A/T - Burned 3-4 Clutch/High 2-3 Shifts
Number 85-7-3 Date 10/84Subject: BURNED 3-4 CLUTCH, AND/OR HIGH 2-3 SHIFTS ALL 1982 THRU 1985 THM 700-R4
"Please discard previous bulletin 84-7-18 due to text change."
FIGURE 7 - INPUT CLUTCH HOUSING:
Starting production of all 1985 THM 700-R4 transmissions an air bleed orifice cup plug was added to the input clutch housing (Figure 7). Due to this change the procedure listed below for air checking the 3-4 clutch piston and the check ball has been revised.
Some 1982 thru 1984 THM 700-R4 transmissions may exhibit a burned 3-4 clutch, and/or high 2-3 shifts. (The high 2-3 shifts are experienced on C, K, and G truck gas/diesel applications only).
FIGURE 5 - TRANSMISSION IDENTIFICATION:
FIGURE 6 - THM 700-R4 TRANSMISSION - I.D. LOCATION:
Starting January 15, (Julian date 015) 1984, all THM 700-R4 transmissions were built with a new input housing and shaft assembly and control valve body assembly. Refer to Figures 5 and 6 for Julian date location.
FIGURE 1 - FORMER INPUT HOUSING & SHAFT ASSEMBLY:
FIGURE 2 - NEW INPUT HOUSING & SHAFT ASSEMBLY:
The former input housing and shaft assembly had a check ball seat drilled into the housing. A check ball was installed into this hold and the opening was then staked to retain the ball (see Figure 1).
The new input housing and shaft assembly has a check valve retainer and ball assembly which is pressed into the housing (see Figure 2).
Only the new input housing and shaft assembly is available for service. Refer to the parts manual for correct part numbers and model application.
FIGURE 2 - NEW INPUT HOUSING & SHAFT ASSEMBLY:
FIGURE 4 - AIR CHECK OF HOUSING & SHAFT ASSEMBLY:
Also, for the burned 3-4 clutch, air check the 3rd and 4th clutch piston and the check ball in the input clutch housing for leaks by following the procedure as listed below:
1. If you have an input clutch housing which does not have the new air bleed orifice cup plug (Figure 2) then, place your thumb firmly over the oil hole on the turbine shaft shown in Figure 4.
FIGURE 7 - INPUT CLUTCH HOUSING:
FIGURE 8 - INPUT CLUTCH HOUSING:
2. If you have an input clutch housing which has the new air bleed orifice cup plug (Figure 7) then, place your middle finger over the air bleed orifice cup plug and your index finger over the oil hole on the turbine shaft as shown in Figure 8.
FIGURE 4 - AIR CHECK OF HOUSING & SHAFT ASSEMBLY:
3. Place the nozzle of an air gun over the check valve hole shown in Figure 4.
4. Inject a short blast of air into the check valve hole.
5. After injecting the air into the check valve hole, release your thumb off the oil hole on the turbine shaft. As you remove your thumb off the oil hole, you should hear air escape.
6. If you do not hear air escape from the oil hole, remove the third and fourth clutch piston assembly and inspect it for damage. Also, check the check ball for proper sealing. If you hear air escape from the oil hole, the piston assembly and the check valve are good.
FIGURE 3 - NEW CONTROL VALVE BODY ASSEMBLY:
The new control valve body assembly is for the burned 3-4 clutch, and the high 2-3 shifts which are experienced on the C, K, and G, trucks gas/diesel applications only. The new control valve body assembly is identified with an "X" on the casting (see Figure 3 ) to distinguish it from the past control valve body assembly.
Only the new control valve body assembly is available for service. Refer to the parts manual for correct part numbers and model applications.