6L90 Reaction Shell 2006, remanufactured and ready to install. Fits the 6L90. Ships fast from the USA.
This page is titled reaction shell, but the part is a rebuilt heavy-duty input planetary carrier with its sun gear for the GM 6L90. It is the six-pinion front gearset with 22-tooth pinions and a 4.480 inch outside diameter, listed for 2006-and-up units. Shoppers usually reach it after a teardown on a Silverado or Sierra 2500HD/3500HD, an Express or Savana van, or a towing Suburban turned up a noisy or chewed-up front planet, or when a 6L80 builder wants the stronger 6L90 gearset.
The 6L family uses a Lepelletier layout: a simple planetary at the front feeding a Ravigneaux compound set at the rear. The front set is the input planet. Turbine torque enters it and it delivers a reduced speed to the clutches that need it, so it is loaded in most forward gears and in Reverse. GM built the 6L90 to carry more torque than the 6L80, and one of the key changes was this gearset: the 6L90 input planet carries two extra pinion gears, six in total, which spreads the load over more teeth and bearings. That is why the heavy-duty trucks and vans got it, and why this carrier is the one to use when the original has worn pinions or a damaged sun gear.
Gear noise is easy to confuse with pump, converter or rear end noise. Note whether the sound follows engine speed or road speed, and whether it changes in Neutral at the same rpm. A noise present in Park and Neutral that follows engine rpm is more likely the converter or the pump; our 6L90 pump failure guide covers that side. Once the unit is apart, check each pinion for end play and rough rotation and inspect the sun gear teeth. The 6L90 common problems guide lists the other failures to rule out before you order hard parts.
This carrier is for the GM 6L90 (RPO MYD), listed as 2006-and-up. The 6L90 itself went into production in the 2007 model-year heavy-duty trucks, so treat 2006 as the start of the shared 6L80/6L90 design rather than a separate 2006 version. It is also used as a strength upgrade in 6L80 builds; the 6L80 front set has four pinions. ATSG warns that fifteen 6L80 and 6L90 internal parts differ in height, diameter or thickness, so match this carrier against your original, including the 4.480 inch OD and the 22-tooth pinions, before assembly. If you are unsure, send us your year and VIN. More parts are on the 6L90 parts page.
| Fits | 6L90 2006 |
| Part type | Reaction Shell |
| Condition | Remanufactured |
| Brand | OEM |
| Ships | From the USA |
| Warranty | 1-year |
No. It is a rebuilt heavy-duty 6L90 input planetary carrier with its sun gear, six pinions with 22 teeth, 4.480 inch outside diameter.
It is commonly used to upgrade a 6L80, whose front set has four pinions. Many 6L80 and 6L90 parts differ in size, so match the OD and the mating ring gear before you commit.
The listing uses 2006-up because the 6L80 and 6L90 share a design that began in 2006. In practice the carrier fits 6L90 units from their 2007 start onward.
Replace the frictions, steels, seals and thrust washers, inspect the ring gear and bearings, and flush the cooler and lines before the rebuilt unit goes back in.
Dexron VI. Set the level hot with the engine running, then reset the transmission adapts so shifts relearn on the rebuilt unit.
