line (driver side). Cut it back where the rubber ends on return to transmission. So your going to remove the entire line including rubber piece up to the trans cooler. That was a PITA to deal with that side. Then get an AN6 fitting and install rubber line to the metal hose running from the transmission. I used aluminum hose to plumb all mine up... just wish I'd had some AN6 for that little run. Feel free to PM me with any questions.

The HOT side from radiator was fairly simple to work with otherwise.

I just finished this project minutes ago.

...

That bypass in your picture was too spendy for me to warrant buying. Derale makes one, I just bought it. Seems to work, at least for first mile of driving haha... I finished installing it minutes ago.

Only big difference is it doesn't come with the fittings like that you have to buy them / adapt it to what you want to hook it to. It also appears to be a cast part body that one is machined from billet, would be super expensive to make, probably why it cost so much.

Derale has a always flow / cannot plug design feature that makes it a bit more attractive too. Not sure if that one is that way or not...

 

[2006Tahoe2WD]

Yes I follow. Do you have a temperature gauge(s) to see how the bypass modulates?
Thanks.

 

[Matthew Jeschke]

I have the cluster with the temp gauge. I'd highly recommend swapping out if you don't have one. That said, under normal duty, these transmissions are really hard to overheat w/ the factory setup.

I venture the bypass I installed won't activate until this summer when I'm out using 4wd climbing rugged slopes in over 100F temps.

I can tell though in the few minutes I tested the bypass after install that it's warming the transmission up nicely, while keeping the cooler pressurized. Prior to contrary belief a warm transmission is a happy one (150F to 200F is my target temp range)... It's the scorching hot transmission you want to avoid.

In hindsight, one of the BEST mods you can do is your coolant fans. If you have electric turn them on at a bit lower temperature... I have mechanical so I installed a heavy duty fan clutch.

 

[2006Tahoe2WD]

I'm not sure what I will do. Right now at 181k miles I baby the transmission in hopes of keeping it alive. No towing or real hot weather. Last year I drove over Sonora Pass on July 3 but it was cool because of the altitude.
At one point I looked at changing the dash and getting the odo set properly but they can't set all the numbers e.g. fuel used, hours/etc. There might be a way to add the trans. temp. I could setup my cell phone and blue tooth to watch the temp and see what happens via OBD II.

 

[Matthew Jeschke]

If you're only doing normal driving (no towing), even if you are doing light towing... There's little chance you're overheating. Your name leads me to believe you have a 2006? In which case you'd have electric fans. Likely you don't even need to fiddle with those but can lower temp they turn on if you have means, I'd probably go to 180F t-stat as well if you do that. I'm not sure if 2wd came with the liquid to air cooler (in front of the radiator). If not you could add one if you're concerned, if it's factory cooler you may not need the thermal bypass. Strong possibility factory be plug and play as well.

As far as keeping your transmission alive. Clutches & seals so long as they live in good fluid and aren't over heated, like over 225F... Then they should be fine. Somebody may correct me here, I've only fiddled with a few vehicles in my own garage. My trans had ~ 240k miles on it. Worked like a champ, I only swapped cause I wanted to.

GM worked out most of the glitches in the 4L60E by 2006. I believe factory started to put in a hardened (heat treated) sun shell along with corvette servo (or similar) on all the 4L60E builds after 2000ish, a 2006 would certainly be included in that. Only thing, I'd recommend is a boost valve for the pump, plastic check balls, and pin-less accumulators. The plastic accumulators from the factory SUCK. All this can be done when you service your transmission from the service pan.