Subaru WRX 4.44 LSD Package: TY754VB4AA 5-Speed with Matching Rear Diff

Ask any Subaru tuner about the best bang-for-the-buck drivetrain upgrade, and many will say the same thing: a 4.44 final drive with a limited-slip rear diff. This WRX 4.44 LSD package gives you exactly that. It combines a TY754VB4AA 5-speed AWD transmission with a matching 4.44 LSD rear differential for the 2002–2004 Impreza WRX. As a result, you get sharper acceleration and better traction in one bolt-in package.

What the 4.44 Ratio Does

Most US WRX models came with a 3.90 final drive. By comparison, a 4.44 ratio is shorter, so each gear pulls harder and the car feels noticeably quicker off the line and out of corners. In addition, the turbo spools sooner in each gear. However, the engine turns slightly higher RPM on the highway, which is a fair trade for most enthusiasts.

What the LSD Adds

An open rear differential sends power to the wheel with the least grip, so the inside wheel can spin when you accelerate out of a turn. A limited-slip diff, on the other hand, shares power between both rear wheels. Consequently, the car puts power down more cleanly on wet roads, in snow and on track.

Matched for AWD

On an all-wheel-drive Subaru, the front and rear ratios must match. Because the transmission and rear diff in this package are both 4.44, they’re already paired. If your car currently runs a 3.90, you must install both together. Also, expect the speedometer to read slightly differently after the change.

Fitment

• 2002–2004 Subaru Impreza WRX, 5-speed (bugeye and blobeye)
• 2005–2007 WRX: works with the correct clutch parts, so send us your VIN to confirm
• Not for the STI, which uses a 6-speed

For background, see the second-generation Subaru Impreza overview.

Swap Checklist

1. Install the transmission and rear diff together, so the 4.44 ratios match.
2. Fill both with fresh gear oil of the correct grade.
3. Fit the correct clutch kit, release bearing and fork, and resurface or replace the flywheel.
4. Inspect the mounts, axles and CV boots.

Professional Installation Available

Want it done right the first time? J-Spec Auto Sports installs the engines, transmissions and parts we sell at our shop in Henrico, Virginia, near Richmond. We install 4.44 LSD swaps on WRXs regularly, clutch service included. To get a quote or book a time, schedule an appointment or call 866-683-3747.

Shipping and Warranty

This WRX package includes a 30-day warranty. We drain the transmission and diff, cap them and strap them to a pallet, then ship by freight anywhere in the continental US. Local customers can also pick it up at our Henrico shop.

FAQ

Why upgrade to a 4.44?
It’s shorter than the US WRX’s usual 3.90, so the car accelerates harder in every gear.

Is the rear diff an LSD?
Yes. It’s a matching 4.44 limited-slip rear differential.

Do I have to install both parts?
Yes. The front and rear ratios must match on an AWD Subaru.

Will my speedometer change?
Yes, slightly, if you’re switching from a 3.90.

Will it fit my 2006 WRX?
It can, with the correct clutch parts. Send us your VIN to confirm.

Is there a warranty?
Yes, 30 days.

Can you install it?
Yes, at our Henrico, VA shop. Call 866-683-3747.