DIAGNOSTIC ROADMAP
MAINTENANCE ROADMAP
Common 986 & 996 failure points, walked through symptom to root cause. Tap an issue to expand the step-by-step diagnostic.
8 DIAGNOSTICS
STEP-BY-STEP DIAGNOSTIC
- 1Pull the oil filter and cut it open — look for ferrous (magnetic) flakes. Any metal here is a red flag.
- 2With a stethoscope, listen at the bellhousing at idle. A dry, gritty rumble that rises with rpm points to the IMS bearing.
- 3Check for a slow oil weep from the rear main seal — a failing IMS often drags the seal with it.
- 4If debris or rumble is present, stop driving and book an IMS retrofit before the engine is run again.
LIKELY CAUSEThe original intermediate shaft bearing races pit and fail over time. A ceramic-hybrid retrofit bearing is the fix.
