Transmission Flush !

[Gnyce09]

Had an f22a6 engine swap about 3years ago and negligence on my part didn't stay on top of any fluids. So its about that time i do a few flushes. I'm starting out with a transmission flush. Just looking for some knowledge on how-to's and what type of transmission fluid should I get, what I should look for and what would i be expecting

Thanks


CB74LYFE

[deevergote]

I assume this is an automatic transmission? (I'll never understand why people always ask transmission-related questions and don't specify what they have!)

A flush is not recommended. Doing so in an older transmission usually loosens deposits that have basically become part of the transmission. Yes, it'll be clean, but any wear may become far more evident.

Just do a fluid change, not a flush. Use Honda fluid ONLY. Nothing else. No additives. Just the proper amount of Honda fluid.

[Gnyce09]

Im guessing i should've said automatic but what would be the difference ?

and with the fluid change your just draining once and refilling correct ?

[deevergote]

Yes, just drain and fill.


It matters becaue 1) automatic and manual transmission fluids are VERY different, and 2) a "flush" generally isn't performed on a manual transmission anyway... which would have made my argument against it moot.

So if you asked for the best fluid, and someone told you "GM Synchromesh!"... you'd do a good deal of damage to your transmission if you followed that advice blindly! GM Synchromesh is a manual transmission fluid (and what I use in my car... I feel it is superior to the Honda manual fluid... though I wouldn't put anything other than Honda fluid in a Honda automatic.)

[Gnyce09]

thanks for the advice

[19dabeast85]

You have old used fluid that has lost its detergents, lubricity, resistance to pressure, heat exchange ability and has worn metals floating around in it. You need as much of that old fluid out as possible, leaving it in can do nothing but harm, anybody who tells you to leave OLD automatic transmission fluid in the tranny to keep it from "leaking" or "removing deposits" doesn't know what they're talking about.

This is what you need to do exactly:

1. Find some of those really small, round earth magnets and slap a few of them on your tranny drain bolt.

2. Drive 20+ miles then drain & refill 3 quarts wiping inside of drain bolt clean. Leave magnets on drain bolt.

3. Drive 300 miles then drain & refill 3 quarts wiping inside of drain bolt clean. Leave magnets on drain bolt.

4 Repeat step 3.


You have flushed 9 new quarts of ATF through the tranny diluting the old stuff and slowly cleaning the light gunk out. You have gotten 95%(IMO) of suspended metallic particles out of the fluid. You now have good condition fluid in the tranny that can stand up to the pressures, lubricity, and cleaning requirements of the auto.

Leave the magnets attached to the drain bolt and from this time forward, drain and refill 3 quarts of ATF every 3rd oil change (9-12k miles).

[deevergote]

That does indeed make sense. That is changing the fluid (and yes, I forgot to mention that it is important to circulate the new fluid through the system to clean out the torque converter... at the time I gave my advice, I didn't know if I was wasting my time with auto advice on a guy with a manual...)

The "flush" I am referring to involves hooking the transmission up to a machine, whcih forcefully pumps the fluid out. This has been known to cause old, worn transmissions with old, rancid fluid in them to fail very quickly. If you take your car to a shop for a "flush", that is often what you would expect to get.

I don't know what I'm talking about though. Don't mind me.

[19dabeast85]

Wasn't directed at you Deev, I was going ahead and stating it before everyone else who is afraid of new fluid in their autos posted in here messing up good information in the beginners section. There's alot here who will post "don't ever change your auto fluid!". I should have clarified that at first.

Yeah the full machine flushing will tear up a Honda transmission almost 100% of the time.....it guarantees the shop future transmission work.

[deevergote]

Ah, ok. Premtiive dismissal of lousy information. Gotcha.


Yeah, the way you described is the best way to change the fluid. Force-flushing it is VERY bad, especially after years of neglect. Most people know to change their engine oil, but very few bother with their transmission fluid (hell, even I do it, and I know better! My Fit's fluid is original after 183k... manual, but that's still not good!)

Many of these 200k mile CBs that people have are still running the ORIGINAL transmission fluid from 20 years ago. That's as good as a transmission case filled with Aunt Jemima.