Dodge Omni/Horizon/Rampage 1978-1989 Repair Guide

Automatic Transaxle



Dexron®II or it's superseding type transaxle fluid is used in the automatic transaxles.


Vehicles 1978 through 1982 automatic transaxles have 2 separate reservoirs that require filling separately. The 1983 and later models fill as one unit. Most models have a drain and fill plug in the differential cover; some models will have only a fill plug. Should it become necessary to drain the differential and the cover has only a fill plug, simply remove the cover to drain. A service gasket, should be formed from RTV sealant when the cover is installed. Use a 1 / 16 in. (2mm) bead of RTV sealant on the cover.

To check the fluid level, remove the filler plug. The level should be at the bottom of the hole, which can be checked with your finger or a piece of bent wire.

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Fig. Fig. 1 The level should be between the ADD and FULL marks on the dipstick


RTV silicone sealer is used in place of a pan gasket.

Chrysler recommends no fluid or filter changes under normal usage of the car. Severe usage requires a fluid and filter change every 15,000 miles (24,135 km). Severe usage is defined as:

More than 50% heavy city traffic during 90° or higher weather.
Police, taxi or commercial operation or trailer towing.

When changing the fluid, only Dexron®II or it's superseding type fluid should be used. A filter change should be performed at every fluid change.

  1. Raise the vehicle and support it on jackstands.
  3. Place a large container under the pan, loosen the pan bolts and tap at one corner to break it loose. Drain the fluid.

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Fig. Fig. 2 An extension is helpful in removing the pan bolts

  1. When the fluid is drained remove the pan bolts.

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Fig. Fig. 3 Once the fluid is drained, remove the pan

  1. Remove the retaining screws and replace the filter. Tighten the screws to 35 inch lbs. (4 Nm).

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Fig. Fig. 4 Remove the retaining screw, then replace the filter with a new one

  1. Clean the fluid pan, peel off the old RTV silicone sealer and install the pan, using a 1 / 8 in. (3mm) bead of new RTV sealer. Always run the sealer bead inside the bolt holes. Tighten the pan bolts to 10-12 ft. lbs. (13-16 Nm).
  3. Pour four quarts of Dexron®II or it's superseding type. fluid through the filler tube.
  5. Start the engine and idle it for at least 2 minutes. Set the parking brake and move the selector through each position, ending in Park.
  7. Add sufficient fluid to bring the level to the FULL mark on the dipstick. The level should be checked in Park, with the engine idling at normal operating temperature.