Change Automatic Tranny Fluid Ya or Nah

BryonTheCanadian · Post by **BryonTheCanadian** » 11 Jan 2019, 10:27

I have a new to me 2006 XC70 in great shape with 250,000 km or 150,000 miles. The transmission is not perfectly smooth on shifting. I've heard it both ways the changing the fluid blows the transmission and others say its works great. The volvo tech said even volvo suggests you leave it... Whats the concencius here? Any experienced opinions thx

Post by **Rattnalle** » 11 Jan 2019, 10:56

If it goes bad when you replace the fluid it was already bad but just hadn't shown it quite yet.

If you really want to play it safe then add an inline filter to the return line then replace what drains from the pan a couple of times with some driving in between.

Post by **850 LPT** » 11 Jan 2019, 10:57

I'd say you can save this tranny by starting to do a few "drain and fills". That "never touch it" philosophy is bogus.

Dirk

pgoes · Post by **pgoes** » 11 Jan 2019, 11:41

Do an incremental 'flush and full' as described in this video:

My car was showing typical symptoms of 'shift flare' where the 2nd ->3rd shift seemed like it would briefly go into neutral. I don't think the transmission had ever been serviced (111,000 miles). I did a flush & fill with about 10 liters (Mobil ATF3309) and the problem disappeared completely. The process was really easy!

BryonTheCanadian · Post by **BryonTheCanadian** » 11 Jan 2019, 12:47

This is gold

Post by **850 LPT** » 11 Jan 2019, 12:48

I would not recommend doing a flush on a transmission that has presumably never been serviced and is this old. I think drain and fills are a safer way to go.

BryonTheCanadian · Post by **BryonTheCanadian** » 11 Jan 2019, 13:51

So please help me understand what is going with changing the fluids and the downsides of flushing etc .

Post by **Rattnalle** » 11 Jan 2019, 13:56

Worst case the new oil with fresh cleaning agents breaks some old stuff loose inside. Could happen but also easy to guard against with an inline filter if you're the paranoid sort.

Or if the tranny is in really bad shape the worn down clutches might still be in the oil in liquid form, helping what little of the clutches is left engage.

Likely? No.

XC70Rider · Post by **XC70Rider** » 11 Jan 2019, 15:07

When I got my 2007 XC70 with 121k miles last May I immediately did an ATF sump drain and added in 3.65 quarts of Mobil 3309. During the next oil change 3 months later I did another ATF sump drain followed with a return line drain. With the return line disconnected from RAD I'd start her up and shift until 1 quart flushed then replaced with new Mobil 3309. I did it 12 times to try and get it clean and red. With the return line disconnected I cut it and threw on a WIX 58953 magnetic in line filter.

During next oil change I'm doing another ATF sump drain and adding in 3.65 quarts of Idemitsu 10106042K ATF this time.

Post by **oragex** » 11 Jan 2019, 15:49

Just chinning in but the idea is clear: as everybody above, a few drains (that should be about 3.5L each) done a few months distance is the safest way. Using any 3309 oil (Toyota, Mobil 3309)

I did read of two situations when a full flush all at once on a high miles transmission that was driven mostly highway put an end to it. A transmission also has to adapt to new fluid (the solenoids will work differently) and as mentioned, there is already wear in clutches & other components so an abrupt complete fluid change may be a little too much for it.

My own experience at 170000km my newly purchased car was shifting quite smooth, I replaced 3.5L of the fluid (1 drain) just to be safe and surprisingly the transmission started shifting with little kicks in the first gears. So we never know.. but on the other side, at 250000km if it's already bumpy, I would suggest not to expect amazing results from fresh fluid: it may happen or may not. The idea is perhaps just to refresh a little the old fluid if you'll keep the car for another few years.

As for the Volvo dealer(s) the idea is simple: as Aisin told them (and to every other car maker that got their transmissions), this was a sealed for life transmission. Later on when they realized some solenoids were not designed accordingly and were starting to jam from old debris, Volvo kept saying no fluid change because by then it was already late (too costly) to admit the error. They also don't want to flush/drain fluids because the owner may come back with a broken transmission and blame it on the flush.