Nissan SR20/CA18/KA24 gearbox info – FS5W71C

Nissan FS5W71C gearbox 3-4th gear selector fork problem

There are two types of 3-4th gear selector forks and synchros. Early models used small aluminum fork, small synchros, while later more powerful models used uprated synchros and forks. Old/small design forks brake due to weak part material, design and hard gear changes.

S13 CA18DET prefacelift (1988-89), small aluminum 3-4th fork (not supported on other forks), small 3-4th synchros
32811-58S00, 32811-58S10

S13 CA18DET facelift (1990-93), big steel 3-4th fork, big synchros
32811-80S10, 32811-15U00

S14/S14A SR20DET (1994-99) – big 3-4 gear selector fork, big synchros

S13 KA24E/DE (1988-1993), S14 KA24DE (94-98) – small 3-4th fork/synchros (same as prefacelift CA18)
32811-58S00, 32811-58S10

JDM S13 SR20DET uses uprated 3-4th fork/synchros

S13 SR20DET blacktop on top, S13 KA24DE on bottom
pic from

Center bearing/gear mounting plate

Center bearing/gear mounting plate seems to be the same part number on all EU/US S13/S14 CA18/SR20/KA24 gearboxes. There were rumors that late S14 models used uprated center plate with better oil passages to prevent oil accumulation in the rear housing on acceleration but I haven’t found anything different YET.

Gaskets and seals

Front cover seal – 32112-08U01

Shifter cover gasket – 32516-03U11

Shifter rubber boot – 32862-V5002

Front (input shaft) oil seal – 32114-Y4000, Musashi N2038, Corteco 12018345B, NOK AH1679G – 30x45x7
Rear (output shaft) oil seal – 32136-U0100, Musashi N2045, Corteco 19016609B, NOK AH2080E – 35x50x11
Oil seals are the same in all Nissan/Datsun small case 4/5 speed gearboxes – F4W71B, FS5W71B, FS5W71C

Throw out bearings

S13/S14 oem uses 30502-21000 with 40mm id, 62mm contact diameter, 18mm height.
Aftermarket twin disc usually uses 40mm id, 44mm contact diameter bearings.

ID 40mm, OD 67mm, Height 19mm, Contact diameter 44mm – Koyo RCT4067L1, NSK TK40-1B2, Nachi 40TSK-2, Nissan 30502-14601
ID 40mm, OD 64mm, Height 16mm, Contact diameter 50mm – Koyo RCT4064S
ID 40mm, OD 70mm, Height 20mm, Contact diameter 50mm – Koyo RCT40
ID 40mm, OD 75mm, Height 19mm, contact diameter 62mm – Koyo RCT4075-1S, NSK TK404A, Nachi 40TRK1, NTN SF08202E, 30502-21000 S13/S14