Rotary Valve: Reassembly

1977 GMC Forward Control 7.4L Eng VIN Y, Automatic Trans, Trans Mfr CD 475/M40SECTION Reassembly

Lubricate dampener "O" ring with power steering fluid and install on spool. Insert spool into valve body using a turning motion, until spool is even with valve body bottom and drive pin hole is directly opposite the deep notch in valve body. Install input shaft into valve spool, making sure drive pin holes are aligned. Insert drive pin into hole in valve spool and pull assembly into valve body, keeping cap slot and body pin aligned.

NOTE: Cap is seated correctly when top surface of cap is at least 3/32" below deep notch in valve body.

Install cap-to-body "O" ring.

Fig 1: Aligning Pin and Notch for Input (Stub) Shaft
G09341691Courtesy of NOT AVAILABLE
RENDER: 1.0x

NO RELATED

Recommended Tools & Savings

Use the Manual With the Right Hardware

Pair factory procedures with proven DIY tools so the instructions are easier to execute.

Affiliate disclosure: We may earn a commission at no extra cost to you.

When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • β€’ You smell fuel, burning insulation, or see smoke.
  • β€’ Brakes feel soft, pull hard to one side, or make grinding noises.
  • β€’ The engine overheats, stalls repeatedly, or misfires under load.
  • β€’ You are missing required tools, torque specs, or safe lifting equipment.
  • β€’ You are not confident in the next step or safety outcome.