Automatic Models HT 740
up to 445 nhp (332 kW)

SPECIFICATIONS

Cross-Section | Features & Benefits | Typical Applications | SCAAN Specification Assistance

General rating+

Net input power (max).............................445 hp (332 kW)
Input speed range................................1900 - 2400 rpm
Net input torque (max)......................1435 lb ft (1946 N�m)
Vehicle weight (max)............Up to 80,000 lbs (36,287 kg) GVW
                                 and 130,000 lbs (58,967 kg) GCW    

Mounting

Direct..............SAE 1 flywheel housing with flex plate drive
Remote.....Converter housing side pads, and rear housing top pad    

Torque converter

Type..........................Single-stage, 3-element, polyphase
Stall torque ratio.........TC 487-1.50; TC 488-1.70; TC 497-2.72;
                           TC 470-2.83; TC 495-2.39; TC 496-1.78;
                                        TC 498-2.45; TC 499-1.91
Automatic lockup clutch..........Effective in all forward ranges
                          or effective in 2nd through 4th ranges
                                       – depending on model used    

Gearing

Type.........................Constant mesh, spur type, planetary
         Range                                  Ratios*:
         First...................................3.69:1
         Second..................................2.02:1
         Third...................................1.38:1
         Fourth..................................1.00:1
         Reverse.................................6.04:1
           * Gear ratio does not include torque converter ratio.    

Power takeoff provision

Converter driven (SAE 6-bolt)
Location................10 o'clock position (as viewed from rear)
Drive gear ratio............................1.00 x turbine speed
Drive gear rating.................300 lb ft (407 N�m) continuous; 
                                400 lb ft (543 N�m) intermittent
Engine driven (optional) (SAE 8-bolt)
Location....converter housing: one at 1 o'clock position and one
                      at 8 o'clock position (as viewed from rear)
Drive gear ratio.......1 o'clock position – 1.35 x turbine speed;
                       8 o'clock position – 0.84 x turbine speed
Drive gear rating.................200 lb ft (149 N�m) continuous; 
                                260 lb ft (194 N�m) intermittent    

Oil system

Oil type..........................................Dexron II�, C4
Capacity 
       (excluding external circuit)...7.5 U.S. gals (28.5 liters)
                                                 (w/std. oil pan)
Filter..................................External, remote mounted 
Cooler............................................Remote mounted 
(Filter and Cooler not furnished on transmission assembly but is supplied
 by vehicle manufacturer.)    

Size

                                                             
Length..........................................37.4 in (950 mm)
Width...........................................21.7 in (552 mm)
Height..........................................26.6 in (675 mm)
Weight (dry)..........................840 lbs (381 kg) (approx.)
+NOTE: Vocational ratings may vary by vocation.     

 

Transmission Cross-section (go to top)

Design Features & Benefits (go to top)

Designed for use with diesel engines up to 445 nhp (332 kW). Four forward ranges and one reverse. This transmission model is best suited for medium- and heavy-duty trucks and buses.
Clutches are multidisc design, oil-cooled, hydraulically-operated, and self-compensating for normal wear. Spur-type planetary gears are designed for strength, quietness, and long life.
Automatic lockup clutch, throttle-modulated for maximized fuel economy and enhanced engine braking. Automatic upshifting and downshifting within each drive range. Built-in inhibitors prevent downshifts or shifts into reverse unless vehicle speed is within an acceptable range.
The Allison three-element torque converter provides smooth, shock-free operation. A choice of converters permits matching the HT 740 to a wide variety of engines.
Converter-driven power takeoff drive on right side of transmission (as viewed from the rear) is standard. Design is SAE 6-bolt.
Optional engine-driven power takeoff is available in two locations - upper right and lower left sides, as viewed from rear. Design is SAE 8-bolt.
Provisions for neutral start switch, reverse signal switch, SAE regular-duty thread-type speedometer drive, electronic speedometer drive, and parking brake.
7.0 inch oil pan is standard. Optional 6.0, 4.5 and 8.5 inch pans are available when ground clearance or heavy duty operation dictates their use.

 

Typical Applications (go to top)

Dump Truck
Refuse Hauler
Lowboy Truck
Hook & Ladder Truck
Transit Mixer
Fire Truck
Logging Truck
Rear Loader (Refuse)
Agricultural
Motorhome
Construction Equipment Hauler
Wrecker (Tandem Axle)
Public Utility (All Wheel Drive Tandem Axle)
Other applications are available.

SCAAN Specification Assistance (go to top)

To be sure that you get the most efficient engine/transmission package for your operation in your territory with your preferred vehicle, your local Allison Transmission distributor offers SCAAN.

SCAAN stands for System for Computerized Application ANalysis and helps take the guesswork out of vehicle-buying decisions. What's more, it does so quickly and accurately through computer terminals located at all distributor outlets. This means rapid analysis of your vehicle needs on the spot.

SCAAN can compute a wide variety of vehicle performance parameters, including gradeability, acceleration and retardation. SCAAN will also check your powertrain specifications against Allison Transmission vocational experience to insure satisfactory vehicle performance.

SCAAN is user friendly. Interactive operation allows alternate vehicle configurations to be quickly evaluated to insure optimized powertrain selection.

 

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