Transmission and drivelineModel years not statedTrade technical source
4L60-E burnt 3-4 clutch pack
GM 4L60/E family of transmissions (no model years stated)
FaultCrate・4L60-E burnt 3-4 clutch pack
Low line pressure and/or leaks of 3rd gear oil are the root cause of most 3-4 slipping.
Small leaks at several points in the circuit can add up to enough pressure loss to allow slipping.
The weak OE 3-4 backing plate flexes during application, letting heat build up unevenly in the clutch pack.
The TCC valve bore is a high-wear area that leaks 3-4 oil via the 2nd clutch circuit.
A screen commonly fills with debris, causing a pressure drop in supply to EPC which results in low line pressure.
Malfunctions of the TP, MAP and MAF sensors can negatively affect line pressure control.
What to do
- Test the 3rd accumulator checkball capsule for leakage; a leaking capsule is a leading cause of 3-4 clutch failure.
- Whenever a burnt clutch pack is found, inspect all three circuits methodically to find and eliminate all leaks.
- Thicker heavy-duty backing plates that eliminate clutch pack flex are available in the aftermarket.
Caution
- An obvious leak such as a cracked apply piston should not stop further investigation.
- Replacing the 3rd accumulator ball with a cup plug often results in soft 2-3 shifts and 3-2 flares.
Applies to
- Burnt 3-4 clutch packs are notoriously common in the GM 4L60/E family of transmissions.
See the evidence (1 documents, 12 passages)
| Document | Publisher | Date |
|---|---|---|
| [1]All Over the Map: Attacking 4L60/E Burnt 3-4 Clutches with Confidence ↗ | Trade technical sourceSonnax | 2018-06-06 |
Applies toBurnt 3-4 clutch packs are notoriously common in the GM 4L60/E family of transmissions.
Burnt 3-4 clutch packs are notoriously common in the GM 4L60/E family of transmissions.— [1]
Why it happensLow line pressure and/or leaks of 3rd gear oil are the root cause of most 3-4 slipping.
Low line pressure and/or leaks of 3rd Gear oil are the root cause of most 3-4 slipping.— [1]
Why it happensSmall leaks at several points in the circuit can add up to enough pressure loss to allow slipping.
even small leaks at a few junctions along the way can add up to a big enough pressure loss to allow slipping.— [1]
Why it happensThe weak OE 3-4 backing plate flexes during application, letting heat build up unevenly in the clutch pack.
The weak OE 3-4 backing plate flexes during application, allowing heat to build up unevenly within the clutch pack’s limited space.— [1]
Why it happensThe TCC valve bore is a high-wear area that leaks 3-4 oil via the 2nd clutch circuit.
Even without blocking the TCC valve open, its bore is a high-wear area that leaks 3-4 oil via the 2nd clutch circuit.— [1]
Why it happensA screen commonly fills with debris, causing a pressure drop in supply to EPC which results in low line pressure.
This screen commonly fills with debris, causing a pressure drop in supply to EPC which results in low line pressure— [1]
Why it happensMalfunctions of the TP, MAP and MAF sensors can negatively affect line pressure control.
malfunctions with TP, MAP and MAF sensors can all negatively affect line pressure control.— [1]
How to confirmTest the 3rd accumulator checkball capsule for leakage; a leaking capsule is a leading cause of 3-4 clutch failure.
always vacuum or wet air test the 3rd accumulator checkball capsule for leakage, as a leaking capsule is a leading cause of 3-4 clutch failure.— [1]
How to confirmWhenever a burnt clutch pack is found, inspect all three circuits methodically to find and eliminate all leaks.
Any time a burnt clutch pack is found, all three circuits must be inspected methodically to discover and eliminate all the leaks— [1]
CautionAn obvious leak such as a cracked apply piston should not stop further investigation.
The presence of an obvious leak, such as a cracked apply piston, should not stop you from investigating further.— [1]
CautionReplacing the 3rd accumulator ball with a cup plug often results in soft 2-3 shifts and 3-2 flares.
Replacing the 3rd accumulator ball with a cup plug often results in soft 2-3 shifts and 3-2 flares due to arrested venting.— [1]
RepairThicker heavy-duty backing plates that eliminate clutch pack flex are available in the aftermarket.
Thicker, heavy-duty backing plates that completely eliminate clutch pack flex are available in the aftermarket.— [1]
Put together by FaultCrate from public records and technical documents. The cause and the repair are for the workshop to decide with the vehicle in front of it. Counts are records, not failure rates.
List the records (1 that can be opened)
Records whose recall number, document number or text matches. Each line says why it matched.
- Investigation of 2-4 Band or 3-4 Clutch Damage on Automatic TransmissionManufacturer communication 2001-06-28・text contains "3-4 CLUTCH"