Thud when pressing accelerator

[prwood]

Its worth a shot, but the transmission level in the sump climbs when the engine is shut off, just like the engine.
It really needs to be checked per the procedure.

I don't get why the dipstick would even have a "cold" measurement range if it wasn't a valid form of measurement?

When was the last drain and fill?

I have records of the PO having the transmission flushed at the dealer at 67,619 and 98,217 miles. Between 98,217 when the PO stopped taking the car to the dealer for service (just a few oil change records at Sunoco after that), and 188,000 miles when I bought the car, I don't have any record of transmission service. I don't know what the PO may have done in terms of adding/removing/flushing fluid in that interim. From 187,000 until now (248,000) I know I haven't touched the transmission.

[abscate]

The definition of cold ATF is specified by the manufacturer but it isnt cold from sitting, its something like 80F, like after idling to warm engine.

Hot will be after a 30 minute hot run 150-180F

Peter - I would do three sessions of D&F on that puppy.

[prwood]

The definition of cold ATF is specified by the manufacturer but it isnt cold from sitting, its something like 80F, like after idling to warm engine.

Hot will be after a 30 minute hot run 150-180F

I get it now. And once it's running there would presumably be less oil in the sump and therefore a lower reading on the dipstick.

I guess they really don't intend for customers to check the transmission fluid, because this is all the owner's manual and service/warranty manual have to say about it:
- Use only Volvo Fluid Part # 1161540-8 @ volume of 7.5 liters
- Maintenance schedule says to inspect transmission fluid every 15,000 miles
* Note: Although the manual has a verbose set of instructions and specifications for checking the engine oil, there are no actual instructions on how to check the transmission fluid.

Peter - I would do three sessions of D&F on that puppy.

Would that basically equate to the same effects as a flush?

[RickHaleParker]

Would that basically equate to the same effects as a flush?

With Drain and Fill gravity does the work.

With a Flush, fluid is forced through the transmission under pressure. A Flush can dislodge too much crud at once and clog up the transmission. A Flush should only be used a preventive maintenance when the history of the transmission is known. A Flush should not be used as a repair method.

Think of a Flush as an internal power wash.

[prwood]

As I set out to measure the transmission fluid properly tonight, I found a few tidbits. VIDA has a fairly detailed description of the expected level on the dipstick at various temperatures, along with a handy chart:

TransmissionOilCheckConditions.png (59.13 KiB) Viewed 678 times

TransmissionOilTemperatureChart.png (40.59 KiB) Viewed 678 times

Here is the readout from VIDA of the conditions under which I did the check. I got the temperature up by idling in the driveway and shifting through the gears a few times.

And, perhaps hardest to interpret, here is the actual dipstick reading (I did this three times with the same results):

I'm seeing at least some amount of wetness just above the highest HOT line. But the thicker fluid seems to end somewhere between the top COLD mark and the bottom HOT mark. Going by the lighter fluid it seems like I'm in the right range, but going by the thicker fluid it would be too low.

Any thoughts?

[XC70Rider]

Just getting it warmed up from idling and manually shifting a few times in the driveway is only good for a COLD reading. To read it HOT you have to drive it through all 5 gears up to highway speed with a few stop and gos for ~30min.

Your fluid appears higher than average. Read the ATF where it's thick on the dipstick. The dipstick tube on my AT also leaves a small thin amount of ATF above the actual reading.

[RickHaleParker]

For a Transmission Oil temperature of 91° C, engine running.
I read that as below minimum. There is no Oil in the correct range.

Also noticed the engine temperature is ~ 10 ° C on the high side. You might want to check the fluid level right after a drive. This might bring the engine temperature down to 90° C and the Transmission Oil down to 80° C.

TransmissionFluidDipstick.jpg (494.26 KiB) Viewed 659 times

[prwood]

Here's the latest. I measured the fluid yesterday at midday, after the car had been sitting for 4 hours. It still measured up over the top of the HOT zone. I suctioned fluid through the dipstick tube until the mark was down to the level specified in VIDA:

At room temperature (+20 °C) the oil level is close to the MIN mark on the "cold area".

I measured 40oz or 1.18L of fluid suctioned.

I drove a few miles around town and observed that incidence and severity of the "thud" had decreased; however at first there were also a few shift flares. I assumed this was due to TCM trying to adapt to the sudden drop in fluid levels. By the end of my afternoon commute, this had smoothed out.

This morning I measured the transmission fluid again before starting the car for the first time, and the fluid was at the MAX mark on the "cold area", which is .2L higher than the above specified level from VIDA, but not enough for me to consider draining more fluid. I drove to work today and experienced a couple of "thuds" but not as much as in previous days. I also took the car out for a highway run of 30 minutes, and measured the transmission fluid afterwards using the procedure specified in VIDA (well, mostly, except I had to make an assumption about the temperature since my VIDA/DiCE rig is tethered at home):

...the "hot range" (+80 °C) is reached after approximately 30 minutes highway driving at an air temperature above +15 °C.

Park the car on a level surface.
Apply the handbrake.
Apply the foot brake.
Let the engine idle.
Move the gear selector lever to position P.
Move the gear selector through all positions. Wait in each position for approximately 3 seconds.
Move gear selector to position P and wait approximately 2 minutes before checking the oil level.
The dipstick must be pushed down as far as possible into the dipstick tube.

The level at this point was LOWER than when I measured first thing in the morning, and in fact just barely reached the tip of the dipstick. Based on this measurement, taking into account the distance between the MIN/MAX marks in the HOT area, I extrapolate that the dipstick is telling me the fluid level is low by approximately 1.5L, or in other words just slightly more than the amount I drew out the other day.

I am now faced with resolving some conflicting information:

1. "Thud" has decreased (but not disappeared) after drawing off ~1.2L of fluid.
2. Shifting performance seems at least as good, if not better, than before fluid was drained.
3. I have not measured the fluid temp with VIDA since drawing off the fluid, so I don't know whether I have traded apparently smoother performance for decreased cooling ability and eventual damage.
4. Fluid is around the expected level when cold according to VIDA, but fluid is WAY below expected level when hot, also according to VIDA.
5. Only the "hot" measurement is valid according to VIDA (and pretty much everyone on the forum), yet VIDA also has an expected level when cold. My prediction is that if I try to get the level into the correct range for "hot" then it will once again be above the correct range for "cold".

Further ponderings: Is the cold measurement completely useless, and if so why does the dipstick support it and why does VIDA mention it? Is all of the above moot anyway, since the fluid I'm testing with is old and dirty? Is this test only intended to be used after a fluid change?

Before my head explodes, should I just take Memorial Day Weekend off from worrying about the Volvo and drive the Sebring instead?

[gcha8e]

Nice family shot. I had my kids take a video of my mounts while pedal braking for me. I was able to see that my mount does not move nearly as much as yours did. I checked the lower torque rod too, and it seemed to be holding up even though close inspection appears to show some pretty cracked out rubber - it's hanging in there. Your other videos have inspired me to check my transmission fluid. Just because I've been curious. It does seem that Volvo doesn't want you to do anything to the trans fluid. The maintenance schedule I recall looking at when I first got the car showed no fluid replacement at any point. I suppose it's just a "let the car tell you what it needs" sort of thing?

[abscate]

You want to do drain and fills so you can see what comes out of the sump. There might be a fair amount of crud first time; do not freak.

It will dump about 4 liters on draining with engine shut off hot. Replace with 3.5 cold and then warm it up, then check / adjust level.

Three drain and fills with a week driving in between will replace 90% of your ATF

Repeat about every 15000 miles. This will mean you are replacing your ATF every 50000 , roughly.