Gear Vendors Overdrive Installation

We're installing the Gear Vendors overdrive in a Top Loader four-speed car. Bill supports the transmission with a screw jack to remove the mount and crossmember.

The Top Loader tailshaft housing is removed next. Gear Vendors supplies its own tailshaft, but don't throw away your original tailshaft housing-put it away for safekeeping. This is a good time to change transmission lube or fluid, which should be changed every 30,000 miles or three years, whichever comes first.

Gear Vendors provides a new tailshaft housing gasket. Make sure contact surfaces are clean. Do not use sealer.

Gear Vendors overdrive is tied to our Top Loader via this provided tailshaft housing. Because this car has a Hurst shifter, the Hurst adaptor plate is transferred from the Top Loader tailshaft housing to the Gear Vendors housing. Use Loctite on bolt threads.

The Gear Vendors tailshaft housing is installed, with the bolts torqued to the specifications....

....found in your Ford Shop Manual. Tighten bolts uniformly in a criss-cross fashion.

This coupling slides in to engage the Top Loader's tailshaft splines. Lubricate the coupling and seal with automatic transmission lube before installation.

Gear Vendors suggests .040-inch of shaft endplay between the overdrive unit and....

....Top Loader tailshaft at the coupling. Shims are provided to ensure you get .040-inch.

Check this out-the Gear Vendors overdrive unit is so light you can hold it in your hands, yet it's guaranteed up to 1,200 horsepower. Gear Vendors can build it to withstand 2,000 hp.

The Gear Vendors overdrive unit is splined into the tailshaft housing. Eight threaded 1/4-inch studs with locknuts secure the installation.

Installed, our Gear Vendors overdrive fits snuggly between exhaust headers and pipes. Don't forget to service your Gear Vendors unit with automatic transmission fluid via the fill plug provided at 3 o'clock as you face the overdrive from behind.

The Hurst shifter bolts into place in the same location. Ford shifters work fine with the Gear Vendors overdrive.

On the left is the overdrive engagement solenoid. The white lead from the control module connects here to energize the solenoid. It can energize automatically or manually based on the mode you choose.

A speed sensor (pulse generator) driven off the speedometer cable provides vehicle speed input for system function.

This 90-degree speedometer drive unit makes it easier to install Gear Vendors in a Mustang due to tight transmission tunnel clearances.

The Gear Vendors 90-degree cable adaptor makes it easier to connect the speedometer cable to the overdrive where clearances are tight.

Unit activation wiring can be routed any number of ways, including via a 1/2-inch hole with a grommet. Mustangs & Fast Fords OC has routed the wiring through the shifter passage mid-tunnel as shown. By the way, always ensure your Gear Vendors overdrive electrical system is protected with a 30-amp fuse.

Your driveshaft will need to be shortened by a professional driveshaft company. Mustangs & Fast Fords OC elected to install a new Inland Empire Driveline driveshaft from Mustangs Plus. This is a new steel shaft designed to take a lot of torque. It has been checked for run out and dynamic balanced for smoothness.