When a 2004-or-newer Silverado, Sierra, Tahoe, Suburban or Yukon starts flaring on the 2-3 or 3-4 shift, slips when the truck is loaded, or leaves black, gritty fluid on the dipstick, the 4L60E or 4L65E behind it is usually coming out for a full teardown. This super master kit is the box to have on the bench when that happens. It goes past a normal overhaul kit by adding the Raybestos friction module with high-energy 3-4 plates, a matched 22-piece steel set, a 3-piece molded piston set, a Borg Warner 2-1/4 inch band, a thrust washer kit and a deep pan filter, so every wear item in the unit is new at the same time.
What a super master kit does in a 4L60E
The 4L60E builds its four forward gears and reverse by applying five clutch packs and one band in different combinations. The 3-4 clutch inside the input housing carries the engine's full torque in 3rd and 4th, and it is the pack that burns first in most failed units. The 2-4 band wraps the reverse input drum and holds it for 2nd and 4th. Every pack also needs a piston to squeeze it and seals to hold apply pressure, and the gear train rides on thrust washers that control end play. A standard overhaul kit renews the seals and gaskets only. This kit renews the frictions, the steels that absorb clutch heat, the pistons themselves and the band, which is why it is the right choice for a unit that has already burned material rather than one that simply leaks.
Symptoms that call for this kit
- No 3rd or 4th gear, or a 3-4 shift that slips and then grabs, from a burned 3-4 clutch pack.
- Slipping or a soft, long 1-2 shift and slip in 4th, which points at a glazed 2-4 band or a leaking servo circuit.
- Burnt-smelling fluid with clutch material and metal in the pan.
- Delayed engagement into drive or reverse once the fluid is hot.
- No 3rd or 4th with the 3-4 pack still looking good at teardown. That is often a stripped sun shell, which is a hard part this kit does not include.
How to confirm the failure before you order
Pull the pan first. A dark film is normal wear; flakes of friction material, a layer of brass or steel debris, or fluid that smells scorched means the packs are done and a reseal will not hold. Scan for codes, because a P0741 converter clutch slip or a P0748 pressure control solenoid fault can mimic a mechanical failure and may be a valve body or solenoid problem instead. Our 4L60E common problems guide walks through separating the clutch failures from the hydraulic ones, and the 2-4 band and servo guide covers band wear and servo pin selection.
Fitment
This kit is built for the 2004-and-later 4L60E and 4L65E used in the GM rear-drive trucks and SUVs of that era. GM revised hard parts more than once during production, so confirm your year, make, model and engine before you order. If you are not sure which generation you have, send us the year and VIN and we will check it. You can browse every part we carry for this unit on the 4L60E parts page.
Install notes
- The band in this kit is the wide 2-1/4 inch style. Sonnax warns never to fit a wider band to a used drum, because the old band dishes the drum surface and the new band will slip and glaze on it. Plan on a new or properly resurfaced reverse input drum.
- Set servo travel with a dial indicator, roughly 0.075 to 0.125 in per Sonnax, and do not shim the servo to change it.
- Check gear train end play on assembly. Transmission Digest gives 0.005 to 0.036 in as the range with 0.020 to 0.025 in preferred; the thrust washer kit gives you the fresh surfaces to hit it.
- Soak all new frictions in Dexron VI ATF before stacking and fill with Dexron VI.
- The deep pan filter belongs in a deep pan. If you are adding one, the aluminum deep pan pairs with it; on a stock-depth pan, use a matching shallow filter.
- Inspect the pump for scoring before reuse; a worn one starves the new clutches. A replacement 2004-up 4L60E pump is the safer call on a high-mileage unit.
- Flush or replace the cooler and lines so old debris does not wash back into the new frictions.
