I have a 2010 auto, if I installed a large aftermarket trans cooler, would it be ok if I did not use the small factory cooler that is part of the AC condenser? On older stuff the factory trans cooler was in the radiator to pre-heat the trans fluid to operating temp.

 

The installation is much easier if you keep the OEM cooler in the circuit. There is no reason to completely bypass it.

 

I would just add the aftermarket cooler in addition to the stock cooler. I think that is what everyone else does, including myself when I had the 3.8. I did a Hemi swap and use the B&M cooler as the sole means of transmission cooling and use what would be the cooler in the radiator as a power steering cooler.

 

Just had a larger trans cooler installed and the shop wanted to make sure that when the small cooler was installed that the original cooling was still being used. Also, if running a supercharger be sure to install the trans cooler on the back side of the radiator to get air flow.

 

I just installed the PSC dual cooler for Trans and Power Steering. Every installation I have seen incorporates both coolers because what you are trying to do is increase the cooling capacity. If you add a cooler, while at the same time removing the OE cooler, you will probably be reducing the cooling capacity. Because the OE cooler is usually larger than the aftermarket cooler.

My Trans temp used to peak over 200 at times and with the new cooler, it peaks at 180. I have never seen it colder than 150, even in winter.

BTW, when you add a new cooler, make sure to plumb it into the cooling circuit from the transmission return hose. Also make sure you position the cooler so no air can be trapped in it. Never point the hose fittings on the radiator in the down position.

Good luck.

 

Not the case with the pre-2012 JKs. The OEM cooler is too small, and is not in the direct airflow through the grill.
But, like you said, it's best to keep the OEM cooler in the circuit, with the extra cooler in the return line so it's after the OEM cooler.

 

Thanks for the replies. Keeping the original cooler inline it is.