P0894: How to Diagnose & Fix — Transmission Component Slipping
6 vehicles · 5 makes · $150-$9,000 repair
How to diagnose and fix P0894: most-reported vehicles
Ranked by owner reports. Each card gives the symptoms, how to confirm the cause, the fix, parts and sources for that vehicle.
GMC Yukon XL · 2007–2016
GMT900 and early K2XX Yukon XL models with 6L80/6L90 transmissions commonly develop leaks at the transmission cooler line crimps or quick-connect fittings. Owners report red fluid spots, low transmission fluid, and in severe cases slipping or overheating if fluid loss is significant. This issue is widely documented in owner reports, and GM safety recall 14V-152 (GM bulletin 14121) covered 2015 Yukon XL models with the 6-speed automatic whose cooler line may not be fully seated in its fitting.
Common Symptoms
- Red transmission fluid spots under front of vehicle
- Burnt ATF smell after driving
- Transmission slipping or delayed engagement
- Transmission over-temp message (if severe)
How to Fix
Replace the leaking transmission cooler line(s) or fitting seals; many repairs involve replacing the entire line assembly rather than re-crimping. After repair, verify fluid level with the correct ATF (Dexron VI for 6L80/6L90) and check for overheating-related damage.
Sources for this issue (2)
Hyundai Sonata · 2011–2019
The A6-series six-speed automatic fitted to the YF and LF Sonata wears the aluminium bores that house the solenoid pressure-reducing valves. The worn bores leak line pressure internally, so clutch apply pressure falls and the transmission either flares (RPM jumping between gears as a clutch slips) or bangs into gear once the pressure command finally builds. Reports of the wear appearing by 40,000-60,000 miles are common. Symptoms are frequently misdiagnosed as a bad solenoid pack and the solenoids replaced without addressing the bores, which returns the fault within months. This is distinct from the dry dual-clutch (DCT) shudder complaint on the 1.6L turbo Sonata Eco - the A6MF is a conventional torque-converter automatic.
Common Symptoms
- Engine RPM flares between upshifts
- Harsh or banging 1-2 and 2-3 shifts
- Delayed engagement into drive or reverse
- Slipping under light throttle
- Intermittent stuck in one gear / limp mode
- Check engine light with transmission pressure codes
How to Fix
The durable repair is a valve body rebuild with an oversized valve kit (Sonnax-style) to restore the worn bores, or a replacement valve body - roughly $600-1,400 installed, versus $2,500-4,500 for a full transmission replacement. Start by scanning for pressure-control codes and checking fluid level and condition on a warm engine; some early-stage cases improve with a proper SP-IV fluid service and a TCU relearn, but that is a delay not a cure. Have the shop specifically confirm bore wear before agreeing to a solenoid-only repair. No recall covers this; some cars were repaired under the 10-year/100,000-mile powertrain warranty for original owners.
Sources for this issue (3)
GMC Yukon XL · 2015–2024
The 8-speed (8L90) and 10-speed (10L80) automatic transmissions in the Yukon XL develop a torque converter clutch (TCC) shudder felt as a vibration or shake at light throttle between 25-80 mph. The shudder mimics driving over rumble strips. GM issued TSB 18-NA-355 (covering 2015-2017 Yukon models with the 8L90) and changed to a reformulated Mobil 1 Synthetic LV ATF HP fluid. GM attributes the shudder to moisture absorbed by the original, hygroscopic fluid.
Common Symptoms
- Vibration or shudder at 25-80 mph under light throttle
- Feels like driving over rumble strips
- Shudder disappears under heavy acceleration
- Vibration most noticeable in overdrive gears
- Intermittent — may come and go
How to Fix
First-line fix: complete transmission fluid exchange per bulletin 18-NA-355 with GM-approved Mobil 1 Synthetic LV ATF HP (blue label) — NOT the original black-label version. If shudder persists after the correct fluid exchange, further diagnosis per GM service information is needed and the torque converter may require replacement. Do NOT use aftermarket friction modifiers or additives — GM states intermixing other fluids or additives will not give satisfactory results.
Sources for this issue (2)
Chevrolet Tahoe · 1995–2010
Audi R8 · 2021–2022
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P0894 code reference
General diagnostic-code context. The code alone does not confirm a cause for your vehicle; use the applicable issue card and its sources.
Frequently asked questions
What does P0894 mean?
P0894 stands for "Transmission Component Slipping." This generic transmission code means the PCM/TCM detected that a rotating component inside the transmission is slipping, by comparing input and output speeds and finding more difference than there should be for the commanded gear. Slippage indicates clutches or bands are not holding properly, which can quickly worsen and damage the transmission through overheating and accelerated wear. It often comes with rough or flaring shifts, reduced power, and overheating, and should be addressed promptly.
What are the most common causes of P0894?
The most common causes of P0894 are: Low, dirty, or burnt transmission fluid, Worn clutch packs or bands, Faulty shift or pressure control solenoid, Internal hydraulic/valve body problems, Worn torque converter, Faulty speed sensors giving false slip readings, General internal transmission wear. The specific cause varies by vehicle.
How much does it cost to fix P0894?
Repair costs for P0894 range from $150 to $9,000, depending on the vehicle and root cause.
Which vehicles are affected by P0894?
Au7o has documented P0894 across 6 vehicle models from 5 manufacturers: Audi, Buick, Chevrolet, GMC, Hyundai.
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Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.