synth ATF

[NomadTW]

when you guys switch to synthetic ATF... do you drain the trans completely of all 10qts of the old fluid or do you just drain what you can from the pan, and whatever is left you let mix?

if you drain it all how do you go about doing that?

[lee]

I don't think it can be 'all' changed out with the transmission in car. I assume that because I'm under the impression that the fluid flow internally sends some out to the cooler and returns some to the pan. [you've probably heard the cruder definition of what assume means though, so...]

that said, a drain and fill of about 7 qts, gets you 70% of the way there. run it to mix, then do it again and you get about 91% (70% of the 30% old left over), etc. until you give up satisfied or your pocket book is empty

given a 10 qt capacity and a torque converter that holds 3, I'm under the impression that a flushing machine style change uses up around 15 qts - and you are then so near 100% as to be indistinguishable.

[SVXRide]

I just added the Mobil 1 synth after dropping the pan. Word of caution here - the front seal on my trans was leaking "at speed" (i.e. no leak when parked) and after I went to the synth I got a wonderful (NOT) puddle under the trans when parked. I'm now switching back to the organic stuff....
-Bill

[lee]

Originally posted by SVXRide
I just added the Mobil 1 synth after dropping the pan. Word of caution here - the front seal on my trans was leaking "at speed" (i.e. no leak when parked) and after I went to the synth I got a wonderful (NOT) puddle under the trans when parked. I'm now switching back to the organic stuff....
-Bill

excellent point. if the tranny has many miles on it, there is a good chance the change to a synthetic ATF will cause it to start leaking. the reason is synthetics "clean" up the gunk that builds up at the seals. for those wanting to go the synthetic route on an older tranny, I would look into a conditioner to be used before switching fluids.

here's one source: www.auto-rx.net

[LarryIII]

For the first year that I owned my '92, I changed the synth. ATF every time I changed oil (every 3000 mi.). That way, I think that all of the original ATF was eventually removed from the tranny system.

[ensteele]

Originally posted by LarryIII
For the first year that I owned my '92, I changed the synth. ATF every time I changed oil (every 3000 mi.). That way, I think that all of the original ATF was eventually removed from the tranny system.

How many times was that? Two or three times?

The ONLY way to properly remove the stuff in there and get another fluid into the system is with a circulatory flush.

BG has a good one, your dealer may be able to do it for you.



Why do you want to use synthetic, by the way? Standard DexIII works great, in fact it's one of the most durable, well engineered fluids on the market. What's the point in changing?

Originally posted by Porter
The ONLY way to properly remove the stuff in there and get another fluid into the system is with a circulatory flush.

BG has a good one, your dealer may be able to do it for you.



Why do you want to use synthetic, by the way? Standard DexIII works great, in fact it's one of the most durable, well engineered fluids on the market. What's the point in changing?

Good point, Porter.
Our Senior Master Tech advises against going full synthetic in a Suby tranny because it's too slippery. You want some friction in there for it to work correctly. If you really want synthetic, he suggests either a blend of synthetic and regular (which is what I do) or full synthetic with a friction modifier. His recommendation is to use regular, good quality DEXIII, and change it every 15,000 miles.


Dave

Subaru recommends against the use of Synthetic ATF in their automatics. When I worked at Kerven, they would only use Synthetic if the customer specifically requested it, and the car was out of warranty. I would recommend using Genuine Subaru ATF, or another brand name Dextron III. (Castrol etc)

Mike

[STORMINORMAN]

Synthetic ATF has a couple benefits, including more resistance to overheating... I guess if I was going to leave it in for 30K I would go to a Synthetic ATF: Redline, M1 or Amsoil.

NOTHING in a can or bottle will fully repair a mechanical defect.

I'm in the middle of an Auto-Rx transmission application on my SVX: I 1st changed out the ATF fluid (with Castrol), back-flushed the cooler, then changed the filter and hoses. I plan to run it 1,000 to 1,200 miles as per their instructions, replace basically all the fluid by dropping the pan, replacing the internal tranny screen/filter, refill & run a dozen quarts through using the return hose from the cooler when I change the ATF filter, again...

Using Chevron Dextron III as it was 79 cents per quart. I don't find the fluid replacement any more complicated than an oil change. I mean DUH! there is a drain plug and a hose from the cooler with a hose clamp to unhook: not exactly brain surgery...

I kept the ATF filter from the initial change and will be cutting them both open to compare. My transmission (a factory rebuilt replaced under warranty in 1998 @ 57,xxx miles) has never given me a problem (I'm sure it had all the relevant upgrades) and the fluid (which I normally changed every 15-20K) has always been clean, pink and unburnt. Routine maintenance is certainly the key to reliability & good performance, IMHO.

I'll probably put my new radiator in at 120K when I replace (or HAVE replaced) the timing belt, water pump, maybe the cam & crank seals... My last repair on the crack at the radiator valley seems to have finally been 100% successful. I got a deal on the new factory radiator and since I plan on driving & enjoying the SVX for the forseeable future it seemed a reasonable investment.

Admittedly I don't feel we are very "hard" on our SVX, which we purchased new 116K ago. I go much faster on my ZX-11...
Last year's 6K+ cross-country trip was a PURE DELIGHT. I was never more impressed with the SVX than when I drove non-stop (except for gas in, gas out) from Denver to PDX in 22 hours. That was including (rear) wheel bearing getting noisey in Wyoming @ 85 mph in a downpour ( about 8 inches of water on the highway! WHEEEEE!!!!!!!!!)! Rum-rum-rum-rum-rum... RUM-RUM-RUM!

I've used Auto-Rx previously in the oil in the SVX, my Ford F250 (both the 460-carb & in the C6 as we speak), the '73 450SE(oil & tranny), the oil in the 420SEL (had just had a MB transmision service when I found out about Auto-Rx) and it is in the wet-clutch ZX-11now, too.

In my opinion & in my experience it works as advertized and I don't hesitate to recommend it to anyone. IT WILL NOT FIX A MECHANICAL DEFECT OR PROBLEM. It WILL gently clean your engine or transmission. Seems to work on leaks from rotating seals (like cam seals), too... It did for me.

Cheers!

[htyei]

I had redline hitemp atf for 4 years (drain and fill) and it still looked new when I changed this year.... Of course who can say they've driven only 25k miles in 4 years other than me

(Btw this is with two external atf coolers in serial + original one throught he radiator and two changes of the external ATF filter kit in between.

[Mr. Pockets]

Originally posted by htyei
I had redline hitemp atf for 4 years (drain and fill) and it still looked new when I changed this year.... Of course who can say they've driven only 25k miles in 4 years other than me

I drive my SVX about 3,000 miles a year.