Big, Heavy, Strong MT643

The MT-640 and 643 Allison Transmission is used in heavy vehicles that require that extra punch not available on other units. It is used in buses, trucks and other heavy vehicles.

The rebuild kit is available as an Overhaul Kit, Banner Kit and Master Kit. Friction and Steel Plates can be purchased separately. The Overhaul kit comes with the Armstrong gasket and Vespel Rings.

The filter pictured below is the standard filter for this unit (paper with large grommet hole). There is also a paper filter with small grommet hole and the stainless steel wire mesh for 5" pan used with auxiliary filter. There is also the spin on cartridge, governor and center support filters.

Bushing are available as follows:

- Bushing Kit
- Pump
- Center Support
- Center Sun Gear
- Front Planet Carrier
- Low Planetary Carrier
- Rear Output Shaft (Replaces Bearing)

The pump bushing comes in 2.443, 2.530, 2.580" inches in overall diameter. Always take some time to check the external cooler to make sure it is functioning properly as it is a critical part for the life of the unit.

The Durable AT545 and its Parts...

Here is another posting on AT-545. The filter is the same for the 540 and 543 and covers all years of production (1970-Up). The filter is available in the metal screen, treated paper and brass type. You can also update the filter to the same one the MT643 uses; you will also need to order a tube for the update. Don't forget to order the external filter cartridge too.

The bushing in the picture below is the front pump bushing. This tends to be the most ordered single bushing outside of the bushing kit. Here is a list of bushings available:

- Pump Body / Bronze or Babbitt
- Stator / Front
- Sun Gear / Front and Rear 1.120" or 1.190" Overall Diameter (depends on serial number)
- Center Support / 1.540" or 1.600" Overall Diameter
- Front Planet
- Output Shaft / 0.775" or 0.815" Overall Diameter (depends on serial number)

The bushing kit is broken down by AT540, 543 & 545 early years and 545 later years; both containing 7 bushings in the kit.

Allison 700 Series Transmission

The Allison 700 Series transmission is used in buses and trucks. The banner kit is compatible with all units in the series (700, 740, 750, 754...). Due to weight, the master kit is not available; the steels that would come in the master kit are available individually. The lockup friction and the backing plate for the lockup clutch are not included in the kit and should be ordered separately as required.

There is an internal and external filter. The internal filter comes with a 6" or 7" pickup tube. The external spin-on filter has a 2 quart capacity and is fitted with or without the adapter. Bushings, thrust washers can be ordered individually, there is a sealing ring kit too.

The pump come in two different configurations, two gear or three gear. Other pump parts and hard parts are now in stock. Please call if you have any questions or need to order Allison Parts.

Allison 500 Series Automatic Transmission

The Allison 500 Series transmission is an automatic transmission that is manufactured by General Motors. It is used in medium duty vehicles. For example, regular, dump and small concrete trucks; they are also used in delivery trucks and some buses.

The AT500 Allisons does not have a "park" feature built in to them like an automatic transmission that you would find in a passenger vehicle. The park is customarily achieved through an air brake system used in the truck for its regular braking system.

Some of the units also contain a power take off (PTO) option that allows the connection of a separate system where it draws its power directly from the transmission. Lets say you have a dump truck, the hydraulic system that powers the piston to lift the bed is powered through the PTO.

Besides being very popular in its home market of the U.S. it is also popular in Canada and Mexico. In Central America, most notably in Panama, Nicaragua and Guatemala; In South America, most notably in Argentina, Peru, Colombia, Chile, and Venezuela. It is also used in most major markets around the world.

There are several different versions of the Allison 500 Series Transmission

AT540
AT543
AT545

MT650 and MT653 Transmission Parts

The Allison MT 650 and 653 gear box use the same transmission rebuild kit and other parts. Here are some pictures.

Bushing Kit


Gasket and Seal Kit


Friction Plates (Clutches)


Steel Plates


Filter

Allison HT 740, 750 Transmission Parts

Transmission Parts and Rebuild Kit Prices:

Allison HT740, HT750

For information on prices click here.

2001-Up
Overhaul Kit
Banner Kit
Master Kit

Filter
Filter, w/ 7" Pan

Service Manual, HT700 Series

Pump Assembly, 2 Gear 700 Series
Pump Assembly, 3 Gear CLBT754

Torque Converter

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