Seks

Just looking at my spreadsheet which I keep track of on maintenance. Back in June 17 2010 (146615 km), my car had a tranny fluid change (it was just a drain and refill i believed). I have it noted down that the next tranny fluid change would be 194615 kms or on June 17 2012.

What's the concensus regarding the cheaper drain and refill versus a full flush?

CraigW

iTrader: (1)

A drain and refill is the ONLY method Honda suggest.

A flush would multiple drain and refills.

ezone

Flushing with chemicals and a machine is "strongly discouraged".

mikey1

drain and fill only

fsckewe

Multiple drain and fills will allow you to remove most of the old fluid. But keep in mind the law of diminishing returns...I think a drain and fill replaces 1/3 of the fluid.

Just as an example here are some iterations of drain and fill. Assuming capacity is 9 quarts. 3 quarts replaced every drain and fill (not sure if these numbers are accurate, YMMV) Assuming after each drain and fill the car is started and driven for a period of time thus a homogeneous mix of the transmission fluid is achieved.

1st D&F - 3 quarts new, 6 quarts old (easy as pie)
2nd D&F - 5 quarts new, 4 quarts old (removed 1 new quart and 2 old quarts, added 3 new quarts)
3rd D&F - 6.33 quarts new, 2.67 quarts old (removed 1.66 new quarts and 1.33 old quarts, added 3 new quarts)

I would stop here as it only gets worse in that you are removing more and more good fluid and less and less old fluid.

4th D&F - 7.22 quarts new, 1.78 quarts old (removed 2.11 new quarts and 0.89 old quarts, added 3 new quarts) ***You are beyond wasting money here***

gearbox

iTrader: (95)

i did 4 drain and fills when switching to different brand and it got most of the old stuff out. capacity is only 6 qts i believe so by the 4th drain and fill, you should only have less than 1/2 quart of old fluid left. you really only need to do that many drain/fills the first time. after that just do a single drain and fill each year to keep the fluid fresh.

fsckewe

Yeah, if you are drain-and-fill once a year.... one time should be enough.

Because I'm a dorky engineer, I busted out excel...and you are right. But notice, if you do just two, you have 75% new inventory.