You put it in Drive and nothing happens. Engine runs, trans is in gear, but no forward motion. Here's what's happening.
Most common causes
Cause 1: Forward clutch failure
The most common cause of total loss of forward gears.
Symptoms: No forward motion at all, reverse works (sometimes)
Fix: Rebuild ($1,500-3,500)
Cause 2: Cracked sun shell
The famous 4L60E sun shell failure.
Symptoms: Often no reverse first, then no drive
Fix: Sonnax billet sun shell during rebuild
Read our 4L60E rebuild kit guide for HD components
Cause 3: Broken input shaft
Symptoms: Trans makes noise but no power transfer
Fix: Read our 4L60E input shaft failure guide
Cause 4: Low fluid
Symptoms: Hesitation then no engagement
Fix: Top off with Dexron VI
Cause 5: PR valve failure
Symptoms: All gears slipping, eventually no drive
Fix: Sonnax PR valve kit
Read our Sonnax PR valve install guide
Cause 6: Pump failure
Symptoms: No engagement in any gear
Fix: Pump rebuild or replacement
Read our 4L60E pump rebuild guide
Diagnostic path
Step 1: Verify fluid
Cheapest possible fix.
Step 2: Try reverse
- Reverse works = forward-specific issue (clutch or sun shell)
- Reverse doesn't work either = bigger problem
Step 3: Check codes
Read our 4L60E check engine light guide
Step 4: Pressure test
If pressure is OK but no drive: internal failure
If pressure is low: pump or PR valve
Step 5: Pan inspection
Wear material reveals what failed
When it's catastrophic
Major rebuild needed if:
- Metal flakes in pan
- Pieces of plastic/sun shell in pan
- Burnt fluid
- High mileage with no service history
Read our 4L60E rebuild cost guide
Need 4L60E rebuild parts? Shop our 4L60E catalog. Master rebuild kits, Sonnax sun shells, HD components. Free shipping over $70.
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