An easy cure for RSN?

My van starts to do RSN about 20,000km after an ATF change using 236.14. When I was due to change my ATF again after 60,000km, I decided to only drain the pan - so about 3 litres. I decided to do this because the fluid that came out of the pan was in pretty good condition. The interesting thing is that the RSN has totally stopped with just that 3 litres of fresh 236.14.

So assuming the RSN holds off for a decent while, would it be a good idea to just drain 3l from the pan say every engine oil change (around every 10-15k km for me)? Then do a full trans service maybe every 100k? Its so easy to do a pan drain especially when you are under there anyway doing the engine oil.

owner said:

My van starts to do RSN about 20,000km after an ATF change using 236.14. When I was due to change my ATF again after 60,000km, I decided to only drain the pan - so about 3 litres. I decided to do this because the fluid that came out of the pan was in pretty good condition. The interesting thing is that the RSN has totally stopped with just that 3 litres of fresh 236.14.

So assuming the RSN holds off for a decent while, would it be a good idea to just drain 3l from the pan say every engine oil change (around every 10-15k km for me)? Then do a full trans service maybe every 100k? Its so easy to do a pan drain especially when you are under there anyway doing the engine oil.

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You did it at 60,000 km (36,000 miles) and it made a difference. Every other oil change is about 20,000 miles?

My mode now is pan and TC drain every 50 - 60,000 miles with filter every 3rd drain. No RSN, but the 2004 has the Doktor A fix from the trials. My 2006 doesn't seem to have any LHM problem (approx. 150,000 miles to date).

I believe some dealerships only do a pan drain for filter changes, no TC drain.

Keep us posted if you do it.

vic

Yep I'm doing it now. Currently 3k in on the 3l of fresh (with 5l of 60k/5yo) fluid, and still not a hint of RSN. Next engine oil change will probably be in 10k, so will see what the RSN situation is like then.

If RSN is still negligible then, I reckon the 3l pan drain method every engine oil change is g2g. This would be beyond the worst case scenario for my method - ie. having 3l of 13k fluid, with 5l of 73k fluid. If my process was followed for a while, the percentage of high km fluid would decrease over time.

I actually don't care much about RSN, the main reason I'm doing this is:
1. Its way easier just draining and refilling the pan each time if you're under there anyway.
2. Ability to catch certain trans problems way earlier (could even do proper UOA).
3. Reduced crap buildup in the trans.
4. Related to #3, not shocking the trans with 100% new fluid which could suddenly dislodge lots of said crap.
5. Reduced/no RSN is just the icing on the cake.

I can't think of any downside at this stage, happy to hear any theories.

Well I'm 8000km into this experiment, and the RSN is only just starting to appear now. So I reckon this pan change method is really good.

This current ratio of new/old is the worst I will ever have (being the first time I did the 3l change). Next time the ratio of new/old will be way better, and it should stop RSN for longer than 8000km.

I'm not sure my engine will last that long though. The donor vehicle I am looking at for my engine swap also has a freshly rebuilt 722.6 attached, and it would be rude not to put the trans in my van since I'm doing the engine swap anyway.

owner said:

... The donor vehicle I am looking at for my engine swap also has a freshly rebuilt 722.6 attached, and it would be rude not to put the trans in my van since I'm doing the engine swap anyway.

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Rude and more work. I'd just swap over the engine tranny combination for no other reason than the time saved, but I'm lazy.

Thanks for the feedback.

vic

Update: Today I was due for another engine oil change and so I did the trans pan drain again as per my new RSN reduction schedule. So this was a full 15,000km since I last did it.

My van had developed some light RSN from about 8k and this has gotten to what I would call mild RSN over the remaining 7k. Remember, this is on 60k fluid which had 3l swapped out 15k ago. The fluid that came out was very good. Light brown but still had some redness and nice sweet smell, and not the slightest hint of debris in it.

So now my ATF should be in better condition than last time. I know its not how it works, but for illustration purposesI can work out the average km on my ATF cocktail...

I started with 60000km on my ATF.

When I first did the 3l drain I had:
5l of 60k fluid and 3l of 0k fluid. Average of 37500km ATF cocktail.

So just before I did the change today I had:
5l of 75k fluid and 3l of 15k fluid. Average of 52500km ATF cocktail.

After the change today I have:
5l of 52500km ATF cocktail, and 3l of 0km. Average of 32813km on the ATF cocktail.

Just before my next OCI I will have :
5l of 47813km fluid and 3l of 15k fluid. Average of 35508km ATF cocktail.

And just after my next OCI I will have :
5l of 35508km fluid and 3l of 0k fluid. Average of 27817km ATF cocktail.

As you can see my ATF cocktail is getting better and better with each iteration (It is actually better than this because you get about 3.2l not 3.0l). And its so easy just to whip out the plug when you are already under there doing the engine oil.

In my experience, old transmission oil and dirty transmission oil and dirty transmission conductor plate all contribute heavily to RSN. 95% of the time all a transmission needs is a full transmission service to get things running smoothly and quietly again. your experiment would seem to confirm this because you are replacing old dirty fluid with new clean fluid a little bit at a time. However, your RSN continues to return probably because you are not cleaning those microscopic metal filings off the plate and shift solenoids.

We shall see. This 2nd change will be the real test. If I can get a lot closer to 15k this time before RSN then I will be happy.

Going by the average cocktail numbers it should be a lot better this time. Even though the average km is not a good measure, its really the replenished additive package that im doing thats making the difference. Its like giving my trans a regular shot of steroids.

owner said:

... Its like giving my trans a regular shot of steroids.

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Maybe more like getting some non-anemic blood and a hand full of vitamins.

Keep up the good work.

vic

Reporting in after the next change today @15,000km. I started getting a touch of RSN at about 12k this time.

The fluid that came out looked very very good and no hint of particles. Still quite red too.

I really do think this is the way to go now. It gives you a lot of peace of mind seeing the pan fluid so often, let alone the huge reduction in RSN. And its so easy to do alongside the engine oil change. Buying the Fuchs 4134 in bulk brings down the cost to well under $10/l.

owner said:

... Buying the Fuchs 4134 in bulk brings down the cost to well under $10/l.

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With your relatively frequent changes I would suggest using a synthetic ATFIII vs approved fluid. It should save even more money.

At one time synthetic ATFIII was listed for NAS aka NAFTA T1N's in the operator manual.




vic

Aqua Puttana said:

At one time synthetic ATFIII was listed for NAS aka NAFTA T1N's in the operator manual.

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Yep same for the Oz owners manual.

Either way the Fuchs 4134 is cheaper/same price as other synthetic ATFs here in Oz.

As an aside, I got a little RSN about 5K kms after changing the oil/filter etc. I had maybe a little more before oil change. Right after the oil change probably zero to a tiny bit. A don’t know how bad my RSN is because I throttle out of it. I have always just throttled around it. This is my first automatic transmission, so when I get RSN it reminds me of lugging an engine. Since I can’t clutch and change I usually just back off a little and that seems to clear it.
To be clear, I am afraid of the fragility of automatics, so I baby this box.
I have always babied my manual transmissions as well, never grinding, slamming etc...
I always drive 10+ year old vehicles so maybe I’m just extra gentle.

Patrick of M said:

...
To be clear, I am afraid of the fragility of automatics, so I baby this box.
I have always babied my manual transmissions as well, never grinding, slamming etc...
I always drive 10+ year old vehicles so maybe I’m just extra gentle.

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Be careful with extra gentle. I drive like the old man I have become so not a bunch of horsing around from me either. I occasionally get a flare shift in the 2004. I've learned that some spirited driving up freeway on ramps makes the symptom go away.

My opinion.
Putting your foot into it once in a while on a up to temperature drive train is a good thing, not a bad thing. To be clear, I'm not suggesting squealing tires from a dead stop, just occasional hard(er) acceleration up an on ramp to cause somewhat spirited shifting.

vic

Aqua Puttana said:

Be careful with extra gentle. I drive like the old man I have become so not a bunch of horsing around from me either. I occasionally get a flare shift in the 2004. I've learned that some spirited driving up freeway on ramps makes the symptom go away.

My opinion.
Putting your foot into it once in a while on a up to temperature drive train is a good thing, not a bad thing. To be clear, I'm not suggesting squealing tires from a dead stop, just occasional hard(er) acceleration up an on ramp to cause somewhat spirited shifting.

vic

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Well I drive like an old man as well....that means I sometimes get pissed off. So yes I occasionally stomp on it. Just not for extended periods, btw the way, I feel the same about suspension, it needs to be worked sometimes. All my rides get driven over curbs etc so that full suspension travel happens, good for the shocks to travel a bit....missing speed bump signs helps.