Alright, so, we’ve talked about it and the theories behind how it works. Now for some show and tell.
When you first remove the transmission pan, this is the first parts you see. The grey thing in the middle is the screen. Used to call it a filter, but it really doesn’t work that way anymore. Circled in yellow is the pressure setting. In this picture, it is turned up all the way. It is normally in the middle setting. To adjust, simply push in and turn.
Just a view without the filter or wiring in place.
This ball and the plastic piece / spring that comes with it is pretty important. Make sure it goes back in.
Just a shot of the accumulators.
Here is a shot of all of the springs and accumulators and where they go. Also pictured are my home made shims.
For the hard data, here is what you need to know. I personally shimmed mine 12mm – yellow, 12mm – red, 15mm – green and 15mm – blue. These shims were acceptable for daily driving with much firmer than stock shifts but not clunking in to gear. Now that I’ve learned a lot more about these transmissions recently, I might have some ideas to make them more reliable still. Also, it is very important to install the shims inside the aluminum pistons, not in the cylinder itself – doing this would block the fluid holes in the bottom.
Update: 5/12/2018, a couple local friends have documented this on video with some clarification as well:
Update 6/2020: A fellow IS300 owner started selling these shim kits – they aren’t the limiting rods that are bad, in fact these are a good replacement for your standard coins / washer tricks.
Here’s the link he provided: https://www.ebay.com/itm/164234412405
disclaimer: I have not used them, but they appear to be the right thing!