Signal accumulators are used in Gen. 2 and 3 GM 6T40 transmissions to dampen or smooth out the signal fluid pressured applied from each control solenoid before the fluid flows to the control valve. These components help provide a smooth operation of the transmission.

When the bore and/or pistons wear out, they cannot effectively dampen the variation in pressure. This can result in poor shifting control (soft shifts), no converter apply, hydraulic-related converter warning codes and ultimately a burnt clutch.

Replacing these worn out accumulators can require replacing the valve channel casting or entire control valve body or reaming out the bore and installing an oversized piston.

Sonnax drop-in signal accumulator piston kit 144740-40K allows long-lasting and quick repair of the valve channel casting without reaming. The O-ring provides a positive seal against critical pressure loss even in worn bores.

• Hardcoat anodized aluminum piston combats premature wear
• Annular groove added to reduce wear rate
• Highly wear-resistant sleeve to prevent future wear
• O-Ring provides positive seal to prevent critical pressure leakage in already worn bores
• Mating spring to re-establish OE dampening action
• Drop-in Zip Valve™ parts install quickly and easily