1985-1986 Mk I Automatic to Manual Transmission Swap

The auto MR2 has almost all the attachment points for the conversion already in place. All you have to drill is two holes to mount the clutch pedal bracket and the larger hole for the master cylinder. Fortunately, one of the two panels that make up the firewall already has the master cylinder hole punched out. You just have to drill out the second panel to the same diameter.
You need to do a little rewiring to connect the back up light and bypass the start-in-neutral/park wiring used in the auto transmission. I strongly recommend that you take the parts off a parts car or remove the parts yourself from a pick-your-own-parts place. It’s difficult for me to describe how to install the hydraulic lines. You have to do it yourself to figure out how to remove them (and replace them on your car) without unbolting and removing a lot of other components. There are four sections of hydraulic lines. The line that connects to the master cylinder and the long section that travels beneath the car take a lot of manipulation to install.

1. Disconnect and remove battery.

2. Remove spare tire, spare tire support tubing (10 mm bolts) steel hoop and plastic that covers the hydraulic lines in front trunk.
3. Drain antifreeze.
4. Drain transmission fluid (optional).
5. Remove driver’s seat.
6. Remove steering wheel (one screw holds the center section to the wheel and a 17 mm nut holds the steering wheel to the steering column)
7. Remove paneling beneath steering wheel and triangular panel next to door hinge.
8. Loosen rear wheel nuts.
9. Place car on jack stands (? inches) The higher the better, but remember that you have to work on the car from the top and the bottom.
10. Remove brake pedal and install pedal from the manual transmission car (hard to do because of limited access)
11. Drill three holes through fire wall (2 for the mounting bracket, one large one for the master cylinder).
12. Install clutch pedal and mounting bracket (two nuts and one bolt 12 mm?) (hard to do because of limited access)
a. Electrical connection? (Cruise control switch/starter switch – I didn’t hook mine up because I don’t use the cruise control).
13. Install master cylinder.
14. Connect master cylinder to clutch pedal.
15. Install short metal hydraulic line (with rubber seal and fittings) (hard).
a. Disconnect bracket for air conditioning tubing
b. Disconnect hydraulic brake line (top to front left brake)
c. “90 degree” connector for hydraulic lines (10 mm bolt)
16. Remove front suspension bracket
17. Remove plastic covers beneath car
18. Install the long metal hydraulic line (hard)
a. Unbolt water line bracket
b. Unbolt air conditioner line bracket
c. Remove brake line bracket
d. Remove cross bracket under car
e. Support gas tank with a floor jack
f. Unbolt clips holding the brake line (10 mm)
g. Remove cotter pins holding gas tank
h. Start long hydraulic line at the front near the left suspension (tape up ends of the lines to protect the threads.
i. Gently bend/bow line downward at the center to create enough clearance for the line to rear frame member and rear portion of gas tank.
19. Reconnect clips that hold the brake and clutch lines.
20. Connect hydraulic line to “90 degree” connector.
21. Reattach water and air conditioner brackets.
22. Replace gas tank cotter pins, tighten bolts holding brackets
23. Reattach brake brackets
24. Replace two middle plastic shielding (leave last section off)
25. Remove Automatic shift cable bracket
26. Remove center console and rear cubbyholes
27. Remove four plastic plug holding carpet behind seats
28. Remove bracket that supports center console rear trays and hold down carpet.
29. Unbolt shift lever bracket.
30. Unplug electrical connector.
31. Unbolt plastic shielding on engine side of firewall (10 mm nut, 10 mm bolt, 10 mm screw)
32. Disconnect shifter cable from transmission.
33. Unbolt metal cap (two 10 mm bolts) bolted to firewall.
34. Pull rubber seal towards engine compartment.
35. Push out shifter cable and rubber seal into driver compartment.
36. Remove exhaust system
a. Unbolt three nuts that bolts the exhaust manifold to flexible downpipe
b. Unbolt two bolts holding exhaust assembly
c. Unbolt two bolts holding muffler near tailpipe
d. Push exhaust assembly towards left rear to detach from the car

37. Install left drive shaft and Right drive shaft
a. Remove rear wheels
b. Remove 10 mm nuts holding drive shafts to transmission
c. Remove cotter pins from nuts on end of drive shaft
d. Remove serrated cap
e. Remove drive shaft nut (30 mm)
f. Wire drive shaft upwards out of the way
g. With a rubber mallet, tap on drive shaft ends to remove the drive shafts

38. Remove Air Intake and AFM

39. Emission controls removal
a. Remove thermostat body

40. Unbolt transmission from engine
a. Use two floor jacks; one under engine pan and one under the transmission

41. Unplug electrical connecters to transmission

42. Unbolt the three transmission mounts

43. Lower Transmission/engine
a. The transmission should separate and slide off (Be careful! the auto transmission is heavy)
b. Unbolt starter gear and other items used for the auto transmission

44. Install flywheel, clutch, and pressure plate
a. flywheel and (new) bolts
b. clutch plate (new)
c. pressure plate (new) and bolts
d. throw-out bearing (new)

45. Install manual transmission

46. Install rear Transmission/frame rubber mount (new)

47. Seal transmission fluid cooler lines. There are two lines from the cooling system to the automatic transmission that can be plugged.

48. Install slave cylinder and bracket
a. slave cylinder
b. short flexible hydraulic line
c. two short metal hydraulic lines (from flexible line to slave
cylinder/slave cylinder to bleeder)

49. Electrical connections
a. rewire cruise control
b. wire clutch start switch
c. rewire backup light

50. Install manual shift system
a. Sifter plus bracket
b. shift knob
c. two shifter cables
d. shift boot
e. center console

51. Remove and replace combination meter (instrument panel)
a. Remove steering wheel hub (one screw)
b. Remove steering wheel (17 mm nut)
c. Remove triangular panel near dead pedal (10 mm nut)
d. Unscrew hood release latch (screw)
e. Remove lower panel beneath steering wheel (unplug mirror switch)
f. Remove headlight and wiper levers and unscrew aluminum nuts (17 mm?)
g. Remove screws to combination meter frame
h. Remove top cover
i. Slowly pull frame away from meter and carefully unplug connectors
Unscrew ___
Wiper indicator light
Door open indicator light (hardest to remove)
j. Unplug speedometer cable
k. Unplug the three electrical connectors
l. Unplug ECT switch

52. Remove A/T ECU and replace with M/T ECU (Optional as the A/T ECU will work for the manual transmission)

53. Refill fluids (coolant, transmission, etc.)

54. Replace battery and hook up power

This is how I rewired a 1986 AT engine bay harness. I used connectors to preserve the wiring just in case I wanted to convert back to the automatic transmission.

This documentation in no way replaces the Toyota MR2 Repair Manuals. The purpose of this content is only to provide supplementary information to fellow MR2 enthusiasts. Midship Runabout and its contributing authors will not be held responsible for any injury or damages that may occur as the result of practicing any of the methods or procedures described within this website. Article and photo submissions are property of the contributing author.

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