The age old question, To Flush Transmission or Not

[wm69]

When i flushed my trans i just removed the line from the supply line from the trans to the radiator and turned on the engine and let it pump till it sputtered then shut it off and filled it up then repeated till the oil coming out was like new....i think about 16 quarts or so

The oil was dirty red but it didn't smell burnt.

Was nosing around under the 4runner yesterday and thought about doing this. I see two rubber lines going into the bottom of the radiator. I assume both of those are tranny lines. Which one did you pull off, and I guess you just run the hose into the bucket? Does anything come out of the rad fitting or would you have suction there? I guess if fluid is pouring out of the rubber line you would still have a bit of old fluid in the radiator line and the other line from radiator to transmission, right?

I think I'm going to switch to Mobil 1 after seeing more and more people who swear by the stuff. If I'm going to switch I think I'd want to get all of the old Dexron out of there. They're supposed to be compatible, but I'd rather get all syn in there.

 

[004Gunner]

I had mine flushed at 60k with synthetic and was told it would be good for another 90k. I'm going to flush it again when my runner hits 120k not 150k like the shop told me. I didn't notice any real improvement after but I baby my trans. I like the idea of changing out 95% of the fluid with a flush as opposed to what 50%? with a drain and fill.