Lexus IS 300 DIY 5 Speed Manual Transmission Fluid Change

Part of the 60k service is to change the transmission fluid. Here's a write up with pics on how to do it yourself.

• 3 quarts manual transmission fluid - I used Redline MT-90 because that's what I've always used in my track car (a turbo 1G DSM) and had good results with it. Read this 5 speed tranny thread at my.is if you need help deciding on what brand to use. Some other popular brands are Royal Purple, Amsoil etc
• Jack and jack stands - Remember, NEVER use the jack alone (especially the scissor jack that comes with the car) to support the car. ALWAYS support it with jack stands if you're going to be working under it.
• 24 mm (or 15/16 inch) box end wrench and socket - You might not need both box end and socket, but for me, it was easier to remove the fill plug with the box end wrench and easier to remove the drain plug with the socket. Both the fill and drain plugs are supposed to be 24mm, but I didn't have a 24mm box end wrench sitting around so I just used a 15/16 inch and it worked just fine. As a matter of fact, it seemed like the 15/16 inch fit better than the 24mm.
• Breaker bar - Optional if you're removing the drain plug with a socket. Otherwise just double up the box end wrench and you should have enough leverage to remove the plugs.
• Washers for the plugs - You can get these for a few cents at the dealer. My old ones were actually fine but I used the new ones since I already bought them.
• Pump or tubing - You'll need this to fill the tranny with new fluid. I used a pump (see pic below). You can get it at any auto parts store.

Here's a pic of the pump (the tubing was clear, it turned orange red after I used it with Redline Shock Proof on the other car):

Pic of the Redline MT-90 (the 2 bottles of 75w90 gear oil is for the rear diff):

Pic of the 24 mm socket and 15/16 in box end wrench:

1. Jack the car up and support it with jack stands
2. Remove the fill plug

   This is where you'll need the 24 mm (or 15/16 inch) box end wrench because the socket won't fit (see pic below).

   This has probably been said a million times, but make sure you can remove the fill plug before you drain it.

   I made the mistake of draining first when I did my other car and well, sure enough Murphy's Law kicked in and I ended up spending the next 3 hours filing down a rounded off fill plug (what started out as a 17mm plug wound up as a 13mm plug by the time I got it off)

   
3. Remove the drain plug and drain the transmission fluid

   I used the 24mm socket and extension here because it was kinda awkward getting the box end wrench in there (you'll see what I mean once you're down under the car). I suppose you can do it with the box end wrench if you remove the plastic shield.

   By the way, you might wanna move back a bit before you remove the plug completely because the fluid will gush out and a good amount will most likely end up on your face (don't ask me how I know this)

4. Let the old fluid drain completely and replace the drain plug

   Go take a break (or wash your face if you messed up doing step 3) and let it drain for a while, then replace the drain plug. Dont forget the washer.

5. Fill with fresh tranny fluid

   Shove enough of the tube into the filler hole so that it sits firmly and won't fall out when you pump new fluid into the tranny.
   Here's a pic:

   

   I had to cut the top off of one of the bottles because the pump wouldn't fit in it:

   

   I kept pumping fresh fluid into it until it started dripping out. Ended up using nearly all of the 3 quarts of the transmission fluid.

6. Replace the fill plug

   Since I didn't want to lose any of that precious MT-90, I temporarily plugged the hole with my thumb with one hand while I was grabbing the fill plug with the other. Tighten the plug and you're all done!