Transmission Parts

Browse all Sonnax transmission parts here, or use the filters below to find just what you are looking for.

Find a Distributor

Looking for Part Instructions?

View Sonnax Part Instructions

Enter a Sonnax part number below to view its instructions. For general reaming instructions, click here.

U140E • U140F • U240E • U241E

Oversized Pressure Regulator & Boost Valve Kit 57917E-08K

Helps cure:

Soft shifts
Low line pressure
Harsh shifts
High line pressure
Clutch & band failures
High line pressure in Reverse
Low converter pressure

1000/2000/2400

Trim Valve & Spring Kit 37000-12K

Fits ’00–’09 units only. The F-trim spring is applicable to ’00–’05 valve body casting only.

Helps cure:

Premature clutch wear
Inability to alter clutch apply pressure curve

5R110W

Oversized Manual Valve 36940-11

Replaces OE valves with or without holes in long spool.

Helps cure:

Damaged valve body casting
Low line pressure
Delayed Drive
Delayed Reverse

55-50SN • 55-51SN

Oversized Pressure Regulator & Boost Valve Kit 59947-12K

Also fits AF23/33 and RE5F22A.

Helps cure:

Soft shifts
Delayed shifts
Delayed engagement
TCC apply & release concerns
Harsh shifts

1000/2000/2400

E-Shift Valve Spring 37000-02

Fits '00-'09 units only.

Helps cure:

Code P0872
Code P1711
Pressure switch stuck on
Failsafe mode
3rd Gear starts

4R44E • 4R55E • 5R44E • 5R55E

Pressure Regulator Sleeve Kit 37947-05K

Helps cure:

Delayed engagement
Poor shift quality
Low line pressure
High line pressure
Overheating
Low cooler flow at idle

4R44E • 4R55E • 5R44E • 5R55E

TCC Regulator Sleeve Kit 37947-09K

Helps cure:

Code 628, 1741
TCC apply concerns
TCC cycling
TCC surge
High TCC slip RPM
Overheated fluid
Overheated converter

5R55S • 5R55W

Reverse Engagement Valve Kit 56947J-29K

Helps cure:

Delayed Reverse
No Reverse
Slipping gears
Direct clutch burned

4R100 • E4OD

Oversized Solenoid Regulator Valve 36947-14

Fits '96-later, 2-spool valve

Helps cure:

2nd Gear starts
3rd Gear starts
TCC cycling
TCC slip
Reduced lube oil from the center support

4R100 • E4OD

Line Pressure Modulator Plunger Valve Kit 36948-05K

Dia.: 0.372"

Helps cure:

Intermittent harsh shifts
1-2 Soft
2-3 Soft
Low line rise
Low EPC pressure

TF-81SC

Solenoid Modulator Accumulator Piston Kit 39741-14K

Fits Ford (AF21) and Mazda (AW6A-EL) units. Fits either of two locations.

Helps cure:

Shift concerns
Shift codes
Low solenoid feed pressure

5R55N

TCC Back Pressure Spring 56947J-S5

Helps cure:

Harsh TCC apply
Excess TCC slip
Low line pressure
TCC lining overheat

U140E • U140F • U240E • U241E

Clutch Apply Control Plunger Valve Kit 57917E-05K

Helps cure:

Shift concerns
Erratic shifts
Clutch failure

5R55N • 5R55S • 5R55W

TCC Modulator Valve Kit 56947J-15K

Helps cure:

Code P0741
Excess TCC slip
Code 1783
High line pressure
Overheated transmission

JR710E • JR711E • JR712E • RE5R05A • RE7R01A

Oversized Pressure Regulator & Boost Valve Kit 63741-01K

Also fits Hyundai/Kia A5SR1/2 and Subaru 5EAT.

Helps cure:

Delayed Forward
Harsh Reverse
Erratic line pressure
2-3 Harsh
Low converter & lube flow
Burnt clutches
Excess clutch apply pressure
Delayed Reverse
Reverse slip

↑