I have an auto (Nissan) and have been using Mobil synth ATF and Lubegard trans additive.
Have driven this car for about 70K miles (has 158K on it) and early on it had a problem where it wouldn't shift right...failing to drop into 1st...but doing so with a clunk after stopping.
I fully flushed the ATF several Xs and added the Mobil ATF. This didn't solve the problem...but when I added the Lubegard additive...the "clunk" happened one more time and hasn't happened since.
Basic idea is that to prolong the life of an auto...the flushing process and then use of synth ATF will remove some varnish and clutch grit...and the Lubegard will further reduce the trans temps and help reduce friction.
Need to be careful and use the right type for your trans though.
There is a difference between a machine type flush and doing it yourself thru the radiator cooling lines. The DIY method involves nothing more than exchanging in clean ATF...running it awhile and then flushing it again.
Eventually you put in the synth ATF.
Using a machine or a flushing fluid CAN cause problems.
Why do I use Mobil synth ATF and Lubegard? The Mobil is easy to find...but isn't cheap. The Lubegard ($12?) is endorsed by several OEMs...and can be found locally also (NAPA?)...but main thing is....it works.
Leading the perpetually ignorant and uninformed into the light of scientific knowledge. Did I really say that?
a new policy....I intend to ignore the nescient...a waste of time and energy.
If that clunk is still occurring to a degree you might want to reset you ECU. The easiest way to go about it is remove the negative battery terminal for 5 mins. stop on the brake pedal a couple of times to purge any electrical charge, and hook the terminal back up. Basically all it does is returns your car to factory setting for shift point and such. Compaq888 had a similar problem and this supposedly fixed it.
To me this sounds similar to putting gm syncromesh in a manual transmissions; it stops grinds. But what it really does is leave the gear(s) grinding away and the syncros dying, but you don't have to listen to it.
I put M1 ATF in our Accord 5AT. Did a complete flush and havent looked back. The Accord shifted so smooth it was doing its best to be a GM slush box. The M1 firmed the shifts up a tad. Also droped my tranny fluid temps a hair messured with my fluke and temp prob zip tied to the dip stick. When a AT shifts buttery smooth its waisting hp, energy and makeing more heat. All of which are very bad IMO.
Every thrid oil change I drain 3 qts of tranny fluid and replace the tranny filter and fluid.
If Honda does the up coming Accord Hybrid right we mite trade our Accord EX. But Im not holding my breath. I can see rear drum brakes and a CVT. The rear drum brakes would kill the deal. If they only offer a CVT ,, o well. It will be the wifes car and shes lazy and dosent like to shift gears.
So in the meantime. I will keep the fluids and filters maintained and the shifts positive. ( not harsh )
The grinding and syncro problems are almost soley in the 6MT's in Hondas line up. I havent heard of any 5MT problems in late model Accords or Civics. Just TL, TSX, Accord and Si.
IMO alot of the problems folks are having are brought on by the owners. I see so many folks that back a car up and before its stoped there craming it in 1st gear to the tune of complaint from the gear box. My Civic and Ranger both compain about doing that. Then there are the folks that blow afew shifts going into 2nd or 3rd at high rpm's and loads. Then a few weeks later. Darn,, 2nd or 3rd gears are now goofy. The 6MT's seem to not be quite as strong as a 5MT.
As trannys get more complex and fragil they need far more mait. IMO. Its ubber cheap ins.
I also did a flush on the Civic's 5MT when I did the 1st oil change. I put Honda MT fluid back in it after I flushed it with a cheap 5-w30. Next oil change its going to a M1 oil. Just havent decieded yet which one.
09 HCHII, w/Navi
07 Mazda3 S Touring, 5MT
Mild Hypermiler or Mad Man?
...What's wrong with rear drums? I wouldn't trade my rear drums for anything in the world!
I tried to change rear drum shoes once - ugh! Volvo 240s have the easiest changing front and rear disk brake pads anywhere, I think. The caliper stays mounted, you just get the retaining clips off and pull the pads out with pliers or screwdriver blade. Press back the pistons, smear on silicone slide stuff, slide new pads in, put the retainer things in, ta-dah - you're done!
Unfortunately with auto trans the 3000 lb. beast is only good for about 24-25 mpg in clean winter weather. In summer I've seen 29 in the past; I hope to see 30-35 highway this coming summer by coasting in neutral (engine on) etc. Most folks are lucky to see 24-25 mpg highway in these.
Currently getting +/- 50 mpg in fall weather. EPA is 31/39 so not too shabby. WAI, fuel cutoff switch, full belly pan, smooth wheel covers.