2010 GMC YUKON XL 2500

Typical onset: 80,000-150,000 mi

Symptoms: Loud ticking or tapping from engine on cold start that may disappear when warm, Check Engine Light with P0300-P0308 misfire codes or P0521 oil pressure codes, Rough idle, loss of power, dead miss on one or more cylinders, Metal shavings in oil, low oil pressure at idle

Fix: AFM lifters fail due to oil starvation and weak springs, wiping out the camshaft lobes. Proper fix requires AFM delete kit, new camshaft, all lifters, timing chain, and often head gaskets if not caught early. Some shops just replace lifters and cam, others do a full top-end refresh. Budget 20-30 shop hours for thorough job with AFM delete. If it grenades a cylinder (broken valve spring or dropped valve), you're looking at engine rebuild or replacement.

Estimated cost: $3,500-6,500

Typical onset: 100,000-180,000 mi

Symptoms: Puddle of transmission fluid under truck, often near radiator, Transmission slipping, delayed engagement, or milky pink fluid (coolant cross-contamination), Trans overheating, burnt smell, harsh shifts, Visible fluid seepage at radiator inlet/outlet tanks

Fix: Steel transmission cooler lines rust through at fittings or along frame rails. The factory radiator also has an internal trans cooler that can rupture, mixing coolant and ATF — this kills the transmission fast. External line replacement is 2-3 hours labor. Internal cooler leak requires radiator replacement AND full trans flush or rebuild depending on contamination. Many techs install an external auxiliary cooler as insurance. If coolant got into trans, expect full rebuild.

Estimated cost: $400-800 (lines only), $2,500-5,000 (if trans contaminated)

Typical onset: 90,000-140,000 mi

Symptoms: Clunk or bang when shifting from Park to Drive or Reverse, Vibration at idle in gear, smooths out in Park/Neutral, Visible sagging or torn rubber on crossmember mount, Drivetrain movement visible when revving in gear with parking brake set

Fix: The rubber transmission crossmember mount fatigues from the weight of the 4L80E and constant torque cycling, especially if used for towing. Replacement is straightforward: support trans with jack, unbolt crossmember, swap mount. 1.5-2 hours labor. OEM mounts last longer than aftermarket.

Estimated cost: $250-450

Typical onset: 120,000-180,000 mi

Symptoms: Hard starting, extended crank time especially when hot, Loss of power under acceleration or at highway speed, Engine stumble, hesitation, or stalling, Whining noise from fuel tank area

Fix: The in-tank fuel pump wears out, and the inline fuel filter (mounted on frame rail) clogs if fuel quality has been poor. Filter replacement is easy — 0.5 hours. Fuel pump requires dropping the tank or cutting an access hole in the bed floor (some techs do this, not factory-approved but saves hours). Pump job is 3-4 hours book time dropping tank properly. Always replace filter with pump.

Estimated cost: $150-250 (filter only), $800-1,200 (pump + filter)

Typical onset: 150,000-220,000 mi

Symptoms: Excessive oil consumption (1 quart per 500-1,000 miles), Blue smoke on startup or under hard acceleration, Fouled spark plugs, misfires on multiple cylinders, Low compression readings across cylinders

Fix: High-mileage 6.0L engines can burn oil due to ring wear, often exacerbated by AFM lifter debris circulating in oil. If caught before scoring cylinders, a re-ring job with honing is possible (20-25 hours labor). If cylinder walls are scored or out-of-round, you need a full rebuild with bore/hone or short block replacement (30-40 hours). Many owners opt for a reman long block or used engine swap at this point.

Estimated cost: $4,000-7,000 (re-ring), $6,500-10,000 (rebuild or reman)

Symptoms: No-start condition, engine cranks but won't fire, Intermittent stalling while driving, especially when hot, Check Engine Light with P0335 or P0336 codes, Tachometer drops to zero while driving

Fix: The crank sensor behind the starter fails due to heat cycling. It's a common no-start culprit and cheap part, but labor is annoying — must remove starter to access sensor on back of block. 1.5-2 hours labor. Always use AC Delco sensor; cheap aftermarket versions fail quickly.

Estimated cost: $250-400