Should I put an external trans cooler in my GX460?

[swild]

Just to throw my .02¢ in the mix.
I have a very heavy rig (R²M 2013 GX 460 Overland Build) that's been built since 2018m with about 128,000. I do not tow and I do not run a trans cooler. Albeit, I do monitor trans temperatures with my OBDLink in real time as I'm driving, especially when going up long steep grades.
I usually manual shift, when temps start to rise. Changed my trans fluids at 90k and scheduled to do it again at 140k.

What temps do you see when hitting those long steep grades?

 

[r2m]

What temps do you see when hitting those long steep grades?

Anywhere from around 190°'s F up to as high as 225° or 230° F. When it gets that high, I'm manually shifting, which just means I'm locking it in a lower gear at a higher RPM.
Remember, you have two temperatures, your trans AND your torque converter temps that are displayed.

 

[BC11SVT]

^ you should really consider an auxilary trans cooler.

 

[Rednexus]

^ you should really consider an auxilary trans cooler.

Agreed. I did this a couple weeks ago. 3,000-4,000 rpm wheelspin in foot-deep snow, going maybe 2 mph in actual ground speed, for 4-5 minutes. Got to the top of the hills and both my trans and engine were <200 F. In fact, my trans has never gotten above 200F with the CSF and Hayden cooler, even towing my 5,800# compact tractor up some very steep hills here, and dragging our camper up mountain passes in the West.

 

[BC11SVT]

Agreed. I did this a couple weeks ago. 3,000-4,000 rpm wheelspin in foot-deep snow, going maybe 2 mph in actual ground speed, for 4-5 minutes. Got to the top of the hills and both my trans and engine were <200 F. In fact, my trans has never gotten above 200F with the CSF and Hayden cooler, even towing my 5,800# compact tractor up some very steep hills here, and dragging our camper up mountain passes in the West.
View attachment 4081583

Getting a work out! I bet you would have seen 250+ with stock radiator and no cooler

 

[bryanle96]

Installing an external cooler is really not that much work since you're just tapping into the existing system. It's really a no brainier if you plan on keeping your truck long term.

 

[swild]

Yep, gonna do it. Sold

 

[Rednexus]

Getting a work out! I bet you would have seen 250+ with stock radiator and no cooler

I was most impressed pulling our camper west on Homestake Pass on I-90 in Montana. Several miles uphill in 3rd gear turning ~4,500 rpm, passing semis in the left lane. Engine maxed out at just a hair over 200F and the trans was cooler. Granted I have a manual lockup switch for the TCC that I was using, but other than burning a lot of fuel, the rig barely felt strained.

 

[Hiluxforever]

I would first suggest replacing the OEM radiator with a CSF aluminum radiator. That gets you a better radiator that should not crack/fail in the future, AND get you a better integrated trans cooler. I already had an external cooler when I upgraded to the CSF, but was still shocked at how much lower the radiator made trans temps (they stopped spiking when the torque converter unlocked). You can then watch your trans temps and decide if you also want an external cooler (or, just do both at the same time). If you are towing or wheeling at all (even if just a few times a year) I would suggest the CSF radiator AND an external cooler.

I had a Hayden 678 originally and upgraded to a 698. If their internal thermostat is working, I can't tell. It still over-cools in cold weather, and I have the cooler mostly blocked off now with a sheet of rubber. So I'd just get the 678. I have a GX470 that does not have it's own integrated trans thermostat.

This what I did. I just run a HD radistor and I dont tow or haul.

 

[thescreensavers]

Adding a trans cooler and a magnefine filter is the best longevity tools you can use on any automatic transmission. Not to mention one that has valvebody issues.

Lowering bulk temps = longer trans life it's that simple.