[akauth]

I'm just finishing up my 30,000 mile service tasks (have been doing them little by little over the past 4,000 miles). Changing the thermostat and coolant today for the radiator.

You know, I've run synthetic in a trans for years, but I really am surprised that putting synthetic (well, specifically Amsoil ATF, but that shouldn't really matter) does significantly smooth out the Tundra trans.

I'm not sure if the OEM ATF is just thinner (like 5w20), or if the viscocity range of the AMSOIL is so much better (certainly from wear and stability perspectives it is superior to any regular fluid, Toyota or not) but when I flushed my trans with 16 quarts of Amsoil - actually, it might be a little more or less, I started with 5 gallons of ATF and it looks like I have about a gallons left, I had a definite improvement.

But there is noticable lack of vibration on the floor. I didn't notice it until it went away. Kind of like hearing a light buzzing sound and then suddenly realizing when it's dead quiet again.

But I do notice that when "pushing" the vehicle ahead by putting the pedal down quickly (like a fast lane change), that it moves ahead more smoothly even when it has to down shift.

Now granted, the trans is very smooth. But I definitely notice that there is less vibration (that I didn't even realize was there) and the shifts are cleaner.

I don't know if my gas mileage increased, it usually does, I haven't taken a trip yet to be sure.

I happened to grab the return coolant line and I'm also pretty amazed at how cool that fluid is heading back to the trans. If you've got a cooler and are using regular fluid, that's going to go a long way toward keeping that fluid in great shape. That return line fluid is definitely not even getting hot enough to burn you good if you spilled it on you. It's amazingly cool.

Toyota did a GREAT job on that. Mine is a 2000 so I got the cooler standard.

Anyway, fyi. I give a big thumbs up to synthetic performance in the v-8 trans. It shouldn't really be noticable as it is just ATF, but it is. Even if it didn't increase the engine life. I'd recommend a move to synthetic because there is even less vibration then there is now (which isn't even noticable until it stops, then you know it was there).

Personally, I use Amsoil (mostly everywhere on my vehicle), but I image Mobil1 or Redline would be fine too. Redline might even be better.

alan