Thanks to my.is member Dark2JZ for this tutorial on changing the clutch.
OK, let's hit it. and BTW, if you want to install headers, a y-pipe, or a short shifter, now would be the best time to do it. It's all gotta come out to remove the tranny.
How to install a clutch in a 02-05 IS300 with W55 or W58 manual transmission.
While your hands are clean, let's start by tearing apart the interior. You have to remove the center console to remove the shifter. The armrest has two bolts held in behind the circular discs on each side of the swivel of the armrest. Remove these, as well as the felt pad in the bottom of the center console. Unscrew the shift knob, and snatch up on the shift boot. It should come up enough to unhook the electrical connectors under the boot plate. Then remove the boot plate. The e-brake boot snatches up as well. nothing serious. Slide the seats all the way back, and you will see plastic caps covering two side screws. Pop them off, and remove the side screws, as well as the two screws that were under the shift boot plate and the two screws under that little felt pad in the console. Now you can tilt up the back of the console, unhook the 12v connector, and remove the console. Unbolt the shifter plate and slide the rubber boot off the shift lever. now remove the 4 bolts holding the shifter to the tranny, and pull straight up, noting the position of the shift lever, preferably in neutral.
Now, pop the hood, and start some prep work. unhook the negative battery terminal, remove the intake tube and engine cover (if you still use this abomination), and unbolt the two radiator hold-down hooks. Disconnect the 3 O2 sensor harnesses, being careful not to break any of them. Now, soak all the exhaust bolts in penetrating oil, and remove all the nuts that hold the exhaust manifold (header) to the block, with the exception of two, so the exhaust will not bang around on you while you remove it. Bravo.
Under the car
Now, make sure the car is firmly supported on a vehicle lift, or a good, sturdy set of jackstands (lift is HIGHLY preferred. Doing this crap on your back is not how you really wanna do this.) Remove all the plastic underbody panels. They are held in with nothing more than 10mm screws and pop-clips. Spray the y-pipe's O2 sensor lightly with penetrating oil, and CAREFULLY remove it. These things strip out and round off easily, so be easy and slow. Now, spray all the exhaust hardware with penetrating oil, and remove the y-pipe and exhaust midpipe. At this point, you can remove the two nuts that are supporting the exhaust manifold, and get that huge thing out of the way. It's a wrestling match to get it out, but be patient, and don't force anything. It will come out. Now, you can remove the driveshaft... and bring some ass because those 14mm bolts and nuts that hold the shaft to the diff are tighter than hell. I was using the double-wrench trick, and they were still a bitch and a half. Once you get them all out, DO NOT let the shaft fall!!!! It is carefully balanced, and the u-joints rarely get any movement, so it is best to keep it as straight as possible to keep the shaft in perfect balance. A hard bang as the two-peice shaft bends can damage the u-joints. And the shaft is held in with a center-support bearing that is held to the car with a pair of 14mm bolts. These bolts have aluminum spacers that go between the body and the center support bearing. REMEMBER THESE SPACERS, or you will get a VERY bad vibration when you reinstall the shaft.
Now, remove the wiring connectors and ground wire on the tranny, unbolt the clutch slave cylinder from the tranny, and drain the tranny oil. It will come rushing out the tailhousing if you do not drain it. Not fun. Unbolt the aluminum tranny crossmember, and let the tranny hang. Now, here's were it gets interesting, and alot of people will debate on what's the easiest method. I used this way, but you can fight as much as you want with other methods. No sweat off my brow. I LOOSENED the engine mount bolts as well as the engine cradle bolts. I did not remove them, but I did screw them down to the point where I couldn't see the threads of the bolts, so the engine cradle was about 3/4th of an inch lower, and the engine was free to wobble back and forth on the motor mounts. Now, slowly and gently jack up on the crank pulley of the motor, watching and listening for any bad noises. You want to jack up until you can see the heads of the top bellhousing bolts from underneath the car. Here's where the fun begins. With the engine mounts as loose as can be, and the engine cradle lowered about 3/4 of an inch, everything SHOULD be easy to reach and remove with a 3-5 foot extension. If not, check you clearances. Something is binding or caught. Now, remove the bellhousing bolts, and carefully manhandle the tranny out.
Now that everything is apart, look for rear main seal leaks, tranny leaks, clutch condition, throwout bearing, and dual-mass flywheel. the flywheel's internal springs should still be stiff and extremely hard to move. If you can slide the friction surface back and forth with ease (like, your fingers effort), then you should replace the flywheel (UPGRADE TIME!!!!!) Also, you will need to remove the pilot bearing in the crankshaft. It's gonna require a very small, specialized slide hammer. I used one for a GM, and just used one hook on it's two-hook setup.
Drive in the new pilot bushing with an equal-sized deep-well socket until it sits bottomed-out in the crankshaft. If you decide you want to replace the flywheel, the flywheel-to-crankshaft bolts should be torqued to 82ft-lbs in a criss-cross fashion. Now, install your new clutch disc with the supplied disc alignment tool, then lay on the clutch cover with the alignment dowels as your guide. The clutch cover bolts should be torqued to 14ft-lbs in a criss-cross fashion. These are really the only torque specs I would truely worry about. The rest can follow the German unit of torque measurement; "Guudentite", with the exception of the driveshaft bolts and nuts. They should be close to 90ft-lbs, but I'm not 100% certain on that one. Good luck with that. Also, I would replace the throwout bearing. It's just held on with a thick wire that snaps on and off. No biggie.
The Bitch Part
Now, get some good friends that have been easy on the beer at this point. You will exhaust every curse word in your vocabulary. "Negotiate" the input shaft into the clutch disc, making sure the splines of the shaft are meshed with the splines of the clutch disc. It will be a snug fit with the new pilot bushing, so it will normally sit about 3/4 of an inch out from the motor with everything lined up. I used the bellhousing bolts to press the tranny onto the block, while making sure everything is on with the alignment dowels. Make sure all the bellhousing bolts are tight, and ease off the engine jack. Now, retighten the engine mount bolts and engine cradle bolts. Double check to make sure they are all tight.
Now, bolt on clutch slave cylinder, ground wire, starter, and connect the electrical connectors. Go ahead and install the exhaust manifold, making sure not to overtighten the headbolts. Slide in the driveshaft, remember the center support bearing's aluminum spacers, and use a crowfoot socket to torque the driveshaft bolts. Now install the y-pipe and exhaust midpipe. Now's a good time to fill the tranny with GL-5 fluid, or Redline MT90. Check to make sure everything is tight, and put on the plastic covers.
Now, reinstall the intake tube, tighten down the radiator, and reconnect the battery. Now go wash your filty damn hands, and reassemble the interior in reverse order of disassembly. Check to make sure the clutch engages and disengages properly, and go for a test drive. Be very easy on it for the first 500 city-driven miles. They all require a decent break-in period. After that, enjoy the madness. Ohh, and the downfall of lowering the engine cradle is that it messes up the alignment, because your front lower control arms are attached to the engine cradle. Make sure you get an alignment quickly after the clutch install.
Questions, comments, kicks in the ass, let me know.