|Frequently Asked Questions|
Accumulator Valve Train Assembly, Heavy Vehicles - GM 2004R, 4L60, 4L60E, 700R4
Part Number: SX-77777M-K
Do You Need Trans-Prep Assembly Lube?
Do You Need Trans-Flush Transmission Flush?
Vehicles with a 200-4R, 700-R4, or 4L60-E transmission can experience 1-2 light throttle abrupt
or "bang" shifts, especially when using the "093" Corvette or "553" 2nd apply servo pistons. The
current industry solution is to make the servo piston apply diameter smaller. However, this limits
the 2-4 band life. This shift problem can occur due to sleeve wear allowing torque signal and/or
accumulator pressure leakage, or when the accumulator valve is too large for the application,
resulting in too much pressure on the 2-4 band. This valve train has multiple OEM size variations,
including B, A, N, M, L, K, and F. The size variations are clearly stamped with the letter on the
aluminum sleeve. Most vehicles, depending upon the transmission/engine combination, can use
either the M, L, or K version. However, these are not available unless scavenged from other valve
bodies. Sonnax has designed three replacement accumulator valve train assemblies: 77777M-K
for the M (.341" valve diameter); 77777L-K for the L (.330" valve diameter); and 77777K-K for
the K (.315" valve diameter).
Features & Benefits
Sleeve is manufactured from high-quality aluminum designed to prevent excessive wear due to
the reciprocating motion of the steel valve.
Each kit contains three springs of varying spring rates to select from to obtain proper shift feel.