I started with the Celica S53 lifted out of my car and drained of oil, the MR2 S54 and its starter motor. To enable the repositioning of the starter motor, there is a plate that sits between the flywheel and the engine block that closes off the exhaust-side position of the S53 starter motor, which you will need if you intend to use this gearbox on the first generation 3S-GE engine.
Examining the S53 and S54 gearboxes side by side, the similarities in the casting will immediately leap out at you. The bolts mounting the S53 shift lever and selecting bell crank correspond directly with bolt holes cast into the S54. Remembering that these two gearboxes are mechanically identical, aside from moving over the exterior clutch and sensor components, the most obvious requirement is moving that shift lever and selecting bell crank from the south side of the S54 to the north side, so it can interface with the Celica's shift cables.
Imagine sitting in the driver seat of an MR2 with the engine positioned behind you, the shortest distance between the gear stick and the gearbox is on its south side. Both the Celica and the MR2 drive in the same direction, so if you are sitting in the front seat of the Celica, the shortest path between the gearstick and the gearbox is now meeting on the north side. This is how the shift levers are positioned.
Follow me now as we go step by step!
For reference, see the exploded diagram of the MR2 S54 gearbox. So we're all on the same page, all part names referred to will be the ones used on this page.
This gearbox will be going back into a Celica, so transfer any Celica ancillaries from the S53 to the S54. This includes the slave cylinder lines and brackets, as well as the north engine mount.
Position the gearbox in neutral. Remove the shift lever and selecting bell crank from the S53 by undoing the two 14mm bolts connecting it to the S53. You may need to undo the east engine mount to access these bolts, depending on your tools. I recommend turning the gearbox bell housing face down and attacking these 14mm bolts with vertical leverage. Make sure your drive shafts are plugged up, or you'll start leaking any gearbox oil left in the gearbox.
Undo the no.1 lock ball on the top of the gearbox. Now undo the fat 22mm (if memory serves) hex hub on the control shaft cover. Your shift and select lever assembly will now slide out from the gearbox. Place aside with the previously removed shift lever and selecting bell crank.
S53 Shift and Select lever Assembly, protected by your Mum's pyjamas.
Moving now onto the S54 gearbox, to remove the shift and select lever assembly we must first remove the selecting bell crank and shift lever mounted on the south side of the shaft. The lever is held on by a pin through the shaft of the select assembly. Instructions say to strike the pin with a hammer to dislodge the pin, but I had no luck. I am keen to hear if anyone has more info on this.
Shift Lever holding the Shift and Select lever Assembly in position.
Not required for our new application, I decided the easiest way past this obstacle was to use an angle grinder to cut through the shaft just before the shift lever. I've never used an angle grinder before, but it cost me $19 to hire from Kennard’s and 10 minutes to cut through. Remove the rubber dust boot to expose the best place to cut through.
Remove this rubber boot to get clear access to the shaft for your "modifying".
Undo the control shaft cover and its monstrous 22mm bolt pattern and the no.1 lock ball as with the S53. Now that we're free from the MR2's shift lever, the shift and select lever assembly will pull smoothly through the now gaping maw.
Exposed Shift and Select lever Assemby for removal.
Insert the S53 shift and select lever assembly into the S54, studying the casting and the protrusions inside the shaft to ensure a smooth entry. It may take a few twists and rotations to see into its place.
Reinsert the no.1 lock ball, but not so tight that the gears can't shift. Re-do the control shaft cover 22mm hub and attach the selecting bell crank from the S53 onto the S54 gearbox following the procedures used previously if the engine mount poses an obstacle.
Test the shift functions of the gearbox by moving through the gears and if you are satisfied, the gearbox is now ready to refill with oil and remount.
Pillaged Celica S53.
Parts that I didn't need. Don't be afraid to break these.
Completed FWD-ready S54
Open hole in casing, currently seeking a solution to plug.
Bookmarks