It was empty

I went camping this weekend, and on the way back I climbed up a deserted, winding mountain road. It was fun to throw a 1-ton van around like it was a sportscar!

But as I got to the top of the hill, my transmission (under my feet) felt really really hot again! Oh no! Didn't I just change the fluid and solve that problem?

I found a flat spot near the top of the road, and checked. The transmission dipstick was bone dry! DOH! I put in a quart of fluid and kept on going. It helped a little.

When I got back into town, I checked on a flat spot again. Sure enough, still empty.

The service manual says that it takes 20 quarts! It says I was supposed to put in 14 quarts, then put in a half-pint at a time, with the engine hot and running, run it through all the gears, then check again, until it got to the fill line, which should be 20 quarts. Well, the dipstick is the fill hole, so this is a huge pain, because not only does this take forever, but it takes even longer since the dipstick tube gets coated with fluid and the reading is useless. You have to wait like an additional half hour for the fluid to drain out before the dipstick reading makes any sense.

So, I just cheated, and since there was 13.5 quarts of old fluid that came OUT of the transmission, I just put 13.5 back IN and figured that should be the same. I assumed that there just was more fluid somewhere in the system that I didn't manage to drain out when I cleaned it.

Well, I was wrong. The transmission was dangerously low all along, and I filled it dangerously low with new, clean fluid. That was not smart.

So what I've done is, the slow way: fill it with a half-pint, go drive somewhere wasting fuel to heat the thing up, find a level spot, check it, fill it with another half-pint, go do some more useless driving, then check it again, fill it again, etc.

Slow and wasteful of expensive fuel. But, it works. I've got the transmission full to about halfway up the hot fill range. I'd like to top it up a bit more, but that can wait. It does seem to run a lot better now, and the grinding sound I had for years is gone. Temperature feels fine too.