my hatch's synchros are getting bad and I heard that I could flush it with atf and it would get a bit better. so has anybody done this before? and does anybody have any reccomendations for this?

Been discussed here on the board before. Lot's for, lot's against doing it.

I haven't done a Subaru trans as of yet, but I have done other manual trans with the ATF flush, using Dextron II.

Drain lube, refill with ATF. Either go for short drive 5 miles or so, or place vehicle on jackstands let run in gear, shifting gears occasionally. Drain and refill with gear lube.

Chevy/GMC even recommended using a 1/2 pint of ATF in the older 4 speed trannies, to help ease the winter cold induced stiff shifter syndrome.

Friend of mine, a big truck mechanic, recommends putting STP oil treatment in manual trans and diffs at lube changes. Swears by it. I haven't done that as of yet.

Just my .02

Try Redline...they have several different flavors to choose from. I haven't used the stuff personally but I know some people who have with great success. I've also heard lots of praise about on the Grassroots Motorsports message board. Supposed to be the best stuff on the market.

 

Redline also has this stuff called "Water Wetter", a coolent additive that supposed to do wonders for your cooling system.

I do this alot. When I first get a vehicle, the first thing I do is run Dextron III in the tranny, it does help to clean things out. Many will say that this is bad for the tranny and blah blah blah. There are quite a few auto makeers out there that actually run ATF in manuals as the recommended fluid. This isn't common on high horse applications, mostly small cars like swifts and metros. If you wanna know a secret, I run AFT in all the fluid applications on a car when I first get it, to include the engine. When I first got my ER27 it had the all too common lifter tick, ran ATF through the motor for 30 minutes, drained and refilled with 10W30, wha lah, no more lifter tick.

Do you run all ATF or just a quart or so?

yeah how much ATF / Oil in the engine for that 30 min?

so it won't make my tranny sieze up? good I'll do it as soon as I get some redline gear lube. Unless somebody has another gear lube to use.

I started running "Redline 75W90NS" a couple of months ago. Certainly the best I have tried, but not a huge improvement over "Mobil 1 75W90".

 

Both these fluids kick the backsides of all the others out there, in my humble opinion

yeah how much ATF / Oil in the engine for that 30 min?

so mobil 1's good? I can get that at teh local parts stores

the dextron flush works good and red line also makes "MTL" specificaly for manual tranys. I have used it in many vehicles even brand new cars with exelent results. it may take a little while for the tranny to start shifting better but if it is not completely worn out it will get better. my RX is a perfect example. when I picked it up it ground 3rd gear alot. now it shifts great:headbang:

 

I add a quart or dextron to the motor to flush it out right before a oil change. works cool for me.

the whole point is ATF has lots of detergent to free up gunk that has built up over time. you chose what you want to do but lots of old school mechanics have done it for years.

chose wisely

No engine oil for the motor flush. Straight ATF. I've done this many times. The first time I did straight ATF was on a motor I was getting ready to build up (so I was going to tear it down). Ran it for 30 minutes, at idle mind you, didn't stand on the gas and see how high it would rev or anything. When I tore the motor down it didn't have any gunk build up, like on the rocker shafts or lifters, the bearings looked like normal also, didn't wear them down, if you were wondering about that.

alright, well guess what i'm gonna do to my hatch tomorrow.. guess we'll find out if its a clogged oil pasage, or really a rod knock.

 

i figure if it is a rod knock the atf will make it knock harder or blow.. and if it doesn't well i'ma drive it till it blows then replace it anyways, so doesn't matter much to me..

 

i know the hydro lifters are gummed, cause they tick, rattle, and clatter like hell...

Don't drive the car with it in the tranny, the ATF won't properly lubricate the hypoid gears in the front differential (That's why the Subamatics have gear oil in the front diff), and running it in a motor you are going to tear down is fine, but if you fill a motor with ATF all that gunk it breaks free will clog your oil filter and send all that garbage through your bearings if you are not careful. Although my car was a quart low on oil, dumped a quart of ATF in there and no more lifter tap. Also dont' drive it with more than a quart or so in the motor, because ATF does not lubricate the cylinder walls as well as motor oil does.

how exactly do i do the tranny flush? one post says to drive it a little or put it on stands. one post says not to drive because of differentials. how can i get all the ATF in everwhere and all about the nooks and crannies. some help¿

well, you can fill it up with ATF and like, drive it around the block a couple of times, just go easy and don't hammer on it, then when you change it, use a 50/50 mix of synthetic and regular gear oil. Made my turbowagon shift like all smooth and stuff.

i replaced a timing chain and gears on an 80's pontiac bonneville to get it to run, only to find out it had a rod knock. crankcase was full of atf. but obviously the dude never intended to flush it out. what a waste(but i got paid to fix it!)

True that ATF isn't as good of a lubricant as regular oil. On the other hand, it does lubricate a lot better than those flushing agents that are out on the market, those are mostly kerosene. I know motor flush is one of the names. The have no lubrication properties, and they don't really clean anything at all. It is a must that you put on a new filter before and after you flush your engine, or like HS said, it will clog up your filter bad, then when your filter is clogged, the bypass will open and send that stuff straight to your bearings.

Well, I've gone and done it. I tried an ATF engine flush. I was kinda surprised how dirty the ATF was when I drained it. I've put my winter weight oil in it now (5W30), since last night was our first snow of the month, and more will be coming soon. I tried running 10W30 in the winter before, but the engine would barely crank when it was really cold, and my oil pressure gauge would almost be pegged for the first 5 minutes of driving.

 

My lifter noise went away about 5 seconds after I started it up with the ATF in it. It's not back yet, and we'll see if it ever does come back.

 

Excellent tip, Adam, you will now officially be known as "Lifter noise hero" (at least in my book)

ok now that I've found tis one agian heres my questions. how much ATF will I need, and what kind is dex II enough or should I go with dex III? where can I get some redline gear oil at?

Go to http://www.redlineoil.com . There you will find a list of dealers.

ok so how much will I need? I'm thinking about 5 quarts. and does it matter what brand or will the cheap stuff work?