DSS 2003-2004 Ford Mustang Cobra w/ T56 Magnum Trans 950HP Aluminum Driveshaft FDSH8-MAG-F
Swapping a 2003-2004 Mustang Cobra to a Tremec T56 Magnum is one of the most popular upgrades for a Terminator making big boost, and it leaves you needing a driveshaft built for the new gearbox. This is the Driveshaft Shop one-piece aluminum driveshaft for the 2003-2004 Cobra with a T56 Magnum, maker part FDSH8-MAG-F (SKU 610100). It is new and sold as a 950 horsepower shaft, and it is the piece that gets a Magnum-swapped Cobra back on the road without a custom-built tube.
The factory Cobra shaft and the factory-T56 replacement are built around the original transmission. Driveshaft Shop makes a separate part for the Magnum, and the difference is on the front end: FDSH8-MAG-F uses a billet transmission yoke made for the Magnum output, where the factory-T56 version does not. On the rear, it uses a Sonnax forged aluminum 1350-series flange that bolts to the Cobra's independent rear differential. The tube is 3-1/2 inch aluminum with solid U-joints at both ends, and the assembly is high-speed balanced before it ships. In service, this shaft takes every bit of torque the Magnum puts out of its tailshaft and carries it back to the IRS, which is exactly where a stock part runs out of margin on a high-power Cobra.
Many post-swap vibrations come from the install, not the parts. Confirm the transmission crossmember and mount are correct for the Magnum and that the transmission sits at the right angle; Driveshaft Shop notes that angle-related vibration usually appears around 30-45 mph, while a shake under 15 mph points to something bent or out of balance. Measure how far the yoke slides onto the output with the car at ride height, and see our driveshaft length measurement guide for how to do it. If the noise changes with the gear selected instead of with speed, the issue is inside the gearbox, and our T56 Magnum rebuild cost guide is the place to start. For more on what manual gearbox repairs run, read automatic vs manual transmission repair cost.
FDSH8-MAG-F is listed for 2003-2004 Ford Mustang SVT Cobra cars converted to a Tremec T56 Magnum. If your Cobra still has the factory T56, you want the FDSH8-AF factory-T56 shaft instead. Magnum swaps are not all built the same way, so match your crossmember, mount and transmission version, and send us your year, VIN and swap details if you want a second set of eyes before ordering. For a 2015-up Mustang GT with a Magnum XL, the correct part is the 2015-up GT Magnum XL aluminum shaft.
Building the gearbox side too? A billet reverse lockout solenoid delete is a common add-on for Magnum swaps where the car's wiring does not run the factory lockout solenoid.
| Brand | Driveshaft Shop |
| Part number | 610100 |
| Fits | DSS 2003-2004 Ford Mustang Cobra w/ T56 Magnum Trans 950HP Aluminum Driveshaft FDSH8-MAG-F |
| Vehicle fitment | Ford Mustang Cobra (2003-2004) |
| Type | Driveshafts |
| Condition | New |
| Ships | Same business day (in stock), from the USA |
| Warranty | 1-year |
Doing this repair right usually means replacing these at the same time. Same transmission, ships together.
FDSH8-MAG-F is built for a Cobra converted to a T56 Magnum and uses a billet transmission yoke made for the Magnum plus a Sonnax forged aluminum 1350 rear flange. FDSH8-AF is for the factory T56.
No. A Cobra with the original T56 should use FDSH8-AF. This part is made for the Magnum swap.
The rear uses a 1350-series forged aluminum flange designed to bolt to the 2003-2004 Cobra differential flange.
Check the transmission mount and crossmember, operating angles and yoke engagement first. Driveshaft Shop notes 30-45 mph vibrations usually come from angles, and shakes under 15 mph point to a bent or unbalanced part.
Use the fluid Tremec specifies for the Magnum and fill to the bottom of the fill plug. Do not reuse whatever was in the old factory T56.
