Line Press. Booster TH400

Sonnax hydraulic line pressure booster kits contain stronger pressure regulator springs and large ratio boost valves designed to work together to provide progressive pressure increases as driving conditions become more demanding. Our pressure regulator springs are approximately 10% stronger than OE and more conservative in impact than other aftermarket kit springs. Large ratio boost valves provide higher pressure incrementally and when it is needed the most. The combination of these springs and valves in a Sonnax kit gives you the best of both worlds: a modest pressure increase at the low end, with a high-end pressure that is equal to or greater than that of other aftermarket kit springs. Achieve shorter shifts and increased torque capacity without creating low-speed harshness Improved band and clutch holding capacity for increased durability Progressive pressure increase as driving conditions become more demanding All the benefits of increased line pressure without overloading the pump at idle Simple and affordable drop-in solution with no special tools or reaming required

1965-ON

TH400 Steel Module. 000357 features 2 Intermediate, 1 Intermediate (Waved), 4 Forward (Except Cad & Olds), 5 Forward, Direct, 1 Forward, Direct (Waved) Steel Clutch Plates.

Washer Pump TH400 oversize [5]

Package Quantity: 5

• Outer Dia.: 1.780"
• Inner Dia.: 1.405"
• Thickness: 0.094"

• Material: Steel

Washerset TH400, 4L80E Fwd Hub

Package Quantity: 5

• Outer Dia.: 1.781"
• Inner Dia.: 1.289"
• Thickness: 0.078"

• Material: Steel

Press.reg valve OS 4F27E,FN5

• Valve 
• End Plug (Ford only)

 Ford/Mazda 4F27E, FN4A-EL, FNR5 and FS5A-EL units may exhibit multiple line pressure and converter-related problems due to excess wear in the pressure regulator bore. Wear at the balance spool end allows critical fluid loss, resulting in high line pressure, harsh shifts, and overheating due to reduced cooler/converter/lube flow. Wear at the outboard spool area robs converter feed pressure and lowers line pressure, causing soft shifts and burnt clutches and bands. Reconditioning the bore and installing Sonnax oversized pressure regulator valve kit 46892-01K restores hydraulic integrity for proper line pressure control in all ranges.