Originally Posted by lolasolomonjack
1) my shop has given me a quote of $245 for a transmission fluid change. I have not actually asked them if they are planning on doing a change or flush. Is this price high, or normal?
2) I was told that the fluid is dark, but not stinky. Should a change or a flush be done?
3) I use full synthetic for my oil. Should I use full synthetic for my transmission?...
The price is a little high. Most dealers charge around $200 for changing the full capacity of 10+ quarts. This is called a flush because it is a complete replacement, but is not a flush. Dealers do it using the transmission's own pressure to circulate old fluid out and new fluid in, using a pump-less double-chambered tank made by BG. The transmission pushes old fluid into one chamber which pushes new fluid out of the other chamber and into the transmission. It's not the dreaded power flush that people imagine, as the transmission is just pumping the fluid around with its own internal pressure as usual:
"BG PF5 Power Flush and Fluid Exchange System... has no power supply of any kind..."
BG Products, Inc.
If the fluid is dark, it should be flushed as above. The alternative is to drain and refill the transmission 2-3 times separated by short drives. Because each draining only removes 3.75 quarts, and new fluid then mixes with the old, the total fluid supply only gradually becomes newer through serial dilution. But it takes your time, and wastes several quarts of new fluid.
Your year requires High Performance ATF such as:
Subaru ATF/HP (P/N SOA868V9241).
IDEMITSU ATF HP.
Castrol Transmax J.
Don’t use Dexron 3.
The proper synthetic recommended by AMSOIL should be OK, but the dealer likely won't have it or do it. And if you do the serial drain and refill, the waste will be unusually expensive, and the result will be a mixture of some old dark conventional fluid with new synthetic.
Some people do a single drain and refill of the 3.75 quarts every 10-15,000 miles, and so maintain a relatively fresh mixture of fluid. But since you have a 2007 with some years and miles, and a turbo with its power, and have already darkened the fluid, I think you should get the flush.