6L90 Sun Shell 2006, used and ready to install. Fits the 6L90. Ships fast from the USA.
A heavy-duty GM truck or van that will not back up, or that skips gears after a rebuild, often turns out to have a damaged sun shell in the rear of the 6L90. This used OEM shell is the lower-cost route when you are already rebuilding the transmission and want a factory part rather than paying for a remanufactured one. Below is what the part does, how to tell if yours is finished, and how to make sure this one matches before it goes in.
Like the ZF design it is based on, the 6L90 pairs a simple front planetary with a Ravigneaux rear set. The rear set uses a large reverse sun gear and a small forward sun gear working through the same long and short pinions. The sun shell connects the large sun to the outside world: the 3-5-R clutch turns it to make third, fifth and Reverse, and the 2-6 clutch locks it to make second and sixth. Because so much depends on it, a shell with worn splines or a cracked weld does not fail quietly. It usually takes several gears with it.
No Reverse on these units is common, and much of the time the cause is hydraulic or electrical. Sonnax lists a misplaced number 5 checkball, the wrong separator plate or gaskets, a stuck 3-5-R clutch regulator valve and TEHCM solenoid faults ahead of hard part failures. Our 6L90 valve body testing guide shows how to separate those from mechanical damage. If the valve body checks out and the pan is full of steel, pull the unit and inspect the shell splines, the sun gear teeth and the welds.
This shell is listed for 2006. The 6L family launched with the 6L80 in 2006, and the 6L90 itself first appeared in 2007 model year trucks, so treat the year here as a catalog label and fit by the part, not the date. Applications include the 2007-2014 Silverado and Sierra 2500HD/3500HD with the 6.0L, the 2008-2019 Suburban 2500 and the Express and Savana 2500/3500 vans from 2010. Lay your old shell next to the listing photo and match spline count, shaft length and overall height. Do not try a 6L80 shell in a 6L90 or the other way round; the 6L90 case is longer and its gearsets are heavier. If you are unsure, send us your year and VIN, and browse the rest of the 6L90 parts collection.
Use new frictions, steels and seals from the 6L90 overhaul kit, replace the disturbed thrust washers and bearings, and set end play to spec. GM now supplies the 6L90 filter (24236517) and seal (24225347) as separate parts, so order both. Flush the cooler, fill with DEXRON-VI, check the level hot at the fill plug and reset adapts. For a broader look at what fails on these units, see 6L90 common problems.
| Fits | 6L90 2006 |
| Part type | Sun Shell |
| Condition | Used |
| Brand | OEM |
| Ships | From the USA |
| Warranty | 1-year |
Doing this repair right usually means replacing these at the same time. Same transmission, ships together.
The 6L90 first appeared in 2007 model year trucks; 2006 was the launch year of the 6L80. Fit this shell by matching it to your part and VIN, not by the year in the title.
It is a used OEM part. Clean and inspect splines, welds and gear teeth before you install it, as you would any hard part in a rebuild.
It can. The 2-6 clutch holds the sun shell to make second and sixth, so a slipping or broken shell can show up as missing second and sixth gears.
GM bulletin 23-NA-224 lists filter 24236517 and seal 24225347, ordered separately. Replace both whenever the pan is off for a rebuild.
Do not. The 6L90 uses a longer case and stronger gearsets, and many internal dimensions differ from the 6L80.
