otb 15b-11 mercedes 722.9 harsh engagements and shifts
TRANSCRIPT
Online Technical Bulletin
AUTOMATIC TRANSMISSION SERVICE GROUP15-B11Page 1 of 3
After rebuild or repairs, a 722.9 may at times experience a harsh engagement into reverse and/or no forward. It may be noticed that the first to second, fifth to sixth and sixth to seventh shift is also harsh.
One cause may be the use of an incorrect spacer plate. Some models eliminated the B1 and B3 check valves from the valve body (Figure 1). When this took place, two 0.155" holes were eliminated, one over each check valve were also eliminated (Figure 2). This will force B1 regulated clutch apply to pass through an approximate 0.078" orifice while the B3 will pass through an approximate 0.064" orifice to the clutch. If a spacer plate that requires these two check valves is used in a valve body where they have been eliminated, regulated clutch apply will be able to pass through the 0.155" hole applying the clutch prematurely causing the harsh shift sensation.
Install the correct spacer plate or install the B1 and B3 check valves.
COMPLAINT:
CAUSE:
CORRECTION:
HARSH ENGAGEMENTS AND SHIFTS
MERCEDES 722.9
AUTOMATIC TRANSMISSION SERVICE GROUP
Online Technical Bulletin
15-B11Page 2 of 3
K2 Clutch
B1 Clutch
K1 Clutch
BR Clutch
B3 Clutch
TCM Cooler Pressure
Check Valve 1
K3 Clutch
TCM Cooler Pressure
Check Valve 2
X
X
Copyright © 2015 ATSG
Figure 1
HARSH ENGAGEMENTS AND SHIFTS
MERCEDES 722.9
AUTOMATIC TRANSMISSION SERVICE GROUP
Online Technical Bulletin
15-B11Page 3 of 3
B1 CheckValve HoleEliminated
B3 CheckValve HoleEliminated
Figure 2
Copyright © 2015 ATSG
HARSH ENGAGEMENTS AND SHIFTS
MERCEDES 722.9