I have a small trailer I am towing with my 2005 G35x, and I was wondering how the trans cooler is stock. My trailer will weigh about 700-800lbs full and I wasn't sure if this would be too much for the stock cooler to handle or not on some hilly roads? I will probably use the manual shift mode to keep it in gear on inclines.

Oops, title was supposed to read, "with towing." Haha.

 

I think it depends on how much you are going to do this. If it is a one time thing I wouldn't worrry about it. If it is going to be regular thing I would think about an auxiliary cooler.

 

Only when I move. And possibly when I bring my snowmobile home for winter break, but that's only going to be about 600lbs total weight. So maybe 5-8 times per year. 400 mile drives. The last or first (depending whether I am going to or from school) 75 miles can be sort of hilly, but otherwise it's just Wisconsin farmland.

 

If you get a cooler, it needs a thermostat.

Snowmobile? Just adding a cooler with no thermostat in that climate could cool too much. Too cool means water in the fluid not flashing off. The fluid gets compromised. The opposite situation with no cooler is too high of temps.

If I were you, either get a cooler with an inline thermostat or decrease your service intervals (30k to 15k or something similar)

 

^ There is no water in ATF, if any water gets in the ATF you are in big trouble. Automatics do not like water at all, this is why if you get coolant in the ATF( Looks like strawberry milkshake) your trans is SOL.

The OEM transmission has a build in thermostat for the cooler which opens at 100F +/- 20F. The OEM cooler really functions as a oil warmer at start up and is for light duty. You can install a B&M cooler like I did HERE which contains an fluid bypass. So it shouldn't overcool.

The Temperature coming out of the OEM cooler(if its able to fully dissipate the heat from the trans) should be around +/- 20F from coolant temp. Which means It should be ~170+

Installing a cooler afterward will give you the best cooling. But if you want to have a safety net and to have it as close to OEM temperature install the cooler before the OEM cooler.


It should also be said, check the door sill, it will show you the cars fully loaded weight limit. This is what the car should be able to handle. If you are under that. Just you and what you are towing you should be ok, but it cant hurt to install a cooler at all. Personally I would recommend any enthusiast to install one.

 

Thanks guys. First trip went great for the car (other than the wheel that fell off my trailer). I might still look into a cooler though since it's cheap and easy. Does my car have an external cooler stock or is it just built into the radiator?

 

^ Its just built into the radiator