I'm swapping Transmission in my 1980 RX-7. My question is has anyone ever put an 81-85 Trans. In a 1980. If so what are the basic steps other than cut a new hole for the later gear box. Also I noticed that when I removed my box there are 3 boots that go over the base of the shifter are they really nessecary??
1980 RX-7 Transmission Swap
- Thread starter Weaver7
- Start date
****Copied info****
Transmission - Bolt-Pattern
All Mazda rotaries from US model year 1974 on are equipped with the same bolt pattern. All such transmissions can be bolted to all such engines. The large-clutch flywheels used on turbo models will prevent NA transmissions from being installed, but with no flywheel installed, an NA transmission will bolt up.
Transmission - Length 2002/11/27
All North American spec Mazda rotary manual transmissions from 1974 through 1991 are the same length (~32") from the tip of the input shaft to the tip of the output shaft, with the possible exception of the 1974 RX-2, which may be around 40 mm shorter. Bellhousing and input shaft were shortened for 1993-up models.
Transmission - Suitability
Group 1
1974 through RX-7 SA/Series 1 (((SA is 1979 & 1980)))
Simple functional equivalent bolt-in:
RX-3 1976-8 5-speed
RX-4 1976-8 5-speed
REPU 1976-8 5-speed
Cosmo 1976-8 5-speed
RX-7 1979-80 5-speed, 4-speed
Comments:
These 4-speeds have the same length, bolt pattern, and shifter location as the later 5-speeds, but the mount pad is slightly forward.
RX-2 1974 (maybe, see below)
RX-3 1974-5
RX-4 1974-5
REPU 1974-5
Group 2 boxes can be substituted into cars in this group if console modifications are made.
1974 RX-2 transmissions may be identical to 1974-5 RX-3 & RX-4s. If not, the difference would be a shorter overall length. Pre-1974 RX-2 transmissions were shorter than the earlier RX-3 transmissions, which were the same length as this group.
Late production 1980 boxes can have the tailhousing and entire shift mechanism from Group 2 or 3 boxes installed for use in Group 2 or 3 cars. The 1980 boxes that have this compatibility are distinguished by their use roll pins instead of cap screws to mount shift forks and fingers to their rails.
Group 2
RX-7 FB/Series 2 & 3 (((FB is 1981 through 1985)))
Simple functional equivalent bolt-in
1981-3 5-speed
1984-5 12A 5-speed
1984-5 13B 5-speed
Comments:
1981-3 ratios and other details are all identical
Several 1984-5 internal basics, including ratios, are different from earlier boxes. SE boxes used two different 5th gear ratios, both of which were taller than 12A boxes. There were also a few running changes in internal design details.
SE boxes are easily distinguishable externally by two large air vents cast into both sides of the bell housing.
These boxes can have the shift mechanism from Group 3 boxes installed for use in Group 3 cars. The expedient way to do this is a complete tailhousing swap.
These boxes can have the tailhousing and complete shift mechanism from late 1980 boxes installed for use in Group 1 cars.
Group 3
RX-7 FC/Series 4 & 5 NA
Simple functional equivalent bolt-in
1986-91 5-speed
Comments:
Basic design of these boxes is identical to the last Group 2 boxes.
1-4 ratios are identical for all years, but different from the latest Group 2 boxes.
5ths differed by model and year.
These boxes can have the shift mechanism from Group 2 boxes installed for use in Group 2 cars. The expedient way to do this is a complete tailhousing swap.
Group 4
RX-7 FC/Series 4 & 5 Turbo
Simple functional equivalent bolt-in
1987-91 5-speed
Comments:
These boxes are derived from the much stronger pre-RX-7 rotary boxes. Synchronizer design was significantly improved, and the output shaft size was increased, requiring a larger driveshaft yoke.
Turbo models use larger clutches and flywheels and a different starter than NA models.
Bellhousings from the pre-1979 boxes can be substituted for use with NA starters, flywheels and clutches, partially easing their use in 1st gen cars. Sales volume from 1974-78 was sufficient that finding a used such transmission to cannibalize should not require heroic talent. The other obstacle to their use in 1st gen cars is the shifter location much farther rearward. Solving this latter problem requires some clever shifter reengineering (possibly using a portion of the original transmission's shift mechanism) or a hatchet job on the console.
Ford used a variant of this transmission in some of its products in the 1980s.*****
Weaver7, hope the info is of value. With reference to your question of the three boots keep them all. If there is any kind of nasty stuff under the car the three boots will keep it out. Oil, smoke, rain water, dust/dirt & who knows what.
Have Fun
David
Transmission - Bolt-Pattern
All Mazda rotaries from US model year 1974 on are equipped with the same bolt pattern. All such transmissions can be bolted to all such engines. The large-clutch flywheels used on turbo models will prevent NA transmissions from being installed, but with no flywheel installed, an NA transmission will bolt up.
Transmission - Length 2002/11/27
All North American spec Mazda rotary manual transmissions from 1974 through 1991 are the same length (~32") from the tip of the input shaft to the tip of the output shaft, with the possible exception of the 1974 RX-2, which may be around 40 mm shorter. Bellhousing and input shaft were shortened for 1993-up models.
Transmission - Suitability
Group 1
1974 through RX-7 SA/Series 1 (((SA is 1979 & 1980)))
Simple functional equivalent bolt-in:
RX-3 1976-8 5-speed
RX-4 1976-8 5-speed
REPU 1976-8 5-speed
Cosmo 1976-8 5-speed
RX-7 1979-80 5-speed, 4-speed
Comments:
These 4-speeds have the same length, bolt pattern, and shifter location as the later 5-speeds, but the mount pad is slightly forward.
RX-2 1974 (maybe, see below)
RX-3 1974-5
RX-4 1974-5
REPU 1974-5
Group 2 boxes can be substituted into cars in this group if console modifications are made.
1974 RX-2 transmissions may be identical to 1974-5 RX-3 & RX-4s. If not, the difference would be a shorter overall length. Pre-1974 RX-2 transmissions were shorter than the earlier RX-3 transmissions, which were the same length as this group.
Late production 1980 boxes can have the tailhousing and entire shift mechanism from Group 2 or 3 boxes installed for use in Group 2 or 3 cars. The 1980 boxes that have this compatibility are distinguished by their use roll pins instead of cap screws to mount shift forks and fingers to their rails.
Group 2
RX-7 FB/Series 2 & 3 (((FB is 1981 through 1985)))
Simple functional equivalent bolt-in
1981-3 5-speed
1984-5 12A 5-speed
1984-5 13B 5-speed
Comments:
1981-3 ratios and other details are all identical
Several 1984-5 internal basics, including ratios, are different from earlier boxes. SE boxes used two different 5th gear ratios, both of which were taller than 12A boxes. There were also a few running changes in internal design details.
SE boxes are easily distinguishable externally by two large air vents cast into both sides of the bell housing.
These boxes can have the shift mechanism from Group 3 boxes installed for use in Group 3 cars. The expedient way to do this is a complete tailhousing swap.
These boxes can have the tailhousing and complete shift mechanism from late 1980 boxes installed for use in Group 1 cars.
Group 3
RX-7 FC/Series 4 & 5 NA
Simple functional equivalent bolt-in
1986-91 5-speed
Comments:
Basic design of these boxes is identical to the last Group 2 boxes.
1-4 ratios are identical for all years, but different from the latest Group 2 boxes.
5ths differed by model and year.
These boxes can have the shift mechanism from Group 2 boxes installed for use in Group 2 cars. The expedient way to do this is a complete tailhousing swap.
Group 4
RX-7 FC/Series 4 & 5 Turbo
Simple functional equivalent bolt-in
1987-91 5-speed
Comments:
These boxes are derived from the much stronger pre-RX-7 rotary boxes. Synchronizer design was significantly improved, and the output shaft size was increased, requiring a larger driveshaft yoke.
Turbo models use larger clutches and flywheels and a different starter than NA models.
Bellhousings from the pre-1979 boxes can be substituted for use with NA starters, flywheels and clutches, partially easing their use in 1st gen cars. Sales volume from 1974-78 was sufficient that finding a used such transmission to cannibalize should not require heroic talent. The other obstacle to their use in 1st gen cars is the shifter location much farther rearward. Solving this latter problem requires some clever shifter reengineering (possibly using a portion of the original transmission's shift mechanism) or a hatchet job on the console.
Ford used a variant of this transmission in some of its products in the 1980s.*****
Weaver7, hope the info is of value. With reference to your question of the three boots keep them all. If there is any kind of nasty stuff under the car the three boots will keep it out. Oil, smoke, rain water, dust/dirt & who knows what.
Have Fun
David
JoeColeman
New member
I helped a buddy put a '85 tranny into his '80. We had to swap the '80 tailshaft onto the '85 tranny. The forks that the shifter engages were also different. If yours is a late '80 car, they will be the same, if not, late '80 forks can be purchased from Mazda Motorsports. We used forks from a '79 Mazda B2000 tranny I had.
lateapex911
Super Moderator
I wonder what the legality of cutting the tunnel to fit the later tranny is?
Does IITDSYCYC apply here?
------------------
Jake Gulick
CarriageHouse Motorsports
ITA 57 RX-7
New England Region
[email protected]
Does IITDSYCYC apply here?
------------------
Jake Gulick
CarriageHouse Motorsports
ITA 57 RX-7
New England Region
[email protected]
jduncan569
New member
Friend of Joe checking in. Weaver7, what is the last 6 of your vin? If it is lower than 586xxx (IIRC) than you will be screwed in the same boat that I was. I am opposed to hacking up my tunnel too, so I wanted to retain the stock shifter location. If your vin is after the above number than you have it easy. Simply remove the tailhousing from the outgoing 80 tranny. If the fingers on the shift forks are held in place by a 10mm bolt, then you will require additional parts to complete the swap of your fb tranny. If they are held on by roll pins, then all you have to do is remove the fingers and install them on the new transmission with the 80's tailhousing/shifter.
If your tranny is the bolted finger types, you will need the following parts (prices are from MazdaMotorsports in June of this year)
8562-17-402 1.00 14.75 1-2 SHIFT FORK
8562-17-404 1.00 13.20 3-4 SHIFT FORK
8134-17-406A 1.00 29.65 R SHIFT FORK
9922-20-522 1.00 0.95 PIN, SPRING
You also may need to replace the roll pins if you get a little too carried away when removing them. I was able to reuse the ones from my donor tranny. With these fingers and the 80 tailshaft/shifter, you will be back in business.
As a side note, while the 79 B2000 fingers worked as a temp fix, the parts above are what you actually need to do it right. The B2000 parts do not allow 5th and Reverse use. Boo.
If your tranny is the bolted finger types, you will need the following parts (prices are from MazdaMotorsports in June of this year)
8562-17-402 1.00 14.75 1-2 SHIFT FORK
8562-17-404 1.00 13.20 3-4 SHIFT FORK
8134-17-406A 1.00 29.65 R SHIFT FORK
9922-20-522 1.00 0.95 PIN, SPRING
You also may need to replace the roll pins if you get a little too carried away when removing them. I was able to reuse the ones from my donor tranny. With these fingers and the 80 tailshaft/shifter, you will be back in business.
As a side note, while the 79 B2000 fingers worked as a temp fix, the parts above are what you actually need to do it right. The B2000 parts do not allow 5th and Reverse use. Boo.