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Thumbnail Filmstrip of 1999-2007 7.3L / 6.0L Powerstroke Transmission Cooler Dieselsite COOLER6038 Images
The DieselSite COOLER6038 is a 40-row transmission cooler for a 7.3 and a 6.0. It replaces the factory cooler in the stack. DieselSite rates it past 90,000 GVW. The 1999–2003 factory cooler was rated about 28,000.
The core is a stacked plate, more rows than the common 37-row units. Fittings are the choice: 3/8-inch barbs for the 7.3 lines, 1/2-inch for the 6.0. Hoses are not in the master kit. A 1994–1997 OBS needs the bracket kit and line to clear an air-to-air intercooler. Pair it with the 4RCDK bypass delete on a 1999–2003 4R100, or the oil still skips the cooler.
It fits 1999–2003 7.3 trucks and 2003–2007 6.0 trucks.
Fitment
- 1999–2003 Ford 7.3L Powerstroke
- 2003–2007 Ford 6.0L Powerstroke
- 40-row stacked plate
- 3/8-inch or 1/2-inch fittings
- Rated past 90,000 GVW
- Hoses not included
An OBS truck needs the bracket option. The bypass tube on a 4R100 still has to come off, or this cooler only sees part of the flow.
The DieselSite COOLER6038 is a 40-row transmission cooler for a 7.3 and a 6.0. It replaces the factory cooler in the stack. DieselSite rates it past 90,000 GVW. The 1999–2003 factory cooler was rated about 28,000.
The core is a stacked plate, more rows than the common 37-row units. Fittings are the choice: 3/8-inch barbs for the 7.3 lines, 1/2-inch for the 6.0. Hoses are not in the master kit. A 1994–1997 OBS needs the bracket kit and line to clear an air-to-air intercooler. Pair it with the 4RCDK bypass delete on a 1999–2003 4R100, or the oil still skips the cooler.
It fits 1999–2003 7.3 trucks and 2003–2007 6.0 trucks.
Fitment
- 1999–2003 Ford 7.3L Powerstroke
- 2003–2007 Ford 6.0L Powerstroke
- 40-row stacked plate
- 3/8-inch or 1/2-inch fittings
- Rated past 90,000 GVW
- Hoses not included
An OBS truck needs the bracket option. The bypass tube on a 4R100 still has to come off, or this cooler only sees part of the flow.
Q
Samuel • 06/30/2026, 6:40:55 PM
Is this a direct bolt on application?
A
06/30/2026, 6:56:17 PM
Yes.
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5/5 Stars out of 2 Reviews
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INFRNL (CO) | May 25th, 2025
Replaced my 26 row 6.0 cooler on my 7.3. Easy direct bolt on upgrade. I don't think it's any better than my 26 row as far as performance but quality is a step above with JIC fittings. Wish it came with push loc fittings but supplied fittings are still great.
Also, fittings should have been 45-90* as 1/2" hose doesn't work the best with the straight fittings.
Not enough time yet, but temps are maintaining around 140*. I think the general rule is no more than 80* over ambient.
Size is probably around the same as an OEM 32 row 6.0 cooler. I'm glad it left room at the top for my 6.0 PS cooler.
Price is reasonable and overall I'm very happy with the purchase.
Also like the Dieselsite logo painted on it even though it's hidden by the condenser.
Bruce A Perkins (PINE KNOT) | August 14th, 2023
Worth every penny. Super easy to mount. Trans temp used to easily reach 175 and even over 200 in my utility truck. With this cooler; same truck, same weight, same roads, and hotter weather transmission temp hasn't gotten over 150.
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