Subaru 4AT
Phase 2 Part 1
Phase 2 Part 1
One of the more-frequently asked questions
in calls ATSG receives regarding the Subaru 4AT Phase 2
transmission is, “Where do the leaf springs go for the
2/4-clutch and low/reverse-clutch-pack stack-up?” Figures
1 and 2 show the position and configuration for the 2/4 pack,
and figures 3 and 4 on page 12 show the low/reverse pack.
The next-most-asked question has to do with
solenoid identification and specification. In Figure 5, the TCC
duty solenoid can be identified by the blue connector, the
low-clutch timing solenoid has the gray connector, and the
red/pink connector is for the pressure-control solenoid.
In Figure 6 the green connector identifies
shift solenoid 1 and the yellow connector identifies shift
solenoid 2.
The black connector shown in Figure 7
identifies the 2/4-brake timing solenoid and the red/pink
connector identifies the 2/4-brake duty solenoid. Also shown in
Figure 7 is the transmission-fluid-temperature (TFT) sensor
snapped in place where the ground wire for the 2/4 duty
solenoid is attached.
Figure 8 on page 18 provides a connector
pin-out and a solenoid resistance chart.
One of the many differences between the
Subaru 4AT and the 4AT Phase 2 is that the transfer-clutch
solenoid and valve-body assembly now are mounted on the back
side of the main case instead of being in the extension housing
(see Figure 9 on page 18). A change was made to this solenoid
and valve-body assembly, as illustrated in figures 10 through
14. The change reduced what Subaru describes as oil-pressure
vibration in its bulletin numbered 16-67-04. Although the
solenoid, the valve and valve-body assembly have been
redesigned, the spacer plate did not change (see Figure 15).
Figure 16 is an oil schematic that shows in
part the difference between the previous-design and the
updated-design transfer solenoid, valve and valve-body housing
while still using the original spacer plate. The part number
for this updated assembly is 31942AA130. 
©2006 Transmission Digest
