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The straight-forward approach and overall simple design will allow a seamless integration of any 3rd or 4th Generation Chevrolet Small Block with the readily available and robust FS6R31A Nissan Transmission found in the Z33 350Z and Inifniti G35. This transmission, model number FS6R31A, is a smooth and tough six speed. The FS6R31A will have one of two numbers (CD #1, CD#2) indicating this update. Transmission Stamp.

Gearbox Swaps
Types: 56 60 63 71 90 R30
Transmission Swaps
5-Speeds F5C56A Stumpy
Toyota 5-speed
Manual/Auto conversion
more: Transmission Modifications

6-speed transmission gives you two (count 'em 2) overdrive gears. Or some have a close ratio direct-5th with overdrive, which is better for performance. 6-speeds can be modified to fit Datsun 1200. Just cut the bellhousing and weld on a fragment of A-series bell housing, then machine the input shaft smaller.

Ka24de 5 Speed Transmission

  • 3S15 6-speed

6-speed with A-series bell grafted on
Album click to view


The basic Aisin AZ6 gearbox was made in several versions, with front cases for these engines:

  • Nissan FS6R30A (source: Nissan pickup 2004-)
  • Nissan FS6R31A for SR20DET (source: S15)
  • Nissan FS6R31A for VQ35 (source: Z33)
  • Nissan FS6R92A for VQ35 (source: G35) 130 lbs weight
  • Nissan FS6R92A for SR20 (source: S15)
  • Mazda Renesys (RX8 rotary)
  • Mazda Y16M-D F & B (1999-2005 MX-5)
  • Toyota J160 for 1G & 3S (E10 Toyota Altezza/Lexus IS200)
  • Toyota 86/Scion FR-S
  • Subaru BRZ

A limited run was produced of custom front cases for Toyota T-50 bellhousing, so with this gearbox a Dellow kit might work to mate it to the A-series engine.

But other wise, use the Cut-n-Shut method.

Nissan RWD six-speed is plentiful in wrecking yards and inexpensive new ($1800) or used ($900). Use an adapter plate and bob's your uncle. Reportedly 3x stronger than an SR20DET 5-speed. It is a true direct-fifth gearbox + overdrive.

  • Z33 '350Z' 2003-
  • 2005- six-cylinder Frontier, Xterra, Pathfinder

Album click to view


The 1999-2002 Nissan Silvia S15 Strawberry with SR20DE/SR20DET had an optional close-ratio 5-speed + overdrive (6 forward speeds total). In AUS, the six-speed was in the Nissan 200SX Spec-R model.

S15 modified; A-series bell grafted on
Album click to view

  • FS6R92A
  • only 16kg heavier than a standard 1200 4spd
  • Close ratio 1-5, with overdrive 6th. It is perhaps the best ratios for an A-series engine

Gear Ratio

Comparison with A-series 5-speeds

Comparison with S14 5-speed

Comparision of various Aisin AZ6 models:


Pilot Bushing

S15 5-speed FS6R92A

  • used on L, Z, VG, VQ, SR, KA, and CD engines (same as 71C bushing)
  • Pilot Bushing Inside Diameter: 0.626 to .6300' (Length: .689')
  • Pilot Bushing Outside Diameter: .814 to .815'

Since this is much larger in diamter than the A-series, machining is needed.

A-series crankshaft bore is for a bushing with 0.671' O.D., length .723'

  • The FS6R92A input shaft end can be turned down to ~.671 O.D.
  • Could the A-series crank pilot hole be bored out to .814' so the 71-Series bush can be fitted?

Input shaft end turned down to smaller diameter

Clutch Disc

Fs6r31a transmission

FS6R92A clutch disc [all 240mm]

  • 30100-85F00 9901-0011
  • 30100-85F14 0011-
  • Spline O.D.: 1'
  • Spline: 24 teeth

There is an A-series clutch disc that is 1' x 24T: 30100-K0500.


Input Shaft Length

How far does the FS6R92A input shaft extend past the transmission face?

  • 5-speed: about 17mm past the flange
  • 6-speed: about 10mm inside the flange


S15 6-speed does not have a speedometer gear.


Clutch Release

How to connect up the clutch?

Gearshift Location

Comparision of Nissan 6-speed with long-5-speed and short 4-speed. The location of the shifter is close to the location of stumpy gearbox shifter.


Rear Crossmember

Use a generic crossmember to fit a 6-speed.

Fs6r31a Cd009

Propeller Shaft

The 6-speed overall length is greater than a stumpy gearbox, but not as long as a a longtail Nissan transmission.

6-speed vs 71C long vs 71B long vs F4W63 stumpy


A limited run was produced of custom front cases for Toyota T-50 bellhousing, so with this gearbox a Dellow kit might work to mate it to the A-series engine.

Aisin AZ6 with custom front case for T-50 removable bell housing. A custom input shaft is used.

Toyota J160 dimensions

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Optimal Manual Transmission Maintenance Tips

For Maintaining Transmission Performance

Both the CD009 6-speed and RS5R30A 5-speed manual transmissions are great options to consider for a transmission swap. Despite being solid choices, age can sometimes deteriorate their performance. That’s why proper manual transmission maintenance is so important.

Maintenance goes a long way toward keeping your transmission in optimal condition. However, even when done properly, at some point replacing worn parts is the only way to restore transmission performance.

Here are three important elements for preventive maintenance and eventually restoring your transmission.

Checking the Transmission Fluid

Fluid in a manual transmission should be changed at regular intervals as specified in your owner’s manual. Although seemingly minor, transmission fluid plays a huge role in how your shifter feels and engages. Unfortunately, many owners neglect this simple job which leads to notchy shifting, trouble engaging new gears, and unnecessary wear and tear on transmission components.

Transmission Fluid Change vs Flush

Anyone who experiences grinding between gears or tough gear changes and who is looking to restore factory performance should perform a transmission flush.

If you want to go a step further and improve shifter feel, consider replacing the transmission fluid with a performance product. Pennzoil, Redline, Royal Purple, and Amsoil all offer excellent options.

Clutch Components

Although your clutch is not a direct component of your transmission, its role in shifting is paramount. Performance clutches can improve shifting feel, and response. When combining a performance clutch with a lightweight flywheel that allows you to shift faster, driving experience is greatly improved.

Shifter Bushings

After years of use and the associated corrosion, the plastic shifter bushings located through your shifter linkages begin to wear. The result is a shifter with a sloppy and loose feel. To restore your shifter tightness, replace your shifter bushings and your shifter spring. Afterward, the tightness and precise feel during shifting will surprise you.

6 Speed Fs6r31a Manual

Transmission Restore or Manual Transmission Swap

However, sometimes even with proper maintenance and the strategic replacement of worn parts, at some point a manual transmission swap becomes the better alternative than restoring your transmission.

Manual Transmission Swap Kits

The Z32 5-speed and Z33 6-speed manual transmissions are popular choices among car enthusiasts. General information about each of these transmissions is provided in the charts below. If you’re considering a manual transmission swap, these details will come in handy. G Force offers adapter kits for both a Z32 ls swap and a Z33 ls swap.

Nissan 300zx Manual Transmission Swap

For a Nissan 300zx manual transmission swap, an affordable alternative to the pricey t56 or weak gm 5 speeds is an ls transmission adapter kit. An ls transmission adapter kit will allow you to mate a Nissan 300zx (Z32) 5 speed transmission to an ls series engine.

300zx ls transmission adapter for a Nissan 300ZX 5-speed Manual Transmission

Z32, 1990 – 1996

Cd001 Vs Cd009

This fourth (4) generation Nissan 300ZX used a Z32 chassis and offered a 5-speed manual shifted transmission. This transmission was known as a # RS5R30A, 5-speed, manual unit, featuring the new double-cone synchronizers. The 5-speed stick-shift is very strong and a rock-solid unit.

1st Gear3.21
2nd Gear1.92
3rd Gear1.30
4th Gear1.00
5th Gear.75

Final Consideration – Gearing

The last thing to consider about this transmission is the gearing. Gearing plays a huge role in how your vehicle performs. Long gear ratios accelerate slow, but offer higher top speeds and less shifting time, while shorter gear ratios will help accelerate your car faster but force you to shift more often. When considering gear ratios, the lower the number, the higher the gear ratio.

When comparing the ratios between the CD009 and T-56, it becomes apparent that the T-56 offers much longer gears. For those looking to remain in the powerband of their motor on the track or with spirited driving, a CD009 is a great option. However, a T-56 performs better in drag racing applications where the longer gears reduce shifting time.


YearUS Sales

G Force Performance Products is your go-to manufacturer for bellhousing adapters and flywheels for your GM LS engine or Vortech engine into 300ZX cars, while using its own Nissan OEM Z32 5-speed manual transmission.

Nissan 350z Manual Transmission Swap

For a Nissan 350z manual transmission swap, an affordable option is an ls transmission adapter kit. An ls transmission adapter kit will allow you to mate a Nissan 350Z (Z33) 6 speed transmission to a LS Series, Gen III or IV, Chevrolet Small Block Engine.


Fs6r31a Transmission Rebuild Kit

LSX 350z Transmission Adapter for a Nissan 350z 6 Speed Manual Transmission or an Infinity G35 6 Speed Manual Transmission

Z33, 2005 – 2006

The fifth (5) generation Nissan 350z used a Z33 chassis and offered several models of 6-speed manual transmission. Although other 6-speed transmission were offered from 2003-2004 designate, updates in mid-2004 lead to a much stronger transmission offered from 2005-2006 offering triple cone synchronizers in 1st, 2nd, and 3rd gear. This transmission, model number FS6R31A, is a smooth and tough six speed.

The FS6R31A will have one of two numbers (CD #1, CD#2) indicating this update.

Transmission StampTransmission Code NumberYears
CD #1CD00803-05 6MT
CD #2CD00906-07 6MT
YearUS Sales
2008 10,337
2009 3,819