I was wondering if anyone with a trans. cooler bypassed the stock cooler in the radiator and just used the aftermarket cooler. Is there any reason they say to run both in series.

 

I wldnt recommend that . I hve one and didnt bypass I still used the radiator and made it go thrgh the radiator first then to the trans cooler to get cooler before returning to the transmission. that way you he cooler fluid going to the transmission.

 

Route fluid thru aftermarket cooler first, then thru the stock, in-radiator cooler.

Some aftermarket coolers can cool the fluid more than is desired, reducing tranny life. Remember, cool fluid is better than hot fluid, UP TO A POINT. Beyond that, continued reduction of fluid temp is actually detrimental.

In addition, running tranny fluid thru the aftermarket cooler first can take some heat load off the engine cooling system. And this routing provides more consistent tranny fluid temps because the engine coolant temp is more consistently maintained via the thermostat.

Kirk