6L90 Reaction Shell 2007, used and ready to install. Fits the 6L90. Ships fast from the USA.
This listing is a bare, used OEM case for the GM 6L90, not a reaction shell. It is the 4x4 version of the case, casting number 24259565, for 2007-and-up units, and it is sold empty: no internal parts are included. Rebuilders and owners usually land here after a failure that went past the clutches, such as a broken part that punched or cracked the case, a stripped bolt boss, or a worn bore that cannot be saved. If your 2007-2014 Silverado or Sierra 2500HD/3500HD 4x4 has a core that is otherwise rebuildable, a good used case is far cheaper than a complete transmission.
Everything in the 6L90 hangs off this casting. The converter housing and pump bolt to the front face, the extension or transfer case adapter bolts to the rear, and the valve body and TEHCM mount underneath behind the pan. Inside, the case carries the clutch packs and the rear geartrain, and it is the stationary member the low/reverse clutch and low sprag push against to hold the output carrier in first and Reverse. The 6L90 is GM's strengthened, heavy-duty version of the 6L80, and ATSG documents that the two cases are different lengths, along with the park rod, park pawl and pan, because the 6L90 carries taller clutch housings and an extra 4-5-6 friction. A 6L80 case is not a substitute. This one measures 17-3/4 inches from the bell face to the extension housing face and uses an 18-bolt pan.
Clean the old case and inspect it under good light before condemning it; many leaks blamed on the case are a cooler line fitting, pan gasket or a cracked converter housing instead. Check the clutch spline lugs for notching and the bolt holes with a thread gauge. If the transmission failed hard, find out why first, because the cause will destroy a new case just as fast. Our 6L90 common problems guide covers the drum weld cracks, pump issues and clutch failures that most often lead to a teardown, and the Silverado 2500 6L90 problems guide lists the truck-specific failures to rule out.
This is the 4x4 case for the 6L90 (RPO MYD), 2007 and later, cast number 24259565. In the GMT900 trucks that means the 2007-2014 Silverado and Sierra 2500HD/3500HD with four-wheel drive. Two-wheel-drive units use a different case, so do not order this for a 2WD truck. Compare the cast number on your old case, confirm the pan uses 18 bolts and measure bell face to extension face, or send us your year and VIN and we will confirm. For the rest of the hardware, browse the 6L90 parts page.
| Fits | 6L90 2007 |
| Part type | Reaction Shell |
| Condition | Used |
| Brand | OEM |
| Ships | From the USA |
| Warranty | 1-year |
No. Despite the page title, this item is a bare used 6L90 transmission case, cast number 24259565, for 4x4 units. No internal parts are included.
No. This is the 4x4 case. Two-wheel-drive 6L90 units use a different case, so match the cast number on your old case or send us your VIN.
No. The 6L90 is the heavy-duty version of the 6L80, and ATSG shows the two cases are different lengths, with different park rods, park pawls and pans, so they do not interchange.
Plan on transferring the manual shaft and park parts, cooler fittings and plugs, then rebuilding with a full overhaul kit, inspected or new drums, and a good pump. Replace every seal on the parts you transfer.
Dexron VI. GM lists a 6.0-quart fluid change capacity for the 6L90; a rebuilt unit needs more to fill the converter and cooler, so set the level hot with the engine running.
