Manual Fourth - 4th Gear - Forward, at any time, whenever the vehicle is driven in Forward, you can choose this gear. But TCM controls prevents transmission to shift to 5th gear. When the shift lever shifts from Overdrive (D) to Forward (4), the manual valve will move, too. The following changes will occur in the hydraulic and electrical systems:

Manual Valve: The manual valve is only used to open the transmission manual shift shaft switch assembly. The transmission manual shift shaft switch assembly sends signal to TCM and indicate transmission in manual 4th gear. In the manual valve, there is no hydraulic difference between overdrive and manual 4th gear.

4-5 SS Valve: 4-5 SS valve is energized to allow the feed limit fluid to flow into the 4-5 signal fluid passage. 4-5 signal fluid overcomes 4-5 shift valve spring (373) tension to move 4-5 shift control valve (375) and 4-5 shift valve (374) to the applied position.

4-5 Shift Valve: 4-5 fluid is prevented in 4-5 shift valve (374) and the Overdrive Clutch No. 2 feed fluid is drained.

Overdrive Clutch Assembly: Overdrive clutch fluid is drained from the overdrive clutch piston to the release overdrive clutch plate.

#12 Ball Check Valve: Overdrive clutch fluid positions the #12 ball check valve against the overdrive clutch No. 1 feed circuit, flows into the overdrive clutch No. 2 feed circuit, and is drained from 4-5 shift valve.

Overdrive Clutch Accumulator: Overdrive clutch fluid is also drained from the overdrive clutch accumulator assembly. Accumulator fluid makes the overdrive clutch accumulator piston overcome the accumulator spring tension to prepare for Overdrive Clutch apply once again.

4-5 Shift Valve: Coast clutch feed fluid flows into the coast clutch fluid circuit through the 4-5 shift valve (374).

Coast Clutch: The coast clutch fluid is sent to the coast clutch piston to apply coast clutch plate.

Manual Fourth - 4th Gear, when the vehicle is driven in Overdrive - 5th Gear and the transmission clutch applies, if you choose Manual Fourth, then the TCC cannot release. Under normal operating conditions, the operation of TCC in Manual Fourth - 4th Gear is the same as in Overdrive - 4th Gear.