Our first experience with the new Gearstar 200-4R transmission was at this year’s Run To The Coast event in El Toro, California. We easily racked up well over 160 miles in one day without so much as a hiccup. We cruised effortlessly at 75 mph at 2,300 rpm, and the transmission was smooth, providing us with instant downshifting whenever we got throttle happy. As soon as the converter locked up it was like another gear. While we don’t have exact mileage numbers, we can tell you cruising over 1,000-rpm less than before in the fast lane has saved us numerous trips to the gas station. We’re only kicking ourselves for not doing this sooner. If you’re still slushing around in a three-speed with no overdrive, get on track and upgrade. You won’t regret it!
The Parts Bin
| Mfg. | Description | PN | Cost |
| Gearstar | Complete 200-4R Level III lockup/nonelectronic | NA | 3,195 |
| Polyurethane transmission mount | Call | 28 |
| G-Force | ’68-74 transmission crossmember for 200-4R | RCF1-400 | 219 |
With our fresh transmission...
With our fresh transmission mounted on the crossmember and supported by a hydraulic jack, all that’s left is to drop in the engine and bolt it up for final fitment.
Using new Grade 8, 7/16x 11/2-inch...
Using new Grade 8, 7/16x 11/2-inch hardware, we mounted the 200-4R transmission to the back of the block and used a 9/16-inch open wrench to secure it into place.
Be careful to avoid any wires...
Be careful to avoid any wires or lines that may be lingering between the transmission case and body of the chassis. While lining up the motor and transmission, we made that mistake and had to replace this section of wiring.
Once the motor is secured...
Once the motor is secured to the transmission, we could then fasten the torque converter to the flexplate. We applied a small amount of Loctite to the threads to help prevent them from backing out.
Installing the transmission...
Installing the transmission shifter bracket onto the oil pan rail required using the inner elongated boltholes. Then, we ran the shifter cable through to the GM lever and attached it to the “C” hole. Note: Trimming of the bracket may be necessary to fit on cast-aluminum pans.
Modifying the shifter was...
Modifying the shifter was one of the last steps to convert from our TH350 to the new four-speed, 200-4R. We simply removed the shroud from our TCI Automotive ratchet shifter and pulled the small pin out of the shifter mechanism to access all four gears through the shifter.
Before we took our first testdrive,...
Before we took our first testdrive, we filled the transmission with Royal Purple’s high-quality Max ATF synthetic fluid. It’s specifically designed for high-performance applications like ours and protects against heat and friction.
Worried about lockup on the...
Worried about lockup on the converter? Gearstar provides this vacuum switch, which is controlled by engine vacuum. It prevents lockup under full throttle and extends it in Fourth gear only at highway speeds. It also disengages lockup prior to a Fourth to Third gear downshift, too. Also, it’s adjustable and can be tuned to your driving style with the supplied Allen wrench.