ALLISON-OM1334EN

FLUID CONTAMINATION

Examine at Fluid Change

At each fluid change, examine the fluid which is drained for evidence of dirt or engine

coolant (water). A normal amount of condensation will emulsify in the fluid during

operation of the transmission. However, if there is evidence of coolant, check the

cooler (heat exchanger) for leakage between the cooler and fluid areas. Fluid in the

coolant side of the cooler (heat exchanger) is another sign of leakage. This, however,

may indicate leakage from the engine oil system.

Metal Particles

Metal particles in the fluid (except for the minute particles normally trapped in the

filter) indicate damage has occurred in the transmission. When these particles are

Transmission

Application

Fluid Change

Internal Sump

Filter

Governor

Filter

External

Auxiliary Filter**

MT 643R

After first

5000 miles

(8000 km) then

at 20,000 miles

(32 000 km) or

12 months*

Paper Filter:

At every other fluid

change

Stainless Steel Screen:

At overhaul

20,000 miles

(32 000 km)

or 12 months*

After first 5000 miles

(8000 km) then at

each fluid change

thereafter*

MT 600 Series

(Off-Highway)

1000 hours

maximum

or 12 months*

Paper Filter:

1000 hours maximum or

12 months*

Stainless Steel Screen:

At overhaul

1000 hours

maximum or

12 months*

After first 500 hours

and at normal oil

change intervals,

thereafter

HT 700 Series

(All Applications)

50,000 miles

(80 000 km) or

12 months or

1200 hours*

At overhaul

After first 5000 miles

(8000 km) and at each

25,000 miles

(40 000 km) or

6 months or

600 hours, thereafter*

* Whichever occurs first.

** An Allison high-efficiency filter may be used until the Change Filter light indicates it is

contaminated or until it has been in use for 3 years, whichever occurs first. No mileage restrictions

apply.

CAUTION:

Whenever excessive metal contamination has oc-

curred, replacement of the cooler and replacement of all bearings

within the transmission is recommended.

Table 3. Fluid and Filter Change Intervals

(cont’d)

ALLISON AT, MT, HT SERIES ON-HIGHWAY TRANSMISSIONS

OPERATOR'S MANUAL

2000