Complete Corvette-style 2-4 servo assembly for the GM 4L60E (and 700R4), ready to install. Larger apply area for firmer 1-2 and 3-4 shifts and a stronger 2-4 band hold.
If your Silverado, Tahoe, S10, Camaro or Corvette with a 4L60E (or the 700R4 before it) feels like it slides into second, flares on the 3-4 shift, or drops out of fourth on a hill, the 2-4 band is not getting squeezed hard enough. This is a complete, ready-to-install Corvette 2-4 servo assembly: the larger-area servo GM used in the Corvette, built up with its cover, apply pin, return spring, seals and snap ring so it drops into the case bore as one piece.
The 2-4 band wraps the reaction sun shell. In second and again in fourth gear, the band has to clamp that shell solid, and the servo is the hydraulic piston that does the clamping. Line pressure acts on the servo piston, the piston pushes the apply pin, and the pin tightens the band. More piston area at the same pressure means more clamping force, which is the whole idea behind the Corvette servo. Sonnax describes the stock 4L60 second gear servo as coming in several OE sizes, with the Corvette size the common upgrade over the smaller truck and car servos.
Release matters as much as apply. On the 2-3 shift the band lets go while the 3-4 clutch comes on, and the 4L60/E servo is built with a release area larger than its apply area so the band is pushed off hydraulically rather than relying on the spring alone. That balance is why a correctly assembled servo with good seals gives a clean 2-3 without a bind-up.
Missing second and fourth together is the classic sign. Transmission Digest points out that the 2-4 band is the only element applied in both of those gears, so losing both sends you to the band, the servo, or the sun shell it holds. A sun gear that has broken loose from the shell gives a similar complaint, so inspect the shell if the transmission is coming apart anyway. Work through our 4L60E common problems guide and the S10 shift problems diagnosis before you order, and check fluid level and condition first.
The assembly is listed for the GM 4L60E (1993-2013) and the 700R4 it grew from (1982-1993); the 1982-2014 in the title is that combined family range. That covers the full-size Chevrolet and GMC trucks and SUVs, S10 and Sonoma, Blazer, Camaro, Firebird and Corvette applications that used these units. If you have a 4L65E or 4L70E, or a case that has been machined for an aftermarket servo, send us your year and VIN before ordering so we can confirm the bore. Browse the rest of our 4L60E parts for the matching hard parts.
Expect firmer, shorter 1-2 and 3-4 shifts afterward. That is the point of the part, and on a tow rig it means less heat in the band.
| Fits | GM 4L60E (1993-2013) and 700R4 (1982-1993) |
| Type | Corvette-style 2-4 servo assembly, ready to install |
| Includes | Servo piston assembly with cover, apply pin, return spring, seals and snap ring |
| Function | Larger 2-4 band apply area for firmer 1-2 and 3-4 shifts |
| Installation | Through the case servo bore, transmission in the vehicle |
Doing this repair right usually means replacing these at the same time. Same transmission, ships together.
It is listed for the GM 4L60E from 1993-2013 and the 700R4 from 1982-1993, which includes full-size Silverado, Sierra, Tahoe, Yukon and Suburban, plus S10, Blazer, Camaro and Corvette. For a 4L65E, 4L70E or a modified case, send your year and VIN and we will confirm before it ships.
Yes. The 2-4 servo sits in a bore on the passenger side of the case behind a cover and snap ring. With the vehicle safely raised you can remove the old servo and install this one in place, then top off the fluid.
Measure apply pin travel with a servo pin gauge when you install it. The pin included suits stock band clearance, but a worn band or drum can change what length is needed, and the wrong pin can cause slipping or a bind on the 2-3 shift.
Only if the servo or its seals are the cause. No 2nd and no 4th can also come from a burnt 2-4 band or a sun gear broken away from the reaction shell. Check those before assuming the servo alone will fix it.
Use Dexron VI ATF, which is the current GM fluid for the 4L60E. Lubricate the new seals with it before installation and check the level at operating temperature when you are done.
