CSF 20009 OEM Style Replacement Transmission Oil Cooler (2003-2007 5.9L Cummins)

Fitment

Fits 2003-2007 Dodge Ram 2500 and 3500 pickups with the 5.9L common-rail Cummins. The title, CSF's application (Ram 2500/3500 pickups) and our catalog tags agree on these years. The 2007 model year was built with both the 5.9L and the 6.7L; this cooler is listed for the 5.9L only, so a 2007.5 truck with the 6.7L is not covered.

The 20009 replaces the factory transmission oil cooler. Early 2003 standard-output trucks may have a 47RE automatic instead of the 48RE, and CSF does not split this listing by transmission, so send us your VIN if you have an early 2003. If your truck has a manual transmission, call us before you order. When in doubt, verify fitment by VIN or call the shop.

Why this part

High temperature is the single most damaging factor for powertrain life. As the coolers in front of the engine age and clog with debris, they lose capacity, and transmission and intercooler temperatures climb, especially under tow. The 48RE automatic behind the common-rail Cummins can fail in the 100-150k-mile range even at factory power, so keeping its fluid cool is part of making it last.

The 20009 is a parallel-flow cooler with a 23 x 13 in core, 5/8 in thick, with tube-style inlet and outlet connections. It bolts in where the factory cooler was, so there are no brackets to fabricate. Pair a healthy cooler with the 48RE's 30k fluid, filter and band service; on an unbuilt truck that schedule is the cheapest insurance you can buy.

What you get

• One CSF 20009 transmission oil cooler, parallel-flow construction
• Tube-style inlet and outlet
• No lines or mounting hardware are listed as included

Specifications

Features:

• Direct-Fit Replacement

Specifications:

• Construction: Parallel Flow
• Core Length (in): 23
• Core Thickness (in): 5/8
• Core Width (in): 13
• Hazardous Material: No
• Inlet Tube: Tube
• Outlet Tube: Tube

Applications:

• For use on Ram 2500/3500 Pickups

Installation notes

The 20009 is a direct-fit replacement made to bolt in place of your factory transmission oil cooler. Have a pan ready to catch fluid when you disconnect the old cooler, then check the transmission fluid level and top off with the correct fluid once the new one is in. If you are replacing the cooler after a transmission failure, flush the cooler lines first so old debris does not go into the new core.

About CSF

CSF is a family-owned cooling manufacturer in Rancho Cucamonga, California, building parts since 1947. Next to its radiators, intercoolers and A/C condensers, it makes OEM-style replacement transmission oil coolers for 5.9L Cummins Rams. Every CSF design is tested in-house for burst pressure, vibration, thermal cycle and salt spray corrosion.

Frequently asked questions

Is this an auxiliary cooler or a factory replacement?

It is a factory replacement that bolts in place of the stock transmission oil cooler. If you tow heavy and want more cooling than stock, a heavy-duty auxiliary cooler and a deep transmission pan are common 48RE upgrades. Ask us and we will spec them for your truck.

How do I know my transmission is running too hot?

On these trucks, 48RE fluid temperatures over 260 F while towing in overdrive trigger protective downshifts. If the truck hunts or forces a downshift on grades, or the fluid looks dark, check the cooler and the fluid before it turns into a bigger repair.

Will it fit a 2007.5 Ram with the 6.7L?

No. The 20009 is listed for 2003-2007 trucks with the 5.9L Cummins. The 6.7L trucks that arrived for 2007.5 are a different application, so call us with your VIN for the right part.

Questions on fitment? Call the shop at the number in the header. We install everything we sell.