4L70E Banner Rebuild Kit 2004

If you are rebuilding the automatic out of a 2004 Silverado, Sierra, Tahoe, Yukon, Suburban, Avalanche, Express or Trailblazer because it flares between 2nd and 3rd, slips in 4th or engages late on a cold morning, this banner kit is built for that job. It is a new soft-parts kit for a 2004 unit in GM's 4L60E family, listed under the 4L70E name because the 4L60E, 4L65E and 4L70E share the same internal design and are catalogued together.

A note on the name: what a 2004 truck actually has

No vehicle left the factory with a 4L70E in 2004. ATRA's 2005 GM update spells out the timeline: the input speed sensor (ISS) hardware was pulled into some mid-2005 units, fully implemented for 2006, and the 4L70E itself was introduced for 2006 as the ISS-equipped member of the family. A 2004 truck therefore has a 4L60E (RPO M30) or, behind the bigger V8s, a 4L65E (RPO M32). The soft parts that wear out in those units are the same pieces this kit renews, which is why the year matters more than the badge. Our 4L60E, 4L65E and 4L70E interchange guide walks through what changed from year to year.

What the banner kit does in a 4L70E-family transmission

A banner kit is the middle step between a plain gasket set and a full master kit. It pairs the overhaul set (the gaskets, piston seals, O-rings and sealing rings that hold apply pressure inside each drum) with new friction plates for the clutch packs. In this transmission the forward, overrun, 3-4, coast and reverse input clutches all rely on rubber piston seals and on the sealing rings that carry oil from the pump and input shaft into the rotating drums. After a couple of hundred thousand miles those seals harden, apply pressure leaks away, and the frictions slip and glaze. Renewing both at once restores clamping force without paying for hard parts that are still good.

Symptoms that point to a banner kit rebuild

• A flare or slip on the 2-3 shift, then loss of 3rd and 4th: the burnt 3-4 clutch pack this family is known for
• Slow engagement into Drive or Reverse when cold that improves once the fluid warms, a sign of hardened piston seals
• Dark, burnt-smelling fluid and friction lining packed on the pan magnet
• Slipping in 2nd and 4th together, which points at the 2-4 band and servo rather than a clutch pack

How to confirm it before you buy

Drop the pan before you commit to a rebuild. A filter loaded with friction material and a sludgy magnet confirms internal wear. If the fluid is clean but engagement is slow, work through our delayed engagement guide first, because a sticking pressure regulator or a worn pump can feel identical. Sonnax's research on burnt 3-4 clutches traces most failures to oil leaking out of the 3rd gear circuit, so read our 3-4 clutch failure guide and air-check the input housing during the rebuild. New frictions in a leaking housing burn again.

Fitment

This listing is for 2004 4L60E and 4L65E units. 2004 is a changeover year for the pump-to-case seal: most units use the wedge-style seal of the later cases, but some early-2004 transmissions still carry the round O-ring of the 1992-2003 design. Look at the seal on your pump before you order, and if it is the round style, the 1992-2003 banner kit is the safer match. For a 2005-up truck, the 2004-2014 banner kit covers the later units. Read the RPO code on the glovebox label and the ID tag on the case, or send us your year and VIN and we will confirm. More parts for this family are on the 4L70E collection page.

Install notes

• Soak new frictions in fresh fluid before assembly and measure every pack clearance with the steels you are reusing. Replace any steel that is blued or warped.
• Inspect the reaction sun shell for cracked or stripped splines while the gear train is out; a replacement sun shell is cheap insurance on a high-mileage unit.
• Set input shaft endplay before the pan goes on, and replace worn bushings while the case is empty.
• A tired EPC solenoid is a common reason the old clutches burned. If yours reads out of spec, add a pressure control solenoid to the order.
• Fill with DEXRON-VI, which GM accepts in older DEXRON-III units, check the level hot in Park with the engine running, and clear shift adapts before the road test.

Will this kit fit my 2004 4L60E even though it says 4L70E?

Yes, that is who it is for. The 4L70E name only arrived in 2006, so a 2004 truck has a 4L60E or 4L65E. The kit is listed under the 4L70E family name because these units share their seals and clutch layout. Match the pump-to-case seal style and confirm with your RPO code or VIN.

What is the difference between a banner kit and a master kit?

A banner kit renews the gaskets, seals and friction plates. A master kit usually adds more of the hard wear items such as steels, bushings, a band or a filter. If the drums, bushings and band look good at teardown, the banner kit covers the job for less money.

My truck slips from 2nd to 3rd. Will new frictions fix it?

Only if you also fix the reason the 3-4 pack burned. Sonnax traces most burnt 3-4 clutches to a 3rd gear circuit leak, so air-check the input housing, inspect the sealing rings and test line pressure during the rebuild.

Which fluid should I use after the rebuild?

Use DEXRON-VI. It is the current GM fluid and is approved for older GM transmissions that originally called for DEXRON-III. Set the final level hot, in Park, with the engine running.

Do I need to relearn shifts after rebuilding?

Yes. Clear the transmission adaptive values with a scan tool after the rebuild, then drive with light, steady throttle through all gears so the controller relearns shift timing on the new clutches.

• 4L70E 3-4 Clutch Failure: Symptoms and Fix
• 4L70E Delayed Engagement: Causes, Diagnosis and the Fix That Holds
• 4L60E, 4L65E and 4L70E: What Interchanges and What Doesn't
• 4L70E Common Problems and Fixes