Every gasket, seal, O-ring, and clutch piston lip seal the 4L60E needs to go back together sealed tight, in one kit.
A 4L60E or 4L65E that leaks from three places, slips once it is warm, or takes a second to grab Drive after sitting overnight is usually telling you the same thing: the rubber inside it is done. This KP33900EF overhaul kit covers the 1993 through 2003 GM rear-drive four-speeds found behind the small block in Silverado and Sierra 1500s, Tahoes, Yukons, Suburbans, S10 and Sonoma pickups, Blazers and Camaros, plus the heavier-duty 4L65E GM paired with its 6.0-liter V8 in the early 2000s. It is the reseal half of a rebuild: gaskets, metal-clad lip seals, sealing rings, O-rings and square-cut seals, along with the clutch piston lip seals that decide whether each clutch pack actually clamps.
The 4L60E and 4L65E share the same basic layout: four clutch packs in the rotating input section, a low/reverse clutch at the rear, and a 2-4 band applied by a servo. None of those devices are mechanical. Each one is a piston pushed by line pressure, and the clutch piston lip seals, the inner and outer servo seals, and the Teflon sealing rings on the input shaft and stator shaft are what route that pressure to the right drum. When those seals harden, pressure leaks to the sump before it ever reaches the clutch, so the pack applies soft and slips, and the slipping cooks the friction material. Replacing every seal in one pass restores full apply pressure to clutches and steels that are still in good shape. The 4L65E differs inside mainly in its gear train and clutch capacity, which is why one seal kit can cover both units.
Pull the pan. A clean pan and pink fluid means the frictions are healthy and a reseal is the right job. A pan full of black paste and steel flakes means the unit needs hard parts and a full friction kit too. Our 4L60E 2-4 band and servo guide explains how servo seal leakage shows up as band slip, and the 4L60E common problems guide separates seal-related failures from the sun shell and valve body problems this kit will not touch.
The listing covers 1993-2003 GM 4L60E and 4L65E units, and some Isuzu applications that used the same transmission. Inside that range GM changed the valve body spacer plate, the converter clutch control and the internal harness more than once, so lay each gasket over the original before installing and use the one that matches your parts. Check the transmission ID tag to confirm 4L60E versus 4L65E, and if you are unsure, send us your year, model, engine and VIN. For 2004 and later units, see the matching kits on the 4L60E parts collection.
Refill with Dexron VI, check the level hot with the engine running, and drive easy for the first few hundred miles.
| Fits | GM 4L60E / 4L65E, 1993-2003 (some Isuzu) |
| Type | Overhaul / reseal kit (gaskets and seals) |
| Includes | Gaskets, metal-clad seals, sealing rings, O-rings, clutch piston lip seals |
| Part number | KP33900EF |
| Note | Verify year, make, model, and engine for fitment |
Doing this repair right usually means replacing these at the same time. Same transmission, ships together.
Yes, the KP33900EF kit is listed for both the 4L60E and 4L65E from 1993 to 2003. Match each gasket to your original parts, since GM revised the valve body plate during that run.
Only if the old ones are burnt. This kit is seals and gaskets only. If the frictions are glazed or the fluid is black, add a friction pack or use a master rebuild kit.
New 3-4 piston seals help, but repeat 3-4 failures usually also involve low line rise, valve body wear or a weak 3-4 apply. Check those before closing the case.
Dexron VI ATF. Fill to the mark with the engine running and the fluid at operating temperature.
No. This kit is listed through 2003. Look for a 2004-and-later 4L60E overhaul kit on our 4L60E collection page.
