StreetMonster Chevy 4L65E Transmission & Converter Conversion Package

In-stock transmissions usually ship the next business day.

Custom builds or out-of-stock units typically ship within 2–4 weeks.

Need it sooner? Call us — we can often make special arrangements.

We offer the most comprehensive coverage in the industry:

• StockMonster: 1 Year (Extendable to 4 Years with Extend)
• StreetMonster: 2 Years (Extendable to 5 Years with Extend)
• SportMonster: 3 Years (Extendable to 6 Years with Extend)
• TrackMonster: 1 Year (Extendable to 4 Years with Extend)

Extend warranties are optional add-ons available during checkout.

No — we offer a $299 Flat-Rate One-Way Shipping to any address, commercial or residential.

If you find a better rate, you're welcome to arrange your own shipping.

The easiest way to tell the difference is by checking your vehicle’s year and engine type:

• In 1998, GM introduced the LS1 engine and began using the 4L65.
• By 1999, trucks with 4.8L, 5.3L, or 6.0L LS engines came factory-equipped with the 4L65.
• If your vehicle is 1998 or older and does not have an LS engine, it likely has a 4L60.

Tip: If your vehicle is from 1999+ and has an LS engine, use our 4L65 transmission for proper fitment.

Yes! Our upgraded 4L65 builds are ideal for cammed and even boosted LS-powered vehicles.

• For moderate cams and street use, choose our StreetMonster 4L65 with a stall converter.
• For setups making 450 HP or more, upgrade to our SportMonster or TrackMonster for maximum reliability and performance.

All units are dyno-tested.

Yes — the 4L65 is a stronger version of the 4L60E from the factory.

• It features upgraded internal components including the input shaft, planetaries, and sun shell.
• Designed specifically for LS-based applications and trucks from 1999+.
• Our upgraded versions can handle over 600 HP, with the TrackMonster 4L65 rated for 1000 HP.

While both can be built strong, the 4L65 is the better platform for high-output LS builds.

No reflash or tuning is required for 4L60 or 4L65 replacements in factory applications.

• Simply disconnect the battery during install and clear all DTC/fault codes before driving.
• The vehicle’s PCM will relearn shift strategy automatically.
• We include a full step-by-step guide in our Installation Manual

Proper code clearing and Installation is key to smooth operation and long-term performance.

No — fluid must be purchased separately. We offer special discounted prices and even cheaper shipping options when you bundle with our fluid at checkout.

Returning your core is simple. Once you are ready to return your core, you can initiate the return process in one of two ways:

• Fill out our Core Return Form (available online) using the button below.
• Or call our Customer Service Team at 800-708-0087 to schedule your return freight pickup.

Please Note:

• The customer is responsible for the return shipping cost.
• A flat-rate fee of $299 will be deducted from your core refund to cover return freight and handling. If Round Trip Shipping is not Prepaid Upfront.
• The core must be the same model and not cracked or damaged beyond rebuild.

Our goal is to make this process as seamless as possible — if you have questions about your core return, just give us a call.