Diesel Engine M A
Resume:
SUDDEN LOSS OF MOVEMENT
COMPLAINT:
CAUSE:
CORRECTION:
SERVICE INFORMATION:
A Ford F250 with the 6.7 Liter diesel engine and the 6R140W transmission has a complaint of a sudden loss of movement. According to the operator, the truck was driving along normally when a popping sound was heard and the truck then coasted to a stop and would not move in any range. The truck was towed to the transmission shop where the pan was dropped for inspection. The pan was clean, so the transmission was removed for inspection. Upon disassembly, no internal damage was found. The transmission was reassembled with a rebuilt torque converter, the truck would still not move.
A scan tool was connected, when data was displayed it was noticed that turbine rpm in park was less than engine rpm. When the transmission was placed in drive, there was a bump and the turbine speed sensor indicated zero rpm, but still no movement. With turbine rpm being zero in drive would indicate that the low reverse and 1-2-3-4 (FWD) clutch applied and the input shaft was not turning. This could be misleading because the turbine speed sensor is reading windows on the 1-2-3-4 (FWD) clutch housing refer to figure 1, not the input shaft. In other words, there is no mechanical connection to the output shaft. When the transmission was disassembled this time, internal components were inspected for breakage or stripped splines. At first nothing was obvious, so it was decided to disassemble the 1- 2-3-4/4-5-6 (OD) clutch housing even though it looked good, refer to figure 2. It wasn’t until the piston return spring was compressed and the retaining snap ring was removed that the problem showed itself. The input shaft had a clean break from the 4-5-6 (OD) clutch housing, refer to figure 3. As a side note this was a 2017 vehicle with only 40,000 miles showing. Replace the 4-5-6 (OD) clutch housing.
4-5-6 (OD) Clutch Housing BC3Z-7F207-C A special thank you to Steve at Downtown Transmission for sharing his experience and photos that made this bulletin possible.
52 " 2 0 1 9 ” S E M I N A R I N F O R M A T I O N Automatic Transmission Service Group
Figure 1
Copyright © 2019 ATSG
1-2-3-4 (FWD) CLUTCH HOUSING
4-5-6 (OD) CLUTCH HOUSING
Figure 2
Copyright © 2019 ATSG
THE TURBINE SPEED
SENSOR IS READING
THE WINDOWS ON THE
1-2-3-4 (FWD) DRUM
ALWAYS CHECK HERE FOR CRACKS
FORD 6R140W
SUDDEN LOSS OF MOVEMENT
" 2 0 1 9 ” S E M I N A R I N F O R M A T I O N 53 Automatic Transmission Service Group
Figure 3
Copyright © 2019 ATSG
4-5-6 (OD) CLUTCH HOUSING
THE SHAFT BREAKS OUT
OF THE CENTER OF THE
CLUTCH HOUSING
FORD 6R140W
SUDDEN LOSS OF MOVEMENT
54 " 2 0 1 9 ” S E M I N A R I N F O R M A T I O N Automatic Transmission Service Group
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