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Ryan Schott
Ryan Schott,
Category: GMC
Satisfied Customers: 82
Experience:  technician at Demarois Buick Gmc
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2004 GMC Yukon 4x4. 5.3l transmission went out no 3rd or

Customer Question

2004 GMC Yukon 4x4. 5.3l transmission went out no 3rd or reverse. had transmission completely rebuilt by a transmission shop. We installed it filled it with DEX VI. Transmission sluggish when shifting and sometimes taking way to long, but if I goose it shifts fine. Any ideas?
Submitted: 4 months ago.
Category: GMC
Expert:  Ryan Schott replied 4 months ago.

Are you able to reset the shift adapts? You need a tech 2 to do it but if you don't it will shift odd. Even after the reset it will take a little bit of driving for it to relearn values.

Customer: replied 4 months ago.
Are you sure? because I have done over 10 others with no problem
Expert:  Ryan Schott replied 4 months ago.

I have done some that didn't need it and others that would barely work if i didn't, it all depends how long it was driven while it was going out, the adaptive pressures may have gotten very bad, it may not be the issue but i always start there before pulling a tranny again. Otherwise you will want to take it back to the rebuilder because if you cut into it too much it will void any warranty.

Customer: replied 4 months ago.
I have reset the adapters, still shifts funny, how long to relearn?
Expert:  Ryan Schott replied 4 months ago.

20 miles in varying conditions, they recommend the road test procedure i can send you it, it's kind of long. After a TAP reset though it will have long shifts on normal throttle for a bit.

heres the road test

Upshift Control and Torque Converter Clutch (TCC) Apply

The PCM calculates the upshift points based primarily on two inputs: throttle angle and vehicle speed. When the PCM determines that conditions are met for a shift to occur, the PCM commands the shift by closing or opening the ground circuit for the appropriate solenoid.

Perform the following steps:

Important: This transmission is equipped with an electronically controlled capacity clutch (ECCC). The pressure plate does not fully lock to the torque converter cover. Instead, the pressure plate maintains a small amount of slippage, about 20 RPM, in SECOND, THIRD and FOURTH gears, depending on the vehicle application. ECCC was developed to reduce the possibility of noise, vibration or chuggle caused by TCC apply. Typical apply speeds are 49–52 km/h (30–32 mph) in THIRD gear and 65–73 km/h (40–45 mph) in FOURTH gear. Full lockup is available at highway speeds on some applications.

Important: The TCC will not engage until the engine is in closed loop operation and the vehicle speed is as shown in the Shift Speed table. Refer to Shift Speed. The vehicle must be in a near-cruise condition, not accelerating or coasting, and on a level road surface.

  1. Refer to the Shift Speed and choose a throttle position of 12 percent, 25 percent or 50 percent. All throttle angles shown should be tested to cover the normal driving range.
  2. Monitor the following scan tool parameters:
    • Throttle angle
    • Vehicle speed
    • Engine speed
    • Output shaft speed
    • Commanded gear
    • Slip speed
    • Solenoid states
  3. Place the gear selector in the OVERDRIVE position.
  4. Accelerate the vehicle using the chosen throttle angle. Hold the throttle steady.
  5. As the transmission upshifts, note the vehicle speed when the shift occurs for each gear change. There should be a noticeable shift feel or engine speed change within 1 to 2 seconds of the commanded gear change.
  6. Compare the shift speeds to the Shift Speed table. Refer to Shift Speed. Shift speeds may vary slightly due to transmission fluid temperature or hydraulic delays in responding to electronic controls.
    • Note any harsh, soft or delayed shifts or slipping.
    • Note any noise or vibration.
  7. Repeat steps 1 through 6 to complete all throttle angles.
  8. Check for TCC apply in THIRD and FOURTH gear.
    • Note the TCC apply point. When the TCC applies there should be a noticeable drop in engine speed and a drop in slip speed to below 100 RPM. If the TCC apply can not be detected:
    • Refer to the Shift Speed table for the correct apply speeds.
    • Lightly tap and release the brake pedal. The TCC will release on most applications.

Part Throttle Detent Downshift

  1. Place the gear selector in the OVERDRIVE position.
  2. Accelerate the vehicle to 64–88 km/h (40–55 mph) in FOURTH gear.
  3. Quickly increase throttle angle to greater than 50 percent.
  4. Verify the following:
    • The TCC releases
    • The transmission downshifts immediately to THIRD gear

Full Throttle Detent Downshift

  1. Place the gear selector in the OVERDRIVE position.
  2. Accelerate the vehicle to speeds of 64–88 km/h (40–55 mph) in FOURTH gear.
  3. Quickly increase throttle angle to 100 percent (WOT).
  4. Verify the following:
    • The TCC releases
    • The transmission downshifts immediately to SECOND gear

Manual Downshifts

The shift solenoid valves do not control the initial downshift for the 4–3 or the 3–2 manual downshifts. The 4–3 and the 3–2 manual downshifts are hydraulic. The 2–1 manual downshift is electronic. The solenoid states should change during or shortly after a manual downshift is selected.

Manual 4–3 Downshift

  1. Place the gear selector in the OVERDRIVE position.
  2. Accelerate the vehicle to 64–88 km/h (40–55 mph) in FOURTH gear.
  3. Release the throttle while moving the gear selector to THIRD.
  4. Verify the following:
    • The TCC releases
    • The transmission downshifts immediately to THIRD gear
    • The engine slows the vehicle

Manual 4–2 Downshift

  1. Place the gear selector in the OVERDRIVE position.
  2. Accelerate the vehicle to 64–72 km/h (40–45 mph).
  3. Release the throttle while moving the gear selector to SECOND.
  4. Verify the following:
    • The TCC releases
    • The transmission downshifts immediately to SECOND gear
    • The engine slows the vehicle

Manual 4–1 Downshift

  1. Place the gear selector in the OVERDRIVE position.
  2. Accelerate the vehicle to 48 km/h (30 mph).
  3. Release the throttle while moving the gear selector to FIRST.
  4. Verify the following:
    • The TCC releases.
    • The transmission downshifts immediately to FIRST gear.
    • The engine slows the vehicle.

Coasting Downshifts

  1. Place the gear selector in the OVERDRIVE position.
  2. Accelerate the vehicle to FOURTH gear with the TCC applied.
  3. Release the throttle and lightly apply the brakes.
  4. Verify the following:
    • The TCC releases
    • Downshifts occur at speeds shown in the Shift Speed table. Refer to Shift Speed.

Manual Gear Range Selection

The shift solenoids control the upshifts in the manual gear ranges.

Perform the following tests using 10 to 15 percent throttle angle.

Reverse

  1. With the vehicle stopped, move the gear selector to REVERSE.
  2. Slowly accelerate the vehicle.
  3. Verify that there is no noticeable slip, noise or vibration.

Manual First

  1. With the vehicle stopped, move the gear selector to FIRST.
  2. Accelerate the vehicle to 32 km/h (20 mph).
  3. Verify the following:
    • No upshifts occur
    • The TCC does not apply
    • There is no noticeable slip, noise, or vibration

Manual Second

  1. With the vehicle stopped, move the gear selector to SECOND.
  2. Accelerate the vehicle to 57 km/h (35 mph).
  3. Verify the following:
    • The 1–2 shift occurs
    • The 2–3 shift does not occur
    • There is no noticeable slip, noise or vibration

Manual Third

  1. With the vehicle stopped, move the gear selector to THIRD.
  2. Accelerate the vehicle to 64 km/h (40 mph).
  3. Verify the following:
    • The 1–2 shift occurs
    • The 2–3 shift occurs
    • There is no noticeable slip, noise or vibration

The shift length may be a bit long until a few drive cycles.

Customer: replied 4 months ago.
thanks
Expert:  Ryan Schott replied 4 months ago.

no problem let me know how it goes

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