What Size Fittings Are the Transmission Fluid Lines In The Radiator On a 2003 Chevrolet Silverado

Question:

What type of threads are on a transmission cooler ?i want to bypass the cooler and plug it off at the lines

asked by: Rob

Expert Reply:

Are you referring to the fittings on your factory transmission cooler in the radiator or are you referring to the Derale Insta-Dapt Radiator Adapter included with the Derale Dyno-Cool Tube-Fin Transmission Cooler Kit part # D12904? If you are referring to the fittings on your factory transmission cooler in the radiator then they are 5/8". If you are referring to the Derale Insta-Dapt Radiator Adapter then this is a 1/2".

Please keep in mind that that the factory transmission cooler in the radiator will provide more cooling power than a standard transmission cooler will. Therefore, if you will be bypassing the factory transmission cooler in the radiator you will want to upgrade to a remote mount cooler such as the Derale 16-Pass Electra-Cool Remote Cooler Assembly w/ Fan part # D13700.

The Derale Dyno-Cool Tube-Fin Transmission Cooler Kit part # D12904 that you referenced would not provide nearly enough cooling power for your vehicle's transmission if you were to bypass the factory transmission cooler in the radiator. However, if you chose to do so anyhow then you can attach the two transmission lines using the Derale Radiator Adapter Fittings part # D13028.

If you wanted to use this cooler then I recommend just installing in front of the radiator after the fluid has already gone through the radiator as this would allow for sufficient cooling power. If this is the route you were to take then you would also need to use the Derale Radiator Adapter Fittings for GM part # D13018.

If the above is not what you were asking then please just let me know and I will be happy to see if I have other information for you.