Paranoid - Did my mechanic fill my ATF correctly?

WHEN your trans shifts up or down is controlled by the ECU electronically. Has NOTHING to do with fluid. HOW it performs the shift or how well it hangs on to the gear can be influenced by fluid.

 

Once you've confirmed the correct amount of fluid is in there from the start, you can absolutely just drain and add back exactly what you drained. I probably wouldn't do it on a warm transmission.

For me, to bother with measuring out everything and getting it "exact", it is about the same amount of effort as just draining it, filling it and then doing the check plug procedure.

 

Since mine is a 2019 with no cooler - I assume the only part is checking the overfill after it reaches temp? No pinning?

 

Right - and the temp is when the ATF is 99 degrees in the pan so you need a way to monitor that from the sensor.

 

Correct no pinning if you have no thermostat to pin. I l myself did the add back what drains out because at first the check procedure sounded complicated. Then I decided to try it and realized its actually easier to do the check procedure than to measure out the fluid. Once you do it once you'll only get faster at it.

 

You do not have a thermostat to pin. So you are correct.

 

He had the truck for 2 hours. Would that have even been enough time to get it lowered to temp?

 

Doubt it. He probably measured and replaced same volume.

 

When I did mine on the 30th, my temps were still in the lower 110's after 3 hours of sitting. I don't know the temp when I parked it but I had come home from work, ~30 min highway drive. So, likely around 180-190 degrees.

After 4 hours it was at low 90's and I was able to drain and fill. You do lose a small amount of heat with drain and fill since you will be adding ambient temp fluid to the pan.

Now, he could have thrown a fan on it. Not sure if it would really drop the temp that fast though.

 

This is one of the reasons I'm skeptical about a shop drain and fill. I just do not see any tech waiting very long for the temp to stable. Drain and fill what exactly what comes out.

The only ones that will follow the procedure exactly are those of in this thread that want to do it that way. ( Not me)

 

I’m bringing it to a dealer tonight to do another drain and fill. They said they need to let it sit overnight to do the full process and check temps, etc. and seemed very familiar with the process for checking it.

I’ll be out another $200 but it’s a lesson learned and I guess it won’t hurt to get some more of the old fluid changed out. I should have pressed the other shop more about it.

 

that’s no good right?

 

In theory - the fluid expands when hot. So if you go by volume you could over fill using room temp fluid off the shelf as equal volume. Is it enough to make any difference - I highly doubt it.

I think it would be more of a problem if you pull the check plug while the trans is at full temp - you’d end up draining more fluid than you should and could make it low.

 

I’ve always been curious how much this fluid expands. I can’t imagine it increasing by more than an ounce or so.

I’m no expert though.

 

I’m so torn if I should bring it to the dealer for another drain and fill so I can have some peace of mind it’s been leveled according to Toyotas way

 

If it was me, I would just check your fluid at the right temp (or close) and see where it’s at. Or the truck me smooth itself out too with the new fluid.

If you do go and have another D/F done, at least you’ll get more of the old fluid out.

There’s plenty of DIY tutorials on how to do it though if you wanted to save the money and do it at home.

 

Just dropped it off at the dealer. They need it overnight to cool off so they can do it right and check the temp. I called my independent and asked why they were able to do it in an hour while hot, and he said “that’s just how we do it”. Not sure who’s right but I feel comfortable with the dealer stating it needs to be cool so it can be checked at a specific temp.

 

Thats just how we do it translates to we really don’t give a sh!t about the right way, just the fast way. Shows a total lack of competence and ethics and should be your cue to find a better shop. Its ok if a shop doesn’t follow procedures as long as they tell you that along with a rationale for their different approaches. Often factory procedures are overly conservative and short cuts are acceptable. In this case, it is no good. They mAy be over filling it a bit which is fine, but they may be just measuring what came out and match, assuming the previous person was more competent and did it correctly.what if the last shop was even more incompetent and under filled it by 2 quarts? You can see what the chain of laziness and incompetence can lead to.

 

It's that and a few other reasons that I, like many others here, have decided to take the ownership of maintenance for our vehicles/equipment.

It is not glorious work and most days, I would rather not do it at all. But, I know that if I do it, following the documentation from the manufacturer, I can get it done and done right!

 

I do wish I was a bit more mechanically inclined. It’s tough to find the time to do it!

 

Is an ATF exchange (which my Toyota dealer does for me and I believe is a good price considering it’s all new fluid) the same as a flush? If not, how is a flush different?

 

Drain and fill, taking out what’s in the pan