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Inside The Banks Billet Torque Converter


Jun 16, 2017
Photographers: Jason Gonderman
For most people, knowing exactly how a torque converter works is a mystery. It’s completely understandable, as the modern torque converter is a complex device. In short, a torque converter is an rpm-controlled fluid coupler, linking the engine and transmission. The torque converter installed behind your modern diesel engine is entirely adequate for all the tasks the pickup rolled off the assembly line is destined to perform. The trouble, however, comes when it’s tasked with handling increased engine power, heavy payloads, or large trailers.
The fact is, most transmission failures in mildly modified diesel trucks can be linked to the torque converter. Additional power made by the addition of a tuner can exceed the handling limits of the factory converter’s clutches, resulting in slippage, and ultimately heat. This heat, and the debris created from the accelerated wear of the converter clutches, quickly pollutes and damages the rest of the transmission. After all, heat and contamination are the top killers of automatic transmissions.
Photo 2/7   |   Banks Billet Torque Converter
From Left to Right:
1 – Billet Steel Front Cover
2 – Clutch Assembly
3 – Additional Clutch Friction Plate
4 – Improved Clutch Pressure Plate
5 – Turbine With Welded Hub
6 – Stator With One-Way Roller Sprag
7 – Impeller Housing
In addition to the destruction of the converter’s clutches, it can also suffer damage to the stamped metal fins of the impeller and turbine. In extreme cases, the stamped-steel front cover can become distorted. This is where the Banks Billet Torque Converter comes in. By correcting some of the most common failure points inside the torque converter, transmission life can be greatly extended.
The Banks torque converter starts out by using a machined forged billet steel front housing. This billet housing provides improved support for the internal lockup clutch, allowing it to remain completely flat under all conditions, resulting in improved lockup performance and less slippage. The lockup clutch has been upgraded to increase engagement. Improvements over the factory converter also include a welded turbine hub, a stator that’s supported by Torrington bearings, and furnace-brazed stator fins aimed to prevent loosening over time. The fin angles of the stator have also been optimized for increased efficiency. The entire assembly is blueprinted for precision control of tolerances and balanced for smooth rotation.
Photo 3/7   |   The Banks Billet Torque Converter is designed with a nonslip, three-friction-element clutch system that is rated to hold three times the torque of the factory Allison converter. This converter is able to hold 1,800 lb-ft of torque and is said to cut nearly a second off of 0-60 times thanks to its optimized internal design.
Replacing the factory torque converter with an upgraded unit like the Banks billet converter is the most practical way to prevent damage when adding power or hauling heavy and should be thought of early—before transmission damage is allowed to occur. Dollar for dollar, an upgraded torque converter is one of the best modifications for your performance diesel.
Photo 4/7   |   The billet converter gets its name thanks to the machined forged billet steel front cover. This solid foundation provides a precision mating surface to the engine’s flexplate and ensures the lockup clutch remains uncompromised, even under the most severe demands.
Photo 5/7   |   Prior to installation, we filled the converter with 1 quart of Amsoil automatic transmission fluid, per the instructions. Doing this prevents damage that can occur from running dry on the initial startup. We chose Amsoil’s Signature Series ATF due to its increased ability to protect against extreme heat from heavy towing, hauling, and increased engine power—all things we plan to do with this Chevrolet 2500HD truck.
Photo 6/7   |   We had a very difficult time finding the correct bolts for attaching the Allison torque converter to the Duramax flexplate. Sure, we could use the factory bolts, but we were looking for improved performance. Turns out ARP’s part number 230-7305 (converter bolts listed for GM’s 4L60 and 4L80 transmissions) are the exact size needed for the Allison. You’re welcome.
Photo 7/7   |   Installation of the converter is pretty straightforward. Whether you do it with the engine out of the truck and transmission in it, like we did, or vice versa, the process is the same. Carefully lift the converter into place, sliding the drive hub onto the input shaft. It’s important to measure the depth of the original converter before removal so you can be certain the new one is fully seated.

Parts List

Amsoil Signature Automatic Transmission Fluid
MSRP $13.75/quart
ARP Torque Converter Bolts
Part #230-7305
MSRP $28.64
Banks Billet Torque Converter
Part #72510
Applications: ’01-to-’10 Duramax
MSRP $1,499.00


ARP (Automotive Racing Products)
Ventura , CA 93003
Gale Banks Engineering
Azusa, CA 91702
Superior, WI 54880