Hardened Forged Steel Rear Suspension Trunnion Shaft 97 mm with Precision Drilling for ISUZU Balance Shaft

The Rear Suspension Trunnion Shaft with OEM numbers 1-51381025-0 and 1513810250 is a verified direct-fit replacement for ISUZU CXK / CXZ / CXZ51K / CYZ51 / CYZ51K heavy-duty trucks equipped with 6WF1 / 10PE1 diesel engines. This trunnion shaft is the core load-bearing and pivoting component of the rear suspension system, connecting the rear suspension swing arm to the chassis frame while allowing the arm to pivot about the shaft axis under heavy loads and challenging road conditions.

The rear suspension trunnion shaft is a critical pivot element in the rear suspension system of heavy-duty trucks. It is mounted in the trunnion shaft bracket on the chassis frame and connects to the suspension swing arm through a bronze bushing. When the vehicle travels over uneven road surfaces, the suspension swing arm pivots about the trunnion shaft axis, absorbing road impacts and maintaining tire contact with the ground. The shaft must simultaneously withstand vertical loads (vehicle and cargo weight), torsional moments, and lateral forces.

The 6WF1 is a 14.3L inline-six turbo-diesel engine producing 330–370 PS, used from 1999 to 2007. The 10PE1 is a 15.7L inline-six diesel engine. The trunnion shaft is manufactured from hardened forged steel with precision drilling to ensure excellent strength, wear resistance, and dimensional stability under high-load conditions.

Replace the trunnion shaft when any of these symptoms appear:

• Abnormal noise or metallic clunking from the rear suspension — excessive clearance between the shaft and bushing causes metal-to-metal contact.
• Vehicle pulling to one side or abnormal rear axle alignment — worn or bent trunnion shaft causes suspension geometry deviation.
• Suspension swing arm binds or fails to pivot smoothly — worn or corroded shaft surface prevents smooth arm movement.
• Visible wear grooves or deformation on the shaft — long-term high-load operation causes journal wear or bending.
• Abnormal bushing wear or burning — increased shaft surface roughness accelerates bushing wear.
• Reduced vehicle driving stability — a failed trunnion shaft prevents the rear suspension from effectively absorbing road impacts.

1. Preparation: Raise the vehicle on a hoist. Support the rear axle and suspension swing arm. Relieve suspension system tension.
2. Removal: Remove the trunnion shaft bracket mounting bolts. Remove the trunnion shaft bracket and shaft. Inspect the shaft journal for wear.
3. Inspection: Inspect the trunnion shaft for wear grooves, bending, or cracks. Measure the journal diameter and compare to specification. Inspect the trunnion shaft bushings and bracket for wear or deformation.
4. Installation: Apply appropriate grease to the trunnion shaft journal surface. Install the trunnion shaft into the bracket. Install the bracket and torque the mounting bolts to specification.
5. Final Check: Verify the suspension swing arm pivots smoothly without binding. Confirm all fasteners are torqued to specification.
6. Road Test: Lower the vehicle and perform a road test to verify proper rear suspension operation and absence of abnormal noise.

• Every 10,000 km: Inspect trunnion shaft journal for wear. Check suspension swing arm pivoting for smoothness.
• Every 40,000–50,000 km: Inspect trunnion shaft bushings for wear. Check shaft for bending or deformation.
• Every 100,000 km: Perform magnetic particle inspection (MT) on the trunnion shaft. Replace worn bushings and bracket.
• When abnormal rear suspension noise or pulling is detected: Inspect trunnion shaft and bushings immediately.
• At any rear suspension service: Always inspect the trunnion shaft and replace if any abnormality is found.

• Standard Packaging: Anti-rust oil + VCI film + neutral carton.
• Custom Packaging: Neutral box, color box, or customer-branded packaging.
• Suitable For: Heavy-truck suspension repair shops, ISUZU parts distributors, fleet maintenance centers.
• Supply Capacity: Stable batch supply with batch-level quality reports available.
• MOQ: Small quantities accepted (quantity discounts available).