Have Questions?
Professional-grade parts used trackside.
Expert help during business hours.
Encrypted checkout & trusted payments.
Orders ship quickly from regional warehouses.
The Walker SoundFX® 18138 universal muffler is engineered for durability, OE-style sound quality, and versatile installation across a wide range of GM trucks from the mid-1990s through the mid-2000s. Constructed with aluminized steel for corrosion resistance and designed with mechanical joints that withstand thermal expansion, this muffler delivers long-lasting reliability and smooth exhaust tone.
Its large-capacity oval design with a 2.75-inch offset inlet and 2.75-inch offset outlet supports high-flow V6 and V8 applications, making it ideal for both stock replacement and custom exhaust configurations.
Aluminized steel construction improves corrosion resistance and longevity
Internal drainage system reduces moisture buildup
Louvered tube internal design maintains OE-style sound quality
Mechanical joints & spun-locked heads resist warping under heat cycles
Universal-fit configuration with expandable bushings for flexible adaptation
Designed & tested for dependable acoustic performance
| Specification | Value |
|---|---|
| Shape | Oval |
| Finish | Aluminized |
| Inlet Type | Pipe Connection |
| Outlet Type | Pipe Connection |
| Inlet Inside Diameter | 2.750 in |
| Outlet Outside Diameter | 2.750 in |
| Body Height | 7.000 in |
| Body Length | 24.000 in |
| Body Width | 9.000 in |
| Overall Length | 29.000 in |
| Inlet Location | Offset |
| Outlet Location | Offset |
| Inlet Quantity | 1 |
| Outlet Quantity | 1 |
| Hanger Included | No |
| Reversible | No |
| Fitment Type | Universal |
| Body Material | Steel |
| Grade Type | Premium |
| Part Description | SoundFX Universal Muffler |
| Inlet Offset | 2.625 in |
(Universal part — below are known applications where this muffler fits or can be adapted)
C1500 (1994–1999) — 4.3L, 5.0L, 5.7L, 6.5L
C2500 (1993–2000) — 4.3L, 5.0L, 5.7L, 6.5L
C3500 (1993–2000) — 6.5L
K1500 (1994–1999) — 4.3L, 5.0L, 5.7L, 6.5L
K2500 (1993–2000) — 4.3L, 5.0L, 5.7L, 6.5L
K3500 (1993–2000) — 6.5L
Silverado 1500 (1999–2006) — 4.3L, 4.8L, 5.3L
Silverado 1500 Classic (2007) — 4.3L, 4.8L, 5.3L
C1500 (1994–1999) — 4.3L, 5.0L, 5.7L, 6.5L
C2500 (1993–2000) — 4.3L, 5.0L, 5.7L, 6.5L
C3500 (1993–2000) — 6.5L
K1500 (1994–1999) — 4.3L, 5.0L, 5.7L, 6.5L
K2500 (1993–2000) — 4.3L, 5.0L, 5.7L, 6.5L
K3500 (1993–2000) — 6.5L
Sierra 1500 (1999–2006) — 4.3L, 4.8L, 5.3L
Sierra 1500 Classic (2007) — 4.3L, 4.8L, 5.3L
Universal muffler — requires cutting, fabrication, and welding for correct fit
Check existing exhaust tube diameter for compatibility with the 2.75" inlet/outlet
Hangers not included — installer must reuse or fabricate mounting supports
Maintain proper clearances from heat-sensitive components
Confirm flow direction based on offset inlet and outlet orientation
Recommended for custom systems or replacement of stock GM truck mufflers
Professional installation is strongly recommended due to universal design
May require reducers or adapters depending on factory pipe size
Order Processing
All orders are processed and shipped within 24 hours of purchase (excluding weekends and holidays).
Orders placed after 3:00 PM EST may ship the following business day.
Shipping Methods
Customers select their preferred shipping method and speed at checkout.
Shipping times are determined by the carrier and cannot be guaranteed by us.
Tracking information will be provided once your order has shipped.
Shipping Coverage
If your package arrives damaged, please notify the delivery driver immediately and contact the shipping carrier to file a claim.
You must report any missing or damaged items within 14 days of delivery.
After this time, we cannot be held responsible for lost or damaged items.
Return Window
You have 30 days from the date of delivery to request a return.
After 30 days, we are unable to accept returns, exchanges, or refund requests.
Eligibility
Items must be returned in their original condition—unused, unwashed, and with all tags and packaging intact.
Certain products may not be eligible for return (e.g., special-order items, customized products, or perishable goods).
Items that have been altered, installed, or modified cannot be returned.
Return Process
Contact our Customer Support team to request a Return Authorization (RMA) before sending items back.
Once your return is approved, you’ll receive instructions on where to send the product.
Customers are responsible for return shipping costs unless the item was defective or incorrect.
Refunds
Refunds are issued to the original payment method once the returned item has been received and inspected.
Please allow 5–10 business days for the refund to appear on your account.
In some cases, a restocking fee may apply (if applicable, this will be disclosed during your return authorization).
