The heavy duty 5-speed, (originally a Toyota Dyna truck gearbox) when fitted with the new adaptor, gearbox top, selectors and main output shaft etc will directly replace the Hilux/4-Runner 5-speed gearbox.

Marks 4WD Adaptors fully dismantled the gearbox and recondition it using all new bearings, seals etc. A new rear housing is fitted to the gearbox so that the vehicle’s original transfer case can be retained. The main output shaft in the gearbox is replaced with one that allows the Hilux/4-Runner coupling sleeve to mate it to the transfer case.

Marks 4WD Adaptors manufacture a special gear lever housing that has been designed to accept the standard Hilux/4-Runner 4-speed diesel and 5-speed diesel or petrol gear lever. The housing also allows the gear lever to emerge through the same hole in the transmission tunnel.

The heavy-duty 5-speed gearbox features a low 1st gear, which is ideal for rock crawling and general four wheel driving.

The gearbox has the following ratios:       1st 5.15:1 2nd 2.87:1 3rd 1.50:1 4th 1:1 and 5th 0.83:1 or 17% overdrive.

This gearbox has the same bolt pattern as the R151 gearbox found in the 3ltr diesel, 3ltr and 3.4ltr petrol Hilux, Surf and Prado vehicles.

Information When replacing Hilux 4-speed transmissions

The heavy-duty 5-speed gearbox can be used to replace the Hilux 4-speed fitted to early model vehicles.

The overall transmission assembly measures 130mm/5.1" longer than the original 4-speed diesel transmission and therefore will require the transfer case and crossmember to be relocated.

Crossmember mounting brackets are supplied with the kit to enable the transfer case to be relocated. The crossmember mounts also lower the transmission away from the floor pan, reducing drive line angles and allowing more transmission to floor pan clearance.

The transfer case shift lever also moves 130mm/5.1" back in the floor pan. For this reason, new floor cover plates and shift lever boots with chrome surrounds are supplied with the kit giving a professional finish.

The 4-speed petrol gear lever cannot be used with this transmission, only the 4-speed diesel and 5-speed gear levers are compatible with our gearbox selector housing. If you are replacing a 4-speed you will need to purchase a suitable lever.

If you fit the heavy-duty 5-speed gearbox, a bellhousing kit or adaptor plate will be required. See bellhousing listing below.

Information When replacing Hilux/4-Runner/Surf 5-speed transmissions

The heavy duty 5-speed will not fit the current model chain drive transfer case.

The bolt pattern on the front of the heavy duty 5 speed is different to the Hilux/4-Runner 5-speed.

Marks 4WD Adaptors manufacture an adaptor plate that converts the heavy-duty 5-speed bolt pattern to the Toyota Hilux/4-Runner 5-speed bolt pattern. This adaptor plate is not compatible with 4-speed transmissions.

If you install a new engine along with the heavy-duty 5-speed gearbox, a new bellhousing kit is required.

Gear Lever

The 5-speed Hilux/4Runner diesel or petrol model gear lever can be used with this transmission, however the gear lever from the 2.4ltr diesel Surf is different therefore a lever from the above mentioned will need to be purchased.

HEAVY DUTY 5-SPEED GEARBOX KITS

HEAVY DUTY 5-SPEED BELLHOUSING INFORMATION

The bellhousing has been designed to accept the Toyota petrol pressed metal clutch fork, clutch fork pivot, clutch fork boot and slave cylinder (mounted on the right hand side). When replacing the Toyota diesel engine a petrol model slave cylinder will need to be purchased. The Toyota clutch master cylinder is retained for the conversion.

We recommend using a standard GM 10" or 10.5"pressure plate with a Toyota 10" clutch disc.

The standard GM flywheel with153 tooth ring gear must be used. The GM flywheel with 168 teeth will not fit inside the bellhousing. A reduction drive starter motor could be used to obtain more driveline to starter clearance.

The GM engine can be fitted to the vehicle without the need to reposition the transmission, modify the firewall or alter drive shaft lengths.

 Engine mounts are available for GM V6 and V8 engine conversion kits. The engine mount brackets have been designed to bolt to the engine block and fit to the Toyota mounting rubbers. 18R petrol and diesel engine chassis posts remain in their original position. Vehicles originally fitted with 3Y, 4Y and 22R engines require new chassis posts.