The Transmission / Differential FAQ

[Whizbang]

Updated: 7 Jan 2014

The following is a coming together of information for quick reference when looking for a gear ratio, transmission choice or any other information that may assist those looking to modify or repair there drive line. This thread will be updated periodically and reference to that will be via that date at the very top of this thread


Transmission Gear Ratios

Q. Can i use a Ford or Chevy transmission?
A. Yes, a couple of companies make adapters and bell housings to allow for a spread of transmissions including the Ford T5, various Chevy transmissions and Jericos.

See this thread here regarding swapping a T-5: T-5 Swap

For the Ford T5 see Rotaryshack or Kennedy Engineering.

For Chevy transmissions see J.W. Performance Transmissions Page 17

For Jerico transmissions see J.W. Performance Transmissions Page 17

For VW transmissions see Kennedy Engineering

Q. Are there aftermarket gear sets for my stock transmission case?
A. Yes,Pfitzner Performance Gearboxs (PPG) makes several options. OSGiken also makes sets for the FD3S and FC3S Turbo II.

Pfitzner Performance Gearbox

• 5 speed dog engagement gearset
• Series 1-5 billet shifter platform
• Short shifter assembly
• Hardened billet selector fingers

OSgiken

3 Speed Kit for the FC/FD:
1st: 2.714
2nd: 1.742
3rd: 1.267

5 speed kit for the FC/FD:
1st: 2.578
2nd: 1.772
3rd: 1.289
4th: 1.000
5th: 0.821

Q. What about the Miata gearset swap?
A. See this thread here for some good information: Miata Gears

Q. Can i swap an Rx8 Transmission?
A. Yes, but read this thread throughly first: Rx8 Transmission

Factory Transmission Ratios

Please note that the there can be variances in the fifth gear of the transmission depending on the sales market (Japan, USA and UK)

Mazda Rx2, Rx3, Rx4, Rx5 (Cosmo) 12A/13B Gearbox
1st: 3.380
2nd: 2.002
3rd: 1.390
4th: 1.00
5th: 0.791

Mazda Rx3SP 77-78 Gearbox
1st: 3.380
2nd: 2.002
3rd: 1.390
4th: 1.00
5th: 0.791

Mazda Rx-4 77-78 13B Gearbox
1st: 3.380
2nd: 2.002
3rd: 1.390
4th: 1.00
5th: 0.791

Mazda Rx-5 (Cosmo) 77-78 13B Gearbox
1st: 3.380
2nd: 2.002
3rd: 1.390
4th: 1.00
5th: 0.791

Mazda Rotary Engined Pickup 74-75
1st: 3.683
2nd: 2.263
3rd: 1.397
4th: 1.000

Mazda Rotary Engined Pickup 76-77
1st: 3.683
2nd: 2.263
3rd: 1.397
4th: 1.000
5th: 0.862

Mazda Miata Gearbox
1st: 3.136
2nd: 1.888
3rd: 1.330
4th: 1.00
5th: 0.814

89-93 B2600 "R" Transmission
1st: 3.730
2nd: 2.158
3rd: 1.396
4th: 1.000
5th: 0.816

Mazda Rx-7 early 12A Gearbox (4spd)
1st:
2nd:
3rd:
4th:

Mazda Competition Rx-7 Gearbox
1st: 2.350
2nd: 1.608
3rd: 1.240
4th: 1.00
5th: 0.881 or 0.839

Mazda Rx-7 79-83 12A Gearbox
1st: 3.674
2nd: 2.217
3rd: 1.432
4th: 1.00
5th: 0.825

Mazda Rx-7 79-85 Automatic Transmission (L4N71B)
1st: 2.458
2nd: 1.458
3rd: 1.00
4th: 0.720

Mazda Rx-7 84-85 12A Gearbox
1st: 3.622
2nd: 2.186
3rd: 1.419
4th: 1.00
5th: 0.758

Mazda Rx-7 84-85 13B (Type M) Gearbox
1st: 3.622
2nd: 2.186
3rd: 1.419
4th: 1.00
5th: 0.807

Mazda Rx-7 86 13B 6PI (Type M) Gearbox
1st: 3.475
2nd: 2.002
3rd: 1.366
4th: 1.00
5th: 0.711 (0.758 UK)

Mazda Rx-7 87-88 13B 6PI (Type M) Gearbox
1st: 3.475
2nd: 2.002
3rd: 1.366
4th: 1.00
5th: 0.697 (0.758 UK)

Mazda Rx-7 87-88 13B Turbo (Type R) Gearbox (also the 929)
1st: 3.458
2nd: 2.015
3rd: 1.391
4th: 1.00
5th: 0.762 (0.806 Japan)

Mazda Rx-7 89-92 13B 6PI w/o LSD Gearbox
1st: 3.475
2nd: 2.002
3rd: 1.366
4th: 1.00
5th: 0.697

Mazda Rx-7 89-92 13B 6PI with LSD Gearbox
1st: 3.475
2nd: 2.002
3rd: 1.366
4th: 1.00
5th: 0.756

Mazda Rx-7 89-92 13B Turbo Gearbox
1st: 3.483
2nd: 2.015
3rd: 1.391
4th: 1.00
5th: 0.719

Eunos Cosmo 90-95 20B-REW JATCO Automatic
1st: 2.78
2nd: 1.54
3rd: 1.00
4th: 0.69

Eunos Cosmo 90-95 13B-REW JATCO Automatic
1st: 3.03
2nd: 1.62
3rd: 1.00
4th: 0.69

Mazda Rx-7 93-95 13B-REW Gearbox
1st: 3.483
2nd: 2.015
3rd: 1.391
4th: 1.00
5th: 0.719 (0.806 Japan)

Mazda Rx-8 04-current 13B Renesis Gearbox (manual)
1st: 3.815
2nd: 2.260
3rd: 1.536
4th: 1.177
5th: 1.00
6th: 0.787

Mazda Rx-8 04-current 13B Renesis Gearbox (automatic)
1st: 3.538
2nd: 2.060
3rd: 1.404
4th: 1.000
5th: 0.713
6th: 0.582



Differential Gear Ratios

Q. Are the turbo stub shafts interchangeable?
A. Somewhat.

• 89-92 have a longer right side and a short left side.
• There is a vin split for the 86-88 shafts.. 608385+ are different the ones below that vin.

Q. I heard about the Kia Sportage and Mazda truck differentials, what are the facts about this?
A. I am going to break this up into two parts.

1. The Kia Sportage

• Available in the pre-2002 Kia Sportage. 1997 may not have the 4.78, but i have not been able to confirm this. Also, there may be another ratio other than the 4.78, but again, i have not come across them.
• The 3rd member is a direct bolt in to the 84-85 Rx7 axle housing.
• It is an open differential. But a LSD unit meant for an 84-85 rx7 will work fine in it.
• The holes on the kia member are larger than the Rx7 member, but it is not an issue.

2. The B2600

• Come from the 1987-1988 4x4 5spd models. (front differential).
• Gear is a 4.44 with an open differential.
• Check for wear since these are older sets and usually not well maintained.

Mazda 79-82 12A: 3.909
Mazda 83-84 12A: 3.933
Mazda 84-85 13B: 4.076
Mazda 85 12A: 3.909
Mazda 86-92 13B 6PI / Turbo 5 speed: 4.10 UK models 4.30
Mazda 1988 Convertible: 3.91
Mazda 1989+ Convertible: 4.10
Mazda 86-92 13B 6PI Automatic: 3.91
Mazda 1989 GTUs 5 speed: 4.30
Mazda 93-95 13B-REW Manual: 4.10
Mazda 93-95 13B-REW Automatic: 3.91
Mazda 09-current 13B Renesis Manual: 4.777
Mazda 09-current 13B Renesis Automatic: 4.3
Mazda 04-08 13B Renesis Manual: 4.44
Mazda Miata 5 speed: 4.10 or 4.30

Kia Sportage 98-02 4x4 (front diff): 4.78
Mazda B2600 87-88 4x4 5spd (front diff): 4.44
Mazda B2600 87-88 4x4 Auto (front diff): 4.10

^^all of the above will direct bolt into the Mazda rear end. All are large spline differentials.

You can use an rx7 pinion seal in a kia sportage third member, its a little different design, but it will fit and so far has worked for me. I will update if any issues arise.

Availible Aftermarket Gears
see Mazdatrix.com for details

1979-1985
4.444 27-110A-M054
4.875 27-110A-1312
5.125 27-1100-1480

1986-1992
86-92 3.91 Non-turbo No Longer Available
86-92 4.30 Non-turbo 27-110A-M066
*86-92 4.875 Non-turbo 27-1100-487C
86-92 4.30 Turbo 27-110B-P092

Also
5.12 and 4.77 Rings and Pinion Sets now available for 86-92 Turbo FC's!!
These are made from the RX8 ring and pinion sets, using your used FC Turbo pinion gear (you must send it in before we can start - we have no cores).

Special order -- takes about four weeks.

Supplied with special rear pinion bearing and special spacer.
Must use the 93-on sleeve #27-171A-R004 (not included with ring and pinion)
5.12 is #27-11FC-5120-TB
4.77 is #27-11FC-4770-TB

1993-1995
3.909 27-110A-P062
4.10 No Longer Avalilble
4.30 27-110A-P0A5
4.44 27-110A-PA28
4.77 27-110A-RS08
5.12 27-110Y-PA28-05

Notes:

• 93-95 pinion is shorter than the 86-92
• Short pinion on Rx2, Rx3SP and 79-85 Rx7
• Long pinion on Rx3

Input Shaft Information

Turbo: 1"x23 Spline (same as some Ford applications)
NA: 1"x22 Spline

[Whizbang]

Limited Slip Information

Q. Where can i get rebuild parts for my OEM Limited Slip?
A. either the dealership or check Mazdatrix.com. The direct link is HERE

Q. What fluid should i use with my limited slip?
A. If it is a clutch type, then use a fluid that had additives for LSD or otherwise indicates it is safe for LSD use. Mostly higher quality fluids fall under this. Also, synthetic fluids is a good choice for any differential.

Mazda Limited Slip Units

Mazda Rx7 83 Clutch Type (GSL models)
Mazda Rx7 12A 84-85 Clutch Type (GSL models)
Mazda Rx7 13B 84-85 Clutch Type (GSL-SE) (Limited Slip is less aggressive than 12A model)

Mazda Rx7 13B 6PI 86-88 Clutch Type (GXL, GTU)
Mazda Rx7 13B Turbo 87-88 Clutch Type (Turbo II)
Mazda Rx7 13B 6PI 89-92 Viscous Type (GTUs)
Mazda Rx7 13B Turbo 89-92 Viscous Type (Turbo II)

Notes:

• 1983 and earlier models do not interchange with 84-85 models. Changes in axle design do not allow the interchange.
• Turbo LSD units do not interchange with Non-Turbo LSD units.

Aftermarket Torsen Limited Slips
see Mazdatrix.com for details

84-92 Non-turbo ------ MZTX-TORSEN1
93-95 Twin Turbo ----- 27-200E-P099

Torsen Limited Slips per Mazdatrix:

These very unique torque sensing differential limited slip units are now available for 84 and later RX-7's. They really are the absolute best design for rear traction under ALL different conditions. It is able to transmit far more torque to the wheel that still has traction than any other type of differential. It uses the friction of the worm gear teeth and the thrust washers for the differential limiting force. In comparison with viscous type, or friction type LSD, it has the following benefits:
1) Large bias ratio torque proportioning
2) Less change of bias ratio over time of car use
3) No special differential oil or LSD additives needed
4) Improved overall traction and improved controllability under acceleration.
5) Virtually no change of torque sensing or traction control through differential temperature range.

Aftermarket "Kaaz" Limited Slips

Cost for Kaaz clutch type limited slip range from about 950 to about 1100 dollars.

WPC coating reduces the "clicking" and "clunking" noises associated with a strong working limited slip.

1.5 Way (Suitable for Road Racing)

• 84-92 N/A -------------------- DBZ1810
• 84-92 N/A WPC COATED ------- DBZ1810-WPC
• 87-88 TURBO ----------------- SBZ1310
• 87-88 TURBO WPC COATED ---- SBZ1310-WPC
• 89-92 TURBO ----------------- SBZ1315
• 89-92 TURBO WPC COATED ---- SBZ1315-WPC

2 Way (Suitable for Drifting / Drag Racing)

• 84-92 N/A -------------------- DBZ1810-2
• 84-92 N/A WPC COATED ------- DBZ1810-WPC-2
• 87-88 TURBO ----------------- SBZ1310-2
• 87-88 TURBO WPC COATED ---- SBZ1310-WPC-2
• 89-92 TURBO ----------------- SBZ1315-2
• 89-92 TURBO WPC COATED ---- SBZ1315-WPC-2

[Whizbang]

Clutch Information

Clutch Diameters

Mazda pre-1982 12A / 13B: 215mm
Mazda 1983-1991 12A / 13B 6PI: 225mm
Mazda 1987-1988 13BT: 235mm
Mazda 1989-1991 13BT: 240mm
Mazda 1993-1995 13B-REW:
Mazda 04-current 13B Renesis: 236mm

***note: the S4 / S5 split has a 5mm difference STOCK. Performance clutches are all 240mm****

Types of Aftermarket Clutches


Flywheel Information

Identifying Flywheels

There are several versions of the OEM flywheel over the years. Each has different diameters, weights and markings.

Weights are approx.

1978-1980 12A--------------30lbs-------None
1981-1982 12A--------------23lbs-------21 **this flywheel is thinner and lighter than the rest and has a different pressure plate requirement**
1983-1985 12A--------------26lbs-------31
1984-1985 13B (GSL-SE)-----26lbs-------N304
1986-1988 Non Turbo 13B----24lbs ------N326
1989-1992 Non Turbo 13B----21lbs-------N350
1987-1988 Turbo 13B--------27lbs-------N318
1989-1992 Turbo 13B--------23lbs-------N370
1993-1995 Turbo 13B--------20lbs-------N3A1

Lightweight (Aftermarket) Flywheels

Aftermarket lightweight flywheels are a modification that is somewhat of a double edged sword. A heavier flywheel, in general terms, provides a smoother ride, better idle quality and an easier start from stop. A lightweight flywheel requires less energy to get moving which translates to move usable power and a faster run through the rpm range. Downsides that this can be reduced idle quality and some shuttering while driving, especially with ported cars. Can also mean more wear on the clutch due to the change in driving experience from a stop.

When buying an aftermarket flywheel, ask your self a few questions:

1. Does the flywheel come with the counterweight?
2. If it does, is it the right weight for what i need?

There quite a number of options for all years of the rotary engine. Some will not provide a counterweight with the flywheel. This is an important component since aftermarket flywheels bolt to the counterweight. Now, just because it may come with a counterweight, doesn't mean its even the weight you need. The counterweight is critical to balancing of the rotating assembly and the wrong counterweight can and will attached to your engine, but will not be the proper one to use. The best thing to do is source your own and personally assure that its the one you need.

Brands of Flywheels

ACT

ACT makes a nice flywheel in two different versions, BUT will only work with the turbo transmission. Also source your counterweight elsewhere since they are not well informed that different years require different weights.

Streetlite

• Part #600145
• 13.9lbs

Prolite

• Part #600140
• 9.8lbs

Fidanza

Fidanza is yet another good option. They do not include the weight of the counterweight in their calculations and require you to source your own counterweight.

Lightweight Steel

• 1987-1995 Turbo 13B Part #261941 18lbs
• 2004+ RENESIS 13B Part #261801 18lbs

Lightweight Aluminum

• 1986-1991 Non Turbo 13B Part #161991 8lbs
• 1987-1995 Turbo 13B Part #161941 10lbs
• 2004+ RENESIS 13B Part #161801 10lbs

Guru



Guru produces a 4140 Chrome Moly flywheel that is probably the top of the line thing you can buy. It uses a 5.5" style AP, Tilton or Quartermaster clutches.

Technical Specifications
Flywheel:

• Flywheel currently delivered for the RX7 Turbo case transmissions
• RX7 Generation 1-3 (Series I-VI)
• Direct fitment within bell-housing with no modifications necessary
• No ring gear as teeth directly cut onto flywheel
• Flywheel heat treated and black oxidised

Clutch:

• Suit AP, Tilton and Quarter Master (QM) 5.5" clutch assemblies
• Delivered with custom thrust bearings & mount as well as gearbox thrust bearing slider nose

Material:

• All component are precision manufactured
• 4140 Chrome Moly
• Heat treated and black oxidised

Guru 4140 Flywheel
10.1 lbs
16lbs

OEM Turbo II
27 lbs
44 lbs

Racing Beat

Racing beat sells an array of flywheels in either steel or aluminum. Their price includes the counterweight specific for your year and model engine!

Lightweight Steel

• 1974-1982 12A Part #11440 16lbs (compared to 30lbs [74-80] / 23lbs [81-82] stock)
• 1983-1985 12A Part #11441 16lbs (compared to 26lbs stock)
• 1984-1985 13B (GSL-SE) Part #11442 16lbs (compared to 23lbs stock)
• Rx-4 and Cosmo 13B Part #11450 16lbs (compared to 30lbs stock)
• 1986-1988 Non Turbo 13B Part #11444 17lbs (compared to 24lbs stock)
• 1989-1992 Non Turbo 13B Part #11447 17lbs (compared to 22lbs stock)
• 1987-1988 Turbo 13B Part #11445 17lbs (compared to 28lbs stock)
• 1989-1995 Turbo 13B Part #11446 17lbs (compared to 22lbs [89-92] / 19lbs [93-95] stock)

Lightweight Aluminum

• 1974-1982 12A Part #11452 12lbs (compared to 30lbs [74-80] / 23lbs [81-82] stock)
• 1983-1985 12A Part #11456 12lbs (compared to 26lbs stock)
• 1984-1985 13B (GSL-SE) Part #11457 12lbs (compared to 23lbs stock)
• Rx-4, REPU and Cosmo 13B part #11453 12lbs (compared to 30lbs stock)
• 1986-1988 Non Turbo 13B Part #11464 12lbs (compared to 24lbs stock)
• 1989-1992 Non Turbo 13B Part #11465 12lbs (compared to 227lbs stock)
• 1987-1988 Turbo 13B Part #11448 12lbs (compared to 28lbs stock)
• 1989-1995 Turbo 13B Part #11449 12lbs (compared to 22lbs [89-92] / 19lbs [93-95] stock)
• 2004+ RENESIS 13B Part #11468 12lbs (compared to 16.8lbs stock)

OS Giken

http://www.osgiken.net/products/supersingle.html


Counterweight Information

Identifying Counterweights

Series 5/6 (1989-1995) 0.498-0.510

Weight of Counterweights
4.0lbs

[Whizbang]

Fluid Types and Capacities

***synthetics are recommended for use in all applications***

Transmissions (manual)
1979-1981 Transmissions: 1.8 qts. (1.7L)
1982-1985 Transmissions: 1.8 qts (1.7L)
1986-1991 Non Turbo Transmissions: 2.1 qts


Transmissions (automatic)
pre 1985 Japco automatic: 7.9 qts. from empty (7.5L)


Differentials
1979-1983 Differentials: 1.25 qts GL-5 SAE 90
1984-1985 Differentials: 1.6 qts GL-5 SAE 90
1986-1991 Non Turbo Differentials (Open): 1.4 qts GL-5 SAE 90
1986-1988 Non Turbo Differentials (Clutch Type LSD): 1.4 qts GL-5 SAE 90 (must have LSD safe additives)
1987-1988 Turbo Differentials (Clutch type LSD): 1.4 qts GL-5 SAE 90 (must have LSD safe additives)
1989-1991 Turbo Differentials (Viscous type LSD): 1.4 qts GL-5 SAE 90

[Whizbang]

Troubleshooting (Manual Transmissions)

Q. Abnormal noise from transmission?
A. Probable causes:
1. Insufficient oil
2. Deterioration of oil quality
3. Worn bearing
4. Wear of sliding surfaces of counter-shaft gear
5. Wear of sliding surfaces of gears
6. Excessive gear backlash
7. Damaged gear teeth

Remedies corresponding to above:
1. Add oil
2. Replace oil
3. Adjust or replace
4. Replace
5. Replace
6. Replace
7. Replace


Q. Difficulty shifting?
A. Probable causes:
1. Bent change rod
2. No grease in transmission control system
3. Insufficient oil
4. Deterioration of oil quality
5. Wear or play of shift fork / rod
6. Wear or poor contact of synchro ring or synchro cone of gear
7. Excessive play in gears
8. Wear of bearing
9. Wear of synchro key
10. Improper disengagement of clutch

Remedies corresponding to above:
1. Replace
2. Add grease
3. Add oil
4. Replace oil
5. Replace
6. Replace
7. Replace
8. Adjust or replace
9. Replace
10. Improper disengagement of clutch


Q. Jump out of gear?
A. Probable causes:
1. Bent change rod
2. Weak / broken lock-ball spring
3. Wear of shift fork
4. Wear of clutch hub or hub sleeve
5. Wear of gear sliding parts
6. Excessive gear backlash
7. Wear of bearing
8. Loose or broken engine / transmission mounts

Remedies corresponding to above:
1. Replace
2. Replace
3. Replace
4. Replace
5. Replace
6. Replace
7. Adjust or replace
8. Fix / Tighten


Q. Gear shift lever difficult / rough?
A. Probable causes:
1. Sticking control rod
2. Malfunction of ball joint on control rod
3. Bent change rod

Remedies corresponding to above:
1. Replace
2. Replace
3. Replace

[Whizbang]

Troubleshooting (Auto Transmissions)

Chart of Inspections (w/o disassembly)
A. ATF quality
B. Range selector linkage
C. Inhibitor switch and wiring
D. Vacuum diaphragm and piping
E. Kickdown solenoid, switch and wiring
F. Engine idling speed
G. Oil Pressure
H. Engine Stall Speed
I. Rear lubrication
J. Control valve
K. Governor valve
L.. Band servo
M. Transmission air check
N. Fluid inspection
O. Ign. switch or start motor
P. Engine adjustment and brake inspection

Chart of Inspections (after disassembly)
1. Rear clutch
2. Front clutch
3. Brake band
4. Low and reverse brake
5. Oil pump
6. Hydraulic circuitry
7. Torque converter one-way clutch
8. Power train one-way clutch
9. Parking gear mechanism
10. Planetary gear


***inspections for probable causes are in order from most likely to least likely***

Q. Engine does not start in "P" or "N"
A. Probable causes: O, B, C

Q. Engine starts in ranges other than "P" or "N"
A. Probable causes: B, C

Q. Excessive "N" to "D" range shift shock
A. Probable causes: F, D, G, J, 1

Q. Vehicle does not move in "D" but does in "1, 2, R"
A. Probable causes: B, G, J, 8

Q. Vehicle does not move in "1, 2, D" but does in "R" / Very poor acceleration
A. Probable causes: A, B, N, G, J, M, P, 1, 6, 2

Q. Vehicle does not move in "R" but does in "1, 2, D" / Very poor acceleration
A. Probable causes: A, B, G, N, J, M, 4, 2, 1, 6

Q. Vehicle does not move in any range
A. Probable causes: A, B, G, N, J, M, 5, 6, 9

Q. Power transmission slippage felt when starting
A. Probable causes: A, B, G, N, J, D, M, 5, 6

Q. Vehicle moves in "N" range
A. Probable causes: B, N, J, 1

Q. Low max. speed / Poor acceleration
A. Probable causes: A, B, N, G, H, L, J, P, 3, 4, 1, 2, 5

Q. Vehicle braked when "R" range selected
A. Probable causes: N, M, L, 1, 3, 9

Q. Excessive creep
A. Probable causes: F

Q. No creep at all
A. Probable causes: A, B, F, N, J, 5, 6, 1, 2

Q. Does not shift from 1st to 2nd gear
A. Probable causes: B, D, E, N, J, K, M, L, 3, 6

Q. Does not shift from 2nd to 3rd gear
A. Probable causes: B, D, E, N, J, K, M, L, 2, 6

Q. Excessively high 1-2, 2-3 shift points
A. Probable causes: D, E, G, N, J, K,

Q. Shift directly from 1 to 3
A. Probable causes: N, J, M, K, 3, 6

Q. Excessive 1-2 shift shock
A. Probable causes: D, H, N, J, L, 3

Q. Excessive 2-3 shift shock
A. Probable causes: D, G, J, M, L, 2

Q. No 1-2 shift shock or slippage
A. Probable causes: A, B, D, G, N, J, M, L, 3, 6

Q. No 2-3 shift shock or slippage / Engine runaway
A. Probable causes: A, B, D, G, N, J, M, L, 2, 6

Q. Vehicle braked when shifted from 1 to 2
A. Probable causes: N, J, 2, 4, 8

Q. Vehicle braked when shifted from 1 to 2
A. Probable causes: N, L, J, 3

Q. Does not shift from 3 to 2
A. Probable causes: D, N, J, K, M, L, 2, 3, 6

Q. Does not shift from 2 to 1 or 3 to 1
A. Probable causes: D, N, J, K, M, L, 3, 8

Q. Shift shock once accelerator is released and vehicle is decelerating
A. Probable causes: B, D, E, G, J, K, 2

Q. Excessively high 3-2, 2-1 shift points
A. Probable causes: B, D, E, G, J, K, 2

Q. Does not kickdown in 3 within kickdown limit
A. Probable causes: E, D, N, J, K, 3, 6

Q. Abnormal rise of engine speed and/or kickdown in 3 outside kickdown limit
A. Probable causes: B, D, G, N, J, K, M, 2, 6

Q. Engine runaway or slippage from 3 to 2
A. Probable causes: D, G, N, J, M, L, 2, 3, 6

Q. Does not shift from 3-2, with "D" to "2" range shift
A. Probable causes: B, G, N, J, L, 3, 6

Q. Shifts from 2-1 or 2-3 in "2" range
A. Probable causes: B, G, J

Q. No shift shock / Engine runaway in "1" to "2" range shift
A. Probable causes: A, B, D, F, N, J, M, H, 3, 5

Q. No 3-2 shift in "3" to "2" range shift
A. Probable causes: B, G, N, J, K, M, L, 2, 3, 6

Q. No engine braking in "1" range
A. Probable causes: B, G, N, J, M, 4, 6

Q. Shifts from 1-2 or 2-3 in "1" range
A. Probable causes: B, J, 6

Q. Does not shift from 2-1 in "1" range
A. Probable causes: A, B, N, J, K, L, M, 4, 6

Q. Excessively large 2-1 shift shock in "1" range
A. Probable causes: D, H, N, J, 4

Q. vehicle moves in "P" and/or parking gear not disengaged when "P" range is disengaged
A. Probable causes: B, 9

Q. Transmission overheats
A. Probable causes: A, I, G, H, N, J, M, L, 2, 3, 4, 5, 6, 7, 10

Q. Oil emission and/or white smoke while running
A. Probable causes: A, I, D, N, G, H, J, M, 2, 3, 4, 5, 6, 7, 10

Q. Abnormal odor from oil charging pipes
A. Probable causes: A, N, 1, 2, 3, 4, 5, 6, 7, 10

Q. Transmission noisy in "P" and "N" ranges
A. Probable causes: A, G, 5

Q. Transmission noisy in "D", "1", "2" and "R"
A. Probable causes: A, G, 1, 5, 8, 10

[Whizbang]

reserved

[Whizbang]

Rally and Rallycross

I am not including any information on this section for the FD as i have never heard of an FD participating in rallying. Whereas i have seen at least on Rx8 compete, it is still an off the wall concept and not to be covered here.

FB Transmissions and Differentials

The FB rear axle is as you may know, a solid axle design. A few things to consider:

• Strengthening of axle housing
• Retention or modification of suspension geometry.
• Reinforcing of suspension mounting points.

The best choice is the 84-85 axle due to the stronger design and lends itself to be the most resistance to deformation.

As far as the differential goes, there are a few other considerations:

• An open differential is essentially unusable
• A welded differential is a cheap option but may have some issues with how the car performances. One large advantage is that if an axle does break, the other can still get you back.
• A clutch type differential is
• A viscous type is not preferred due to overheating issues and a weaker design.
• A torsen type is not preferred due to overheating issues and a weather design.

FC Transmissions and Differentials

The FC presents an entirely different suspension design. The most important differences is the use of an Independent Rear Suspension (IRS) and the use of Strut / Springs in all corners of the chassis.

What does this mean for you?

• Ability to use a better design of rally damper assembly both front and rear.
• Existance of the very durable turbo model drive line parts. Especially in regards to the transmission and differential.
• There is some debate as to if IRS is better or worse than a solid axle. I may try to cover this in detail later.

As far as the differential goes, there are a few other considerations:

• An open differential is essentially unusable
• A welded differential is a cheap option but may have some issues with how the car performances. One large advantage is that if an axle does break, the other can still get you back.
• A clutch type differential is
• A viscous type is not preferred due to overheating issues and a weaker design.
• A torsen type is not preferred due to overheating issues and a weather design.

[Kentetsu]

Very well done man! Nice to have all of this information in one place.

[vex]

Specific for FC: Can the TurboII transmission aftermarket internals be swapped into the Naturally aspirated transmission case?

[Whizbang]

Originally Posted by vex

Specific for FC: Can the TurboII transmission aftermarket internals be swapped into the Naturally aspirated transmission case?

For everything i know about the two transmissions, i dont believe its possible. The "R" type transmission used in the Turbo II has some considerable differences in construction than the smooth case transmissions. So i would have to lean towards a "no" in general. BUT since i have no first hand knowledge i wouldn't rule out a chance that some individual parts might work.

[vex]

Originally Posted by Low Impedance

For everything i know about the two transmissions, i dont believe its possible. The "R" type transmission used in the Turbo II has some considerable differences in construction than the smooth case transmissions. So i would have to lean towards a "no" in general. BUT since i have no first hand knowledge i wouldn't rule out a chance that some individual parts might work.

I think this might be a good article/write up if we can get the measurements of a turbo II internals and the NA internals.

[Whizbang]

i might look into it come this spring after i get a house.

[vex]

Originally Posted by Low Impedance

i might look into it come this spring after i get a house.

The more I think about it the more it just seems like it's the input and output shaft lengths are different. I know we won't know for sure, but I checked the FSM and they didn't mention any dimensions besides just max deflection of the shafts.

What's your take on it?

[Whizbang]

well the whole R type transmission is longer by a couple inches, so its very possible. Plus consider the removable bell housing the smooth case transmissions have. There is plenty of places that differences can occur. I have been thinking about rebuilding my TII trans eventually. I might get down into it and take some measurements. Smooth case trannys are nearly free so when i get one of those ill do the same