Transmission Drain and Fill Question

So I bought my truck at approx 110k miles and it just hit the 120k mark. On the carfax it jumps from about 47k until I bought it. Obviously I don't want to just assume the person before me kept up with everything so should I have a drain and fill done or is it too risky at this point, not knowing if the 60k d/f was done?

I know a flush is a terrible idea but what about a simple drain and fill?

 

I doubt it would hurt anything.

 

Nothing to worry about, drain and fill will be ok.

 

Alright cool, I heard both and people saying drain and fill could still kick stuff up and mess up the trans so I just wanted to double check. Thanks guys!

 

Pull the dip stick out and see if the fluid is clean, dark or burn b4 doing anything

 

I'd drain and fill it three times over about the next 6k. You have no idea what they might have been doing with the truck. Might also want to reset the fluid degradation meter in the computer using techstream software to get the clutch pack pressures matched up with the fresh fluid. After that has been reset I'd do one more drain and fill. Ounce of prevention is worth a pound of cure.

 

What’s all this about?? I’ve never heard of that fluid degradation meter topic before

 

I read about it in this forum. Apparently the computer compensates as the fluid degradation occurs over time. Basically, my understanding is that it makes pressure adjustments to the clutch packs. Makes sense to me.

 

make sure your fill bolt comes out before draining lesson learned the hard way...

 

I thought the ATF fluid degradation meter was just an info only readout to provide a measure regarding cumulative ATF high temp exposure for follow-up on tranny problems. I don't know that it figures into any trans control strategy. I do not have a Techstream or clone so could not reset it when I changed the ATF. Did not worry about it as I didn't think it controlled anything. Can someone verify?

 

If there is a dipstick for the ATF on his truck there are much bigger issues. In my experience WS turns dark fairly quick so color isn’t a great indicator. If it was me, I’d do drain and fills every 10k for the next 40k miles assuming you plan on keeping the truck as long as possible.

 

So when you say to do it every 10k for next 40k are you talking about full drain and fills? I've never done one but from my understanding from the forums is you don't actually drain out all of the fluid but rather only end up putting in 3-4 new quarts each time?

Also not sure about the whole techstream clutch pressure packs thing, hadn't heard that before. Is that something that could be done at a dealer?

 

https://youtu.be/cNu3feOLXxI
look very easy, I spend more time hunting for parts then doing the actual work

 

Right - you’ll drain about 4 qts each time which is approx 1/3 of the total fluid. Ideally drains 3 and 4 will look about the same. Try to take pics of the old fluid on a paper towel in the same lighting conditions for comparison.

 

Is that all it will allow me to drain or that is all I should drain? Certain parts of cars I've always let a shop handle and trans is one of them so my knowledge is miniscule lol don't wanna jump in there accidentally drain everything

 

That is all it will allow from the drain plug in the pan

 

And is there a fill line? How do you know how much to put back? Or is it like diff and just filler up?

 

There’s a overfill plug next to the drain plug, the filler plug is on the transmission

 

^ This. If you have an ATF cooler, there is a method that unhooks the return line and allows you to pump out 2 quarts at a time getting much more than the 4 quarts but it is much more involved and carries more risk for a DIY'er in my opinion.

2 methods people use - 1) measure what you take out and replace the same volume. The old and new fluid should be approx the same temperature if you use this method. 2) the "proper" way is to get the transmission to a specified temp (around 100F) and pull the check bolt - you should get just a trickle of fluid with the motor running. If it doesn't trickle, its low. If its more than a trickle, its high and you keep the check bolt out until it slows to a trickle. Spend some time reading some relevant threads on here and it will make sense.

 

Gotcha. Thanks. Yeah, need to read up on it. Was done at dealer last so I have no idea if it’s the right level.

 

great video, guy is on point...

 

Unhooking the return line is a simple process. I’ve done it on two different trucks. Easy peasy.

 

I was looking at the lines going into the transmission cooler yesterday

Which line is it? I see on the metal lines that run over the radiator shroud and it looks like they have red and blue marks where they attach into the transmission cooler

 

Question answered today

Here’s pics as proof

The 1 with fluid in it is the winner!