ALLISON-OM1334EN

The HT 700 Series retarder, located between the torque converter and the transmission

gearing, provides hydraulic retardation capabilities to slow the vehicle. Maximum

retarder effect in this series occurs at high input speed. Selecting a lower hold range

position when using this type retarder is recommended for maximum effect.

Depending on the vehicle retarder apply system used, partial retarder application is

available when maximum application is not needed.

AUXILIARY TRANSMISSION

Select the desired auxiliary gear ratio while the vehicle is stopped. Do not shift the

auxiliary transmission while the vehicle is moving.

TWO-SPEED AXLE

The two-speed axle may be shifted from low to high or high to low while the

vehicle is moving without damaging the transmission. However, the axle or vehicle

manufacturer’s recommendations should be followed for shifting the axle. It is

recommended that axle shifts be made with the transmission in the highest range to

prevent a transmission range shift from coinciding with an axle shift.

TOWING OR PUSHING

PARKING BRAKE

On a vehicle with no

(Park) position on the transmission shift selector, always put

the selector in

(Neutral) and apply the parking brake (or emergency brake if the

vehicle is not equipped with a parking brake) to hold the vehicle when it is unattended.

CAUTION:

Failure to disconnect the driveline or remove the axle

shafts before towing or pushing can cause serious transmission

damage.

The engine cannot be started by towing or pushing. Before towing

or pushing a vehicle, disconnect the driveline or lift the drive

wheels off the road. If the vehicle is a motor coach, remove the axle

shafts from the drive wheels. When the axle shafts are removed, be

sure to cover the wheel openings to prevent loss of lubricant and en-

try of dust and dirt. An auxiliary air supply will usually be required

to actuate the vehicle brake system.

ALLISON AT, MT, HT SERIES ON-HIGHWAY TRANSMISSIONS

OPERATOR'S MANUAL

2000