Cause:
Lack of sufficient holding power in the overdrive roller clutch.
Correction:
Apply the overrun clutch in all gears except OD 4th, reinforcing the roller clutch to adequately support heavy loads.
Insufficient holding power in the overdrive roller clutch is the underlying cause of chronic overdrive roller clutch failure in hardworking 4L80-E and 4L85-E transmissions. When the roller clutch fails, the damage can be catastrophic and the only fix is replacing the drum, planetary assembly and mating components.
This Sonnax Smart-Tech overrun clutch valve kit offers a hydraulic solution to this known mechanical problem. With unique rerouting of hydraulic fluid pressure, this patented kit keeps the overrun clutch applied at all times (except OD 4th), reinforcing the roller clutch to adequately support heavy loads.
Improves OD roller clutch holding power in D4 and Reverse ranges
Extends the life of workhorse transmissions while preventing warranty claims and comebacks
Installs quickly onto the valve body — no transmission removal needed
Range
Gear
Overrun Clutch with Sonnax Clutch Valve Kit
Overrun Clutch with OE Clutch Valve
Park
Applied
Reverse
Applied
Neutral
Applied
Overdrive
1st
Applied
2nd
Applied
3rd
Applied
4th
Drive
1st
Applied
Applied
2nd
Applied
Applied
3rd
Applied
Applied
D2
1st
Applied
Applied
2nd
Applied
Applied
D1
1st
Applied
Applied
Note:
Any other modifications to the valve body should be completed prior to installing Sonnax Smart-Tech® overrun clutch valve kit. With minor lube tube modification, the Sonnax kit can be installed in ’92-’96 units.
Symptoms:
Cause:
Lack of sufficient holding power in the overdrive roller clutch.
Correction:
Apply the overrun clutch in all gears except OD 4th, reinforcing the roller clutch to adequately support heavy loads.
Insufficient holding power in the overdrive roller clutch is the underlying cause of chronic overdrive roller clutch failure in hardworking 4L80-E and 4L85-E transmissions. When the roller clutch fails, the damage can be catastrophic and the only fix is replacing the drum, planetary assembly and mating components.
This Sonnax Smart-Tech overrun clutch valve kit offers a hydraulic solution to this known mechanical problem. With unique rerouting of hydraulic fluid pressure, this patented kit keeps the overrun clutch applied at all times (except OD 4th), reinforcing the roller clutch to adequately support heavy loads.
Note:
Any other modifications to the valve body should be completed prior to installing Sonnax Smart-Tech® overrun clutch valve kit. With minor lube tube modification, the Sonnax kit can be installed in ’92-’96 units.
Contents:
SONNAX Installation Instructions