Bad shifting after transmission fluid flush

[FireFox31]

Yes, you all told me so. I'm experiencing a shift flare between 2nd and 3rd after flushing transmission fluid out of the cooler line on old Geronimo. Do you think the shift will smooth out over time?

TL;DR:
The 2000 V70 has 360k miles, had leaking repaired transmission fluid hoses, and an unknown quantity, quality, and age of the fluid. The fluid was filthy black and full of grit. Yet, the car shifted quickly and firmly.

I did a drain/fill and drove it 500 miles. Today, I drained and replaced the 4 quarts, then ran 2 quarts out the cooler line and replaced it three times, pushing 6 quarts through. I finished by removing 1.7 quarts until the level was at cold max on the dipstick.

The shift flare occurs under moderate to hard acceleration. 2nd gear releases but 3rd doesn't engage until half a second later, revving the engine during that time. There was even a little revving when manually shifting between L and 3.

All other shifts are now softer than they were. I'm not sure what's normal but the fast, crisp shifts before the change seemed a little odd. Thanks for any input.

[xHeart]

A counter reset is recommended after ATF flush. The normal drive cycle will smooth it out, unless you have failing ETM.

[V50M66]

Power flushing these transmissions using an external machine is quite possibly the worst thing you can do to them, and ruins more transmissions than it helps. You couldn’t pay me enough money to go near one.

Resetting the fluid counters in VIDA and doing the adaptation should help, but I wouldn’t hold your breath that it’ll completely go away.

My question is, if it was shifting fine before, why mess with it, especially in such an invasive way? Nothing wrong with a couple drain and fills, or flushing it using the internal pump and the cooler lines, but those flush machines are a great way to blow out seals and otherwise ruin your transmission

Edit - it’s since been clarified that this is not the method the OP used, so the info about power flushing using a machine can be disregarded for this discussion. However, if any future readers have this issue after a machine flush, now you know why

[Krons]

My kids 02 S60 shifted funky after a cooler return flush but eventually settled down and now shifts fine. Maybe time will help it relearn and improve.

[FireFox31]

Thanks, I'll reset the fluid counter.

Power flushing these transmissions using an external machine is quite possibly the worst thing you can do to them, and ruins more transmissions than it helps

Sorry, I used the wrong terminology and edited my original post. I flushed the transmission by disconnecting the cooler return line and running it until two quarts had been removed, added two quarts, repeat.

I was a little aggressive with the flush by accelerating the car to actually shift through all gears since the 4/3/L shifter doesn't actually shift it. I really wanted to get out all the old fluid which was in terrible condition and likely the wrong type. It was tough to accelerate and stop before expelling two quarts of fluid.

Here is what the fluid looked like at the various stages. When stirring my little sample cups with a screwdriver, I swear I feel grit in the original and drain/fill fluids. The drain plug magnet was completely covered upon the first drain and had accumulated more after the first drain/fill.

[V50M66]

Thanks, I'll reset the fluid counter.

Power flushing these transmissions using an external machine is quite possibly the worst thing you can do to them, and ruins more transmissions than it helps

Sorry, I used the wrong terminology and edited my original post. I flushed the transmission by disconnecting the cooler return line and running it until two quarts had been removed, added two quarts, repeat.

I was a little aggressive with the flush by accelerating the car to actually shift through all gears since the 4/3/L shifter doesn't actually shift it. I really wanted to get out all the old fluid which was in terrible condition and likely the wrong type. It was tough to accelerate and stop before expelling two quarts of fluid.

Here is what the fluid looked like at the various stages. When stirring my little sample cups with a screwdriver, I swear I feel grit in the original and drain/fill fluids. The drain plug magnet was completely covered upon the first drain and had accumulated more after the first drain/fill.

Ah, in that case disregard what I said about power flushing as it doesn’t apply here.

It’s possible that there was so much friction material suspended in the fluid that it was helping the clutches engage, and now that it’s not there, it’s not as grabby so it behaves differently. This is somewhat common with high mileage transmissions that receive a fluid change after never having had a prior service, and the reason people say to not change the fluid if you have a high mileage vehicle that’s never had a change before.

However, you’re just experiencing shift flares and no slip once in gear, correct? If so, it’s pretty likely that resetting the fluid counters, resetting adaptations, and then driving the car to allow it to learn itself with the new fluid will take care of your issue, at least most of the time.

[abscate]

Nice and patient with those drain and fills. Try to be gentle with that right foot, too.

[jreed]

I really like the paper towel fluid color 'map' / 'graph'. That's a great idea! I'm looking forward to trying that for myself the next time I change the ATF.

[FireFox31]

I don't think the clutch is slipping at all when driving. I noticed the tachometer bob a little when I took my foot off the gas. My poor G70 with its horrible transmission fluid has that problem terribly, perhaps the torque converter locking and unlocking constantly. That's why I was so hyper aware to notice it.

I don't think I'll reset the adaptions. I read old MVS posts about it and the consensus was to only reset them when a part of the transmission is changed. The car is driven a lot (though almost entirely at highway speed) so I hope it relearns in a week or two. I'll put it through a test run after that and see how it does.

I saved a small sample of fluid from each stage of the flush in little restaurant sauce take out containers. I should have added a strip for new unused fluid but my 11 other bottles are sealed. The paper towel visualization was a quick way to show the fluid color. I wish I had a transparent film over a light box to really show it. Or even white plastic which wouldn't absorb to help show the color (the firm paper I used was too absorbent). I saved the cups to get samples when I flush the lethally bad G70 transmission.

Promotional consideration for the fluid test goes to Dunkin Donuts, who provided the box I cut as a background. I stopped in during my test drive... at 5:30 am after working all night on the transmission. It took me 13 hours to replace an axle, replace a stuck trans fluid line, and do the flush though every step went smoothly.

[V50M66]

If the fluid was that bad, I’d reset the counters at the very least. Being that it was so bad, I would consider resetting the adaptation. I was also worried the first time I did it, but the improvement after a couple drive cycles was very notable