November 5, 2023 Cornelius Tan

How to Manual Swap a Lexus GS300 Using a W58 Transmission

I picked up this GS300 with a clear goal in mind: swap in the spare W58 transmission I had sitting in the garage. This was going to be my biggest project to date. Up until now, I’d learned everything from YouTube and friends—my most complex solo job before this was a timing belt replacement on my IS300.

For this swap, I took a strategic approach: install supporting parts while the car was still drivable, saving the transmission swap for last.

🎥 For a step-by-step walkthrough, check out our How-To Guides.

Step 1: Relocating the Handbrake

I started by converting the parking brake to a pull-style handbrake using the Heat Lightning Handbrake Conversion Bracket. It’s designed to use a SC300/400 handbrake and mounts in an OEM-style location for a clean, factory finish.

Tools used: Basic socket set, trim removal tools
Time spent: ~1.5 hours

Step 2: Installing the Clutch Pedal Kit

Next, I installed the Heat Lightning Clutch Pedal Kit. No drilling required—it uses factory mounting points, which made the install way easier than expected. This set me up to be ready for the transmission install later on.

Pro tip: Test fit the master cylinder placement before tightening everything down.

Step 3: Removing the Automatic Transmission

This was the most labor-intensive part of the swap. The steps included:

Removing the full exhaust system from manifold to mufflers
Pulling the driveshaft
Draining the transmission fluid
Unbolting the torque converter via the bellhousing cover
Removing the shifter and loosening the motor mounts
Taking off the transmission crossmember
Disconnecting wiring and removing all bellhousing bolts
Finally, pulling the transmission

Tools used: Transmission jack, breaker bar, extensions
Time spent: ~6–8 hours with breaks

Step 4: Prepping & installing the W58

The shifter needed to be extended by about 3 inches to match the GS300 tunnel. That required lengthening both the housing and the shift rod inside the transmission.

Then, I installed a flywheel from an SC300 and an OEM SC300 clutch kit. This is also the perfect time to replace your rear main seal—don’t skip it.

For mounting, I used the Xcessive Manufacturing Transmission Crossmember. I ordered a custom driveshaft from Drift Motion and trimmed the transmission tunnel slightly to center the shifter properly.

Time spent: ~3–4 hours
Recommended: New transmission mount bushings

Step 5: Final Assembly & Startup

I connected the clutch master to the slave cylinder using the braided line from the Heat Lightning kit. After filling the transmission with fluid and bleeding the clutch, I jumped the neutral safety switch so the car could start.

Alternatively, you can install the ATEMU, which allows full VVT-i functionality and retains more OEM-style behavior.

Final Thoughts

This swap was a serious challenge—but one of the most rewarding things I’ve ever done. It taught me a ton about the platform and gave me confidence to take on even more ambitious projects.

If you're considering a W58 swap into your GS300, I say go for it. With a clear plan, quality parts, and a bit of patience, it’s completely doable—even if you're just wrenching in your driveway.

Parts & Tools Recap

Parts from Lunatics Co.:

Additional:

OEM SC300 flywheel & clutch kit
W58 transmission
Drift Motion custom driveshaft
Rear main seal (Toyota OEM recommended)

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