Akom's Tech Ruminations

Various tech outbursts - code and solutions to practical problems
Low Tech Hacks

Changing Manual Transmission Fluid in a Scion tC

Posted by Admin • Saturday, April 11. 2009 • Category: Low Tech Hacks

The goal is to replace the stock (assumed: mineral oil) transmission fluid with Amsoil synthetic. Amsoil is my personal preference, while synthetic is my maintenance goal. I set out to do this as our vehicle was approaching 60K miles... OK so I meant to do this about 60K miles ago, but better late than never. The car is now 3 years old (exactly).

There isn't anything too difficult about this job, but when I got under the car I discovered a filler bolt labelled "Consult Owners Manual Before Refilling"... now I've done a fair share of work, but this looked suspicious. So I set out to investigate.

I climbed out from under the car, and pulled out the owers manual. There isn't a single thing in there about transmission fluid! I couldn't even find anything about automatic fluid, had my car been automatic. I checked the maintenance schedule... same thing - not a peep about changing trans fluid.

So I checked the forums, and that's when I discovered that while there appears to be nothing to this warning, everyone who has done this job has made a huge oily mess under (and of) the car.

As it happens, I was able to do this job with zero mess - this is how:


  • 3 quarts of 75w-90 GL-5 Gear/Transaxle heavy oil. I like to do each job once, so I'm putting in synthetic (Amsoil stuff claims 500,000 mile lifespan - basically forever)
  • 24mm socket (low profile) and/or 24mm box wrench. A 15/16" will work, as large wrenches seem to be uncommon
  • Drain Pan
  • A pump. What pump, you ask? - How were you planning on convincing your gear oil to get into a hole above your head, exactly? OK you may be able to improvise a funnel/hose contraption and pour from above the engine, but you'll find it difficult to know when to stop pouring :-)... I use the Amsoil pump, it screws right into the bottle. A drill pump would probably work, but be careful if you've used it for anything else in the past.
  • Some rags/shop towels won't hurt
  • Disposable gloves. Highly recommended


  1. Drive the car Warm fluid flows better and more will be drained.
  2. Lift the car. In a perfect world you'd have a lift, but this may be even better: Drive the front up on ramps, and jack up the rear at the axle (if you had one) center point. Now you can tilt the car forward/back with the rear jack, and you are safely under the front which should not fall on you
  3. Start out with the rear of the car down.
  4. Get your drain pan and tools ready
  5. Open the filler bolt first. This will smooth out the drain flow (won't gugle). You may hear a little air pressure, so open slowly. A few drops may come out. Check the level with your finger to see if the fluid level was incorrect (just so you know).
  6. Now start unscrewing the drain bolt. Back it off with you fingers until fluid starts to trickle out, then very, very slowly back it out until nothing but your finger pressure is holding it in place. Now hold it it firmly (if you haven't been, you now have gear oil everywhere and the drain bolt is half-way across the garage!) and carefully tilt it up, so the fluid can drain out from under it (see photo). This directs the flow downwards instead of onto the subframe and everything else
  7. Hold it for 1-2 minutes, and then it will be all over. You can put the bolt down now. Allow the old fluid to trickle out for some time (go get lunch). Lower the back of the car if it isn't already down to help it flow
  8. Raise the back of the car to make it as horizontal as possible.
  9. Put the drain bolt back in, tighten to 36lbs (I believe, check your manual)
  10. Set up the pump and start pumping into the filler opening
  11. The tC takes 5.7 pints which is 91.2oz. That's almost 3 quart bottles.
  12. As you are nearing the end, start paying attention. If your filler hose is laying on the bottom of the opening, it may prevent the fluid from escaping when full, and you will overfill, so move it around a bit. When fluid starts spilling you are done.
  13. Remove hose, allow any excess to drain, then put the plug back in and tighten (again I think it's 36lbs)

Hopefully your car is shifting better now, your fuel economy may be somewhat improved (hey, it could happen), and hopefully your transmission will outlast you.


tC on Ramps
Drain Bolts locations (opened)
Directing fluid flow
Pump In Bottle
Pump In Use

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  1. Hi, I just wander how you drove your tC on this ramp. I tried but it was just not able to get on this kind of ramps. I have to get a pair of more expensive ramps for lower profile car.

  2. It technically doesn't fit over the ramps, but you can jam them in under the bumper - the car actually lifts up a little bit on the springs, maybe 1/2 inch. Makes a really fun squeaking sound too on the way up and down.

  3. I guess it must hurt and make some scratches under the bumper when you try to push in the ramps, right? ...

  4. They are painted metal with a smooth surface, so they don't leave a mark - not that I really look under the bumper. Besides, it can't be worse than asphalt strikes which are frequent on my driveway.

  5. Thanks for your reply. I want to get a slipper to help me slide in and out under the car. Can you tell me the name of it? It's the yellow stuff with wheels in your first picture.

  6. It's called a Mechanic's Creeper. Search google for that phrase or stop by any auto parts store or a large department store.

  7. How were you able to get the drain bolt off. There is very little room in there for a wrench. I'm having no luck finding a wrench that can fit in there

  8. If I recall correctly - a box wrench or a regular adjustable wrench (to loosen), then by hand.

  9. Maybe easyer pouring it down the dip stick then a pump. I'm doing this fluid change soon as my shifter won't come out of first sometimes.

  10. That would work great if the manual transmission had a dipstick...

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