Universal 3/8" Hose | Part Number: #678
The Davies Craig Hydra-Cool® 23 Plate Transmission Oil Cooler is a premium cooling solution engineered to keep automatic transmission fluid (ATF) at its optimum operating temperature. Featuring advanced plate & fin technology, the Hydra-Cool® design delivers superior heat transfer while requiring up to 33% less mounting space than a comparable tube & fin cooler, making it ideal for modern engine bays where space is at a premium. High-efficiency internal turbulators maximise heat dissipation while maintaining low pressure drop for outstanding cooling performance.
Designed for performance vehicles, 4WDs, towing, commercial fleets and motorsport applications, the Hydra-Cool® 23 Plate Oil Cooler effectively reduces transmission temperatures to protect against premature wear and costly repairs. Manufactured from lightweight aluminium and 100% pressure tested to 150 psi, every Hydra-Cool® Oil Cooler is built for long-lasting durability and reliability.
Recommended for:
| Specification | Details |
|---|---|
| Part Number | 678 |
| Cooler Type | Hydra-Cool® Plate & Fin |
| Number of Plates | 23 |
| Construction | Aluminium |
| Overall Dimensions | 281 × 229 × 20 mm |
| Core Dimensions | 281 × 200 mm |
| Hose Size | 3/8" (9.5 mm) |
| Heat Transfer Capacity | 13,937 BTU/hr |
| Fluid Capacity | 76.7 ml |
| Pressure Tested | 150 psi |
Heat is one of the leading causes of automatic transmission failure. Heavy towing, stop-start traffic, steep climbs, off-road driving and high-performance applications all increase transmission fluid temperatures, reducing lubrication and accelerating wear on internal transmission components.
The Davies Craig Hydra-Cool® 23 Plate Transmission Oil Cooler removes excess heat before the fluid returns to the transmission, helping maintain optimum operating temperatures, improve shift quality and extend transmission life. Its premium plate & fin construction delivers exceptional cooling efficiency in a compact package, making it the ideal solution for vehicles requiring maximum cooling performance.
All Davies Craig transmission oil coolers are universal fit, making it easy to choose the right cooler based on the available mounting space rather than your vehicle's make or model.
Use the Transmission & Engine Oil Cooler Product Selection Guide (below) to identify the recommended transmission oil cooler for your application. The guide considers factors such as:
This will recommend the appropriate transmission oil cooler size for your application.
Some applications benefit from the addition of a Thermatic® Electric Fan to provide consistent airflow through the oil cooler when natural airflow is limited.
A fan is recommended for applications including:
The Transmission & Engine Oil Cooler Product Selection Guide will indicate when a Thermatic® Fan is recommended for your application.
Most transmission oil coolers are mounted in front of the radiator or air conditioning condenser to maximise airflow.
Measure the available installation area and record the following dimensions:
As a general rule, the largest transmission oil cooler that comfortably fits within the available space will provide the best cooling performance. A larger cooler offers greater heat dissipation, helping to maintain lower automatic transmission fluid (ATF) temperatures, particularly when towing, carrying heavy loads, driving off-road, or operating in hot conditions.
Once you have your dimensions, visit the Davies Craig Transmission Oil Coolers page and review the Specifications & Range table located approximately halfway down the page.
There you can:
If you're unsure which transmission oil cooler is best suited to your vehicle, our technical team is here to help.
Simply take your measurements and contact Davies Craig—we'll be happy to recommend the most suitable oil cooler for your application.
|
PRODUCT SELECTION GUIDE Transmission & Engine Oil Coolers |
||||
|---|---|---|---|---|
|
Vehicle Type |
APPLICATION |
|||
| Standard Duty / No Towing | Medium Duty/Light Towing | Heavy Duty/Heavy Towing | Super heavy Duty Transmission cooler or Engine oil cooler | |
|
Part Number |
Part Number |
Part Number |
Part Number |
|
| 4 Cyl. Up to 1990* |
#401 or #676 |
#403 or #676 |
#404 or #677 |
#602 |
| 6 Cyl. Up to 1990* |
#403 or #676 |
#404 or #677 |
#678 or #679 |
#602 |
| 8 Cyl. Up to 1990* |
#404 or #677 |
#678 | #679 |
#602 or #605 |
| Small Car | #676 | #677 | #678 |
#602 or #605 |
| Sedan / Wagon | #677 | #678 | #679 |
#602 or #605 or #610 |
| 4WDs & SUV | #678 | #679 | #602 |
#605 or #610 |
| Commercial | #678 | #679 |
#602 or #605 |
#610 |
| Cooler and Fan combo recommended for low-speed driving/towing and off-road applications | ||||
| Small Car |
#698 (12V) #699 (24V) |
#698 (12V) #699 (24V) |
#698 (12V) #699 (24V) |
#600 (12V) or #614 (12V) or #608 (12V) |
| Sedan / Wagon |
#698 (12V) #699 (24V) |
#698 (12V) #699 (24V) |
#691 (12V) #692 (24V) |
#600 (12V) or #614 (12V) or #608 (12V) |
| 4WDs & SUV |
#698 (12V) #699 (24V) |
#691 (12V) #692 (24V) |
#600 (12V) #692 (24V) |
#600 (12V) or #614 (12V) or #608 (12V) |
| Commercial |
#698 (12V) #699 (24V) |
#691 (12V) #692 (24V) |
#600 (12V) #692 (24V) |
#608 (12V) |
| Oil Cooler Accessories recommended for specific Transmissions | ||||
| GM-Holden Transmission | Select cooler as above plus #1005 | Select cooler as above plus #1005 | Select cooler as above plus #1005 | Select cooler as above plus #1005 |
| 6R80 Transmission | Select cooler as above plus #1006 | Select cooler as above plus #1006 | Select cooler as above plus #1006 | Select Part # as above plus #1006 |
| Power Steering Oil Cooler | ||||
| Vehicle | Standard Duty | Medium Duty | Heavy Duty | Super heavy Duty |
| All Vehicles | #1009 | #401 | #403 | #404 |
|
SPECIFICATION & RANGE Transmission & Engine Oil Coolers |
|||||||||||
| Part # | Image | Plates | Thickness mm |
Overall | Core | Inlet/Outlet Size |
Hose Size | Heat Transfer Rate (BTU/HR) |
Fluid Capacity |
||
| Width mm | Height mm | Width mm | Height mm | ||||||||
|
Power Steering Cooler & Ultra-Cool Transmission Oil Cooler (Tube & Fin) |
|||||||||||
| 1009 |  |
Tube & Fin |
19 | 237 | 64 | 148 | 64 | 3/8” 9.5mm |
3/8” (9.5mm) 1.2m |
4,000 | 43ml |
| 401 |  |
20 | 326 | 128 | 245 | 128 | 9,000 | 122ml | |||
| 403 |  |
20 | 326 | 191 | 246 | 191 | 10,800 | 207ml | |||
| 404 |  |
20 | 395 | 191 | 316 | 191 | 12,000 | 248ml | |||
| Hydra-Cool Transmission Oil Cooler (Plate & Fin) | |||||||||||
| 676 |  |
12 | 20 | 281 | 141 | 281 | 112 | 3/8” 9.5mm |
3/8” (9.5mm) 1.4m |
11,987 | 81ml |
| 677 |  |
17 | 20 | 281 | 180 | 281 | 152 | 13,394 | 115ml | ||
| 678 |  |
23 | 20 | 281 | 229 | 281 | 200 | 13,937 | 158ml | ||
| 679 |  |
30 | 20 | 281 | 300 | 281 | 265 | 15,710 | 201ml | ||
| Transmission Oil Cooler & Fan Combo Kits | |||||||||||
| 698 (12V) |
|
23 | 76 | 281 | 229 | 281 | 200 | 3/8” 9.5mm |
3/8” (9.5mm) 1.4m |
13,937 | 158ml |
| 699 (24V) | |||||||||||
| 691 (12V) | 30 | 76 | 281 | 300 | 281 | 265 | 15,710 | 201ml | |||
| 692 (24V) | |||||||||||
| Universal Engine/Transmission Oil Cooler | |||||||||||
| 602 |  |
14 | 32 | 258 | 224.5 | 258 | 185.5 | AN10 ORB | N/A | 21,000 | 500ml |
| 605 |  |
19 | 50 | 330 | 166 | 285 | 142 | 37,000 | 440ml | ||
| 610 |  |
30 | 50 | 330 | 249 | 285 | 226 | 50,000 | 690ml | ||
| 616 |  |
14 | 32 | 258 | 224.5 | 258 | 185.5 | M16 | N/A | 21,000 | 500ml |
| Universal Engine/Transmission Oil Cooler & Fan Combo Kits | |||||||||||
| 600 (12V) |  |
14 | 87 | 258 | 224.5 | 258 | 185.5 | AN10 ORB | N/A | 21,000 | 500ml |
| 608 (12V) |  |
30 | 106 | 330 | 249 | 285 | 226 | 50,000 | 690ml | ||
| 614 (12V) |  |
14 | 87 | 258 | 224.5 | 258 | 185.5 | M16 | N/A | 21,000 | 500ml |
| Accessories | |||||||||||
| 1005 |  |
5/16" (8mm) Adaptor Kit - Transmission Oil Cooler to suit GM transmissions | |||||||||
| 1006 |  |
Transmission Oil Cooler Fitting Kit (6R80) Suits Ford Ranger and Mazda BT50 | |||||||||
| 1007 |  |
Transmission Temperature Sensor Adapter Kit - suits 3/8” Hose and 1/4” NPT Sensor | |||||||||
| 1008 |  |
AN10 ORB to 3/8" Push on Hose Barb Fitting | |||||||||
| 1010 |  |
Transmission Oil Cooler Fitting Kit (AN10 ORB to 3/8" Hose) | |||||||||
| 579 |  |
Quick Fit Kits (Mounting Kit) | |||||||||
| 0444 0445 0500 |
 |
Digital Thermatic® / Electric Fan Switches | |||||||||
Please visit our buy online section to view the Davies Craig TRANMISSION OIL COOLER range.
