In 4th Gear, signal A oil force must overpower the 1-2 shift valve spring and opposing signal B pressure in GM 4L80-E and 4L85-E transmissions. If the 1-2 shift valve does not remain fully stroked, drive oil to second and direct will be cut off or go to exhaust. The reaction area of A is greater than that of B, so the spring is the stroking factor. Complaints of 2nd Gear starts, Neutral after 2-3 shift or no 4th Gear are compounded by worn AFL limit bores, leaking O-rings and solenoids. When AFL oil drops, and signal A becomes less than 58 psi, the 1-2 valve will stall or float. This 3-1 or complaint of 3rd Neutral will occur in OD or D with scanner indication of 4th commanded. Sonnax 1-2 and 2-3 shift valve spring kit 34994-02K replaces the original 1-2 shift valve spring and 2-3 shift valve spring.

Set allows salvage of stripped cores
Restores signal pressure to shift solenoids
Improves shift

More From This Category

Sonnax Solenoid Relay Valve Kit, Aisin Aw, Aw55-50Sn/51Sn & Af23/33, Each

Sonnax Solenoid Relay Valve Kit, Aisin Aw, Aw55-50Sn/51Sn & Af23/33, Each

$75.52

MANLEY Valve Spring, NexTek, Drag Race, 1.340 in. OD, 394 lbs./in. Rate, 1.050 in. Coil Bind Height, Dual, Set of 16

MANLEY Valve Spring, NexTek, Drag Race, 1.340 in. OD, 394 lbs./in. Rate, 1.050 in. Coil Bind Height, Dual, Set of 16

$856.38

Crow Cams 10 Deg SQUARE GROOVE -.050"

Crow Cams 10 Deg SQUARE GROOVE -.050"

$107.57

MANLEY Valve Spring Retainer, Titanium, Super 7 Degree, 1.560 in. OD, Each

MANLEY Valve Spring Retainer, Titanium, Super 7 Degree, 1.560 in. OD, Each

$55.61

COMP Cams VALVE SPRING & STEEL RETAINER KIT, ZEX

COMP Cams VALVE SPRING & STEEL RETAINER KIT, ZEX

$670.55