Tru-Cool Max 40k Transmission Cooler

[Matthew Jeschke]

I'm having a horrible time with this dumb cooler. The cooler I shouldn't pick on as much as the thermostat. It's got me ready to rip it off and throw it in the garbage. My trans runs SUPER cold. WAY too cold. I bought the thermostat which came with no fittings, and no instructions. Everybody on internet is installing JUST the cooler so I cannot make much headway.

Here's my problem...

Thermostat has what looks like a 3/8" push connect fitting but isn't. There's no lip on it to go with the sealing oring in a push connect nut. See image...



Next I have to find a MESS of fittings to go from a 5/8-18 male hose nut, to a 5/8-18 male quick connect even if I could figure that out... I don't think it'll work with a quick connect...

What on earth is that garbage fitting they have on the thermostat there? How do you best interface with it short of a rubber hose and hose clamp?

I'm almost ready to throw this thermostat in the garbage. I saw one tutorial, the only one where a guy used a thermostat. He used this one but it's $200

High-Flow Engine & Transmission Oil Cooler Thermostat

Improved Racing's Flow Series Motor Sport (FSM) oil thermostat is a universal solution that can be used with any oil cooler on any vehicle or industrial application flowing up to 20 GPM (75.71 LPM). Trusted by professional race teams, OEM's, and military contractors. Accelerates fluid warmup...

www.improvedracing.com

Has fittings that make since. Oh and I cannot seem to get any tech support from tru-cool. Has anybody ever reached out to them before?

 

[Mudsport96]

Sorry man wish I could help, but I have not used one of these before.

 

[gooffeyguy]

Is your trans still plumbed through the radiator, then to the Tru-cool?

The fittings on that thermostat look like just a barb fitting used with rubber hose and a clamp. Don't use a worm gear clamp, it'll leak in winter. Use a spring clamp.

 

[Matthew Jeschke]

Is your trans still plumbed through the radiator, then to the Tru-cool?

The fittings on that thermostat look like just a barb fitting used with rubber hose and a clamp. Don't use a worm gear clamp, it'll leak in winter. Use a spring clamp.

Yeah I kept the radiator cooler connected. Somebody told me and I didn't know any better, that I'd not need the thermostat because I'm going through the radiator cooler.

I'm throwing that tru-cool thermostat away. Cooler is getting to be a bit of a money pit That said, guy who sold it to me just gave me my money back. Was a bit shocked. I bet it came in a kit and he didn't want to use it either.

Called summit racing Derale makes an oil thermostat that is MUCH better than that tru-cool one. It is also the same price It uses threaded fittings to connect line set. $120 for all the fittings, line, & parts.

Derale Cooling Products 25791 Derale Fluid Control Thermostats | Summit Racing

Free Shipping - Derale Fluid Control Thermostats with qualifying orders of $109. Shop Remote Oil Thermostats at Summit Racing.

www.summitracing.com

I bought 25' of aluminum hose so I can also do away with the line couplers and have a solid piece of line. I could have used AN hose but I like the metal line better.

Then he sold me fittings to put on the thermostat so I don't have to use a flare tool for the thermostat side... I think with that nice bracket included in kit I can mount the thermal bypass on the underside of the core support behind where the clip was originally for the line set OR right where the line set clip on the core support is. Then bend new lines from the thermostat to the cooler.

Should turn out pretty slick. What might be even better but I couldn't find a solution for the 4L60E is the thermal bypass they put on newer 6 speed automatic transmissions. Those clip right into side of trans case then line set goes out from them. Unfortunately, I couldn't find one for a 4L60E. And unsure if dimensions are same to fit a 4L60E. That would be SUPER slick, factory solution. Then they sell kits to make them more robust. I guess the factory can tend to fail from time to time so there's a few aftermarket rebuild kits to address the factory issue.

I think this is one thing I definitely need to do a video tutorial on trans temperature & thermostats when I get time. I spent forever scrolling YouTube trying to get best ideas for installing the thermal bypass. Seems everybody is on mantra throw the thermostat away, as cooler is better. Only two guys talked about thermostats. Everybody else just says colder the fluid the better.

 

[SnowDrifter]

Out of curiosity, what's your plumbing order for the cooler + radiator pass through, and what sort of temps are you seeing? Mine settles in around 100f on cold days, order is cooler, then radiator, then back to transmission

 

[Matthew Jeschke]

Great question, I couldn't say, I need to trace the lines. I had really thought it was trans, radiator, cooler, then back to trans but honestly, I've never traced it.

My temps are 100F to 120F. Ambient ranging from 45F to 75F. I think in summer when it's 115F cooler would be fine more or less. If it rains, then of course cooling efficiency is much better and I get down under 100F.

Couldn't help but notice.. in your signature "Original 4L60e god help me"... It should hold out fine, so long as you don't have a check ball pass through the separator plate. I'd swap those with the Sonnax plastic ones next time you drop the service pan. You can throw a boost valve in the pump at the same time and pin less accumulators. I think GM fixed addressed failure points in case such as a hardened sun shell by then.

 

[SnowDrifter]

Right on

Honestly I'm not sweating about those temps. Sig needs to be updated. I'm just shy of 185k with the original trans.

Just kind of a cheeky jab since I've seen them go out around this time. Actually iirc don't they like to conk around 160ish?

 

[Matthew Jeschke]

Ah gotchya, I was running my original 4L60E up to 240k miles, when I swapped with another I built up. Never had any issues with it.

What temps you see with your Tru Cool cooler?

Did you notice a loss in MPG?

I'm also troubleshooting a 2MPG loss around the time I put the cooler on. Not sure if it's that, or something else.

 

[2006Tahoe2WD]

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.

 

[2006Tahoe2WD]

Most routing info. I see has the hot fluid from the trans. going to the water radiator first - like this.