Transmissions

Due to the lack of rebuildable cores, high total price of all the parts needed, never getting ALL the correct parts ordered, and terminal back order problems, we no longer offer rebuilt transmissions. All we can recommend is that you attempt to find a reputable local rebuilder.

Due to the many parts in each of the various available transmissions, and the many updated/part number supersessions etc., we do not offer internal transmission parts.

The following is for information purposes only:

Mazda has given us a large selection of interchangeability of transmissions by keeping the bellhousing bolt pattern, pilot bearing diameter, and clutch spline the same for all rotaries since 1974 (except the 86 and later Turbo).

A discussion of the good points and bad points of specific transmissions will be of more benefit than full listing of the large quantities of parts in each transmission.

All RX-2, 3, 4, Cosmo, and Rotary Pick-ups from 1974 thru 1978 (obviously except automatics) had 4 or 5-speed transmissions that we call "Ribcases". These transmissions had strengthening ribs around the main case, a removable bellhousing, and a large inspection/assembly plate that mounted on the bottom. We have found at least seven different variations in these in bearing diameters, shaft design, shift fork/slider hub design, and shift rod/shift fork assembly design. At least two of these appear to have been available in Japan only, as the parts necessary to rebuild them do not exist in the U.S. parts computers/microfiche/parts supply network. The 12A Ribcase 5-speed is almost impossible to distinguish from the 13B 5-speed. The latter of these was the strongest transmission available until the 86 Turbo.

All these transmissions are interchangeable through 1980 RX-7's. Watch for mixing shift levers/shift towers/switches etc., but all the important dimensions are the same.

For the RX-7 in 1979, Mazda introduced what we refer to as a "Smooth Case" in 4 or 5-speed configuration. These transmissions have virtually no ribbing on the outside, the bellhousing is integral with the main case, and the removable inspection plate is gone. These transmissions, with adequate maintenance and very little abuse, seem to work quite fine. They do wear out eventually and should be replaced when necessary (see Transmission/Differential Trouble Shooting).

For 1981 thru 83 the shifter was made "Remote" and moved back approximately two inches. There were internal changes made also, and we seem to have fewer complaints about these. (But remember they are at least 2 years newer than any 79 or 80). They will bolt into earlier cars, but the tunnel shifter hole needs to be trimmed back, and you're on your own for fitting shifter boots and consoles.

1984 thru 1985 were essentially the same as above except a vent was cast into the right side of the bellhousing.

For 1986 thru 1988 (non-turbo) the rear mount location and design was changed. The torque and horsepower of the 13B six-port, coupled with the weight of the 86+ models appears to be approaching the design limit of the transmission. We have heard of some being replaced before 10k miles, and we have replaced/rebuilt more than a few ourselves. Adequate maintenance and lack of abuse appear to definitely be linked to longevity.

With the introduction of the Turbo in 1986, Mazda added a much beefier transmission. This transmission is patterned after the early "Ribcase" 13B 5-speed, and appears to be excellent, but they made it difficult to install in other models. The bellhousing diameter (not the bolt pattern) is larger, the flywheel is larger, the starter is different and mounts further out, and the driveshaft yoke is larger. It can be installed in other cars (we've done a few) but it is not a "Bolt-In".

Miata 5-Speed gear sets can be installed in 81-92 Non-turbo transmissions with minimal modifications (see Miata Input Shaft Modification) for input shaft mod specs). The stock Miata ratios are considerably nicer than OEM RX7ones -- for street driving or even a "wide ratio" road racing transmission.

Stock Transmission Ratios
Application 1st 2nd 3rd 4th 5th 6th
74-76 RX2, 3, 4, Cosmo, P/U 3.683 2.263 1.397 1.00 .862  
77-78 RX3SP, 4, Cosmo 3.380 2.002 1.390 1.00 .791  
79-80 RX7 3.674 2.217 1.432 1.00 .825  
81-83 RX7 3.674 2.217 1.432 1.00 .825  
84-85 RX7 12a 3.622 2.186 1.419 1.00 .758  
84-85 13b GSLSE 3.622 2.186 1.419 1.00 .807  
1986 RX7 Non-Turbo 3.475 2.002 1.366 1.00 .711  
87-88 RX7 Non-Turbo 3.475 2.002 1.366 1.00 .697  
89-92 Non-Turbo w/o LSD 3.475 2.002 1.366 1.00 .697  
89-92 Non-Turbo with LSD 3.475 2.002 1.366 1.00 .756  
86-88 RX7 Turbo 3.483 2.015 1.391 1.00 .762  
89-95 RX7 Turbo 3.483 2.015 1.391 1.00 .719  
Miata 5-Speed 3.13 1.833 1.303 1.00 .814  
93-95 RX7 Turbo 3.483 2.015 1.391 1.00 .719  
04-08 RX8 3.76 2.269 1.645 1.187 1.00 .843
99- Miata 3.76 2.269 1.645 1.257 1.00 .843
09- RX8 3.815 2.260 1.640 1.177 1.00 .843


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