Park problems with Dodge RE transmissions

Dodge RE series transmissions originally began using a simple Park/Neutral Switch as seen in Figure 1. This switch rides on a cam located inside the transmission. The cam is part of the manual valve linkage and park rod (Figure 2). In 2002, the switch was replaced by a Transmission Range Sensor, as seen in Figure 3. To accommodate this change, the internal cam was redesigned (Figure 4). This also altered the geometry of the parking rod (Figure 5).

The original length with the three-pronged Park/Neutral Switch was approximately 14 3/4 inches in length. The Park rod for the new TRS is approximately 14 5/8 inches in length.

Interchanging these rods will interfere with the proper operation of a Park engagement. Additionally, the 48RE transmission in Dodge diesel application has a wider bullet base with which to wedge the park pawl into the park gear (Figure 6). The 46 and 47 RE units the width is 0.547 inch, while the 48RE is 0.724 inch.

This, too, needs to be observed when swapping out valve bodies or internal linkages for Park to engage correctly.

A common failure with the Transmission Range Sensor is the internal plunger bushing wearing, allowing transmission fluid to enter the sensor. The fluid will eventually load up the connector (Figure 7), causing range sensor signal problems. This signal is hard-wired into the instrument cluster. The instrument cluster then broadcasts this signal over the network to the computer controlling the transmission’s shifting. Because diagnostics could potentially become involved should signals become erratic, unplug the sensor for a quick visual before getting overly involved in the system.

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