Beginning at the start of production for model year 2003, the 48RE transmission was introduced to the Dodge line of heavy-duty trucks. The 48RE is a new designation for the previous-design 46/47RE. There are numerous differences, including a redesigned pump stator and torque converter and increased capacity in the clutch drums. There was also a change in the hydraulics in the valve body in the torque-converter-clutch control circuit.
The reason for the change in the TCC circuit is so that TCC engagement will be possible in the Manual 2 and Manual 1 positions, providing better pulling capacity at lower engine speed. The TCC solenoid is now fed forward-clutch pressure instead of being fed from the 1-2 shift valve as in the previous design. This now makes it possible to have TCC in 1st gear. Refer to figures 1 and 2 for a partial hydraulic-circuit diagram of the TCC circuit.
The main changes were made in the channel plate and the two spacer plates and required the elimination of the No. 2 checkball. Refer to the figure descriptions below:
Figure 3 shows the previous-design 46RE/47RE main valve body and upper transfer plate and the checkball locations. There also are dotted circles around the areas that changed in the 48RE.
Figure 4 shows the main spacer plate on the 46RE/47RE, and the hole configuration for the No. 2 checkball.
Figure 5 shows the lower transfer plate and lower spacer plate on the 46RE/47RE, and the hole configuration for the No. 2 checkball to the spring side of the lockup and 3-4 shift valve and the second land of the lockup timing valve. It also shows the previous-design TCC-solenoid feed from the 1-2 shift valve.
Figure 6 shows the new-design 48RE main valve body and upper transfer plate and the checkball locations. Notice the elimination of the No. 2 checkball. Also, dotted circles indicate the areas that changed in the 48RE.
Figure 7 shows the main spacer plate on the 48RE, and the hole configuration for where the No. 2 checkball used to be. Notice that there are only three holes, which are square, compared with the previous plate shown in Figure 4.
Figure 8 shows the lower transfer plate and lower spacer plate on the 48RE; note that the hole configuration for the No. 2 checkball is eliminated. Also notice that the previous-design TCC-solenoid feed from the 1-2 shift valve has been eliminated and the new hole connects the slot in the channel plate to the forward-clutch circuit.
December 2008 Issue
Volume 25, No. 12
- Dodge 48RE: Valve-Body Hydraulic Differences
