8 speed fluid change-level the truck or level the trans?

[AmosMoses]

So really there are two methods. The stellantis version mentioned above that has the wheels spinning and the ZF one that has you set the brake and go through the gears, holding them in gear for 10 seconds each.

Is this correct?

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[Hootbro]

So really there are two methods. The stellantis version mentioned above that has the wheels spinning and the ZF one that has you set the brake and go through the gears, holding them in gear for 10 seconds each.

Is this correct?

Basically correct. I have done the latter of just running and holding them through the gears for a few seconds and the vehicle staying static.

 

[ShadowsPapa]

Basically correct. I have done the latter of just running and holding them through the gears for a few seconds and the vehicle staying static.

They accomplish the same thing. The one being safer

 

[Maximus Gladius]

No one does that.

I do. Don’t tell anyone. I typically practice what I say, most times.

 

[ShadowsPapa]

I do. Don’t tell anyone. I typically practice what I say, most times.

I have 4 HD NAPA jack stands, identical.

I figure if the thing is lifted sitting on my stands, and I count how many clicks each stand is up, and they are on the bottoms of the frame rails and not anything else, then it will be lifted exactly as a 2 post lift would do it. It would mimic a 2 post lift with 4 pads on the frame.

 

[Maximus Gladius]

I have 4 HD NAPA jack stands, identical.

I figure if the thing is lifted sitting on my stands, and I count how many clicks each stand is up, and they are on the bottoms of the frame rails and not anything else, then it will be lifted exactly as a 2 post lift would do it. It would mimic a 2 post lift with 4 pads on the frame.

Right, so your identically set stands are only as level as the ground is. I can’t do that with my garage floor and call it level.

I have to use a long level because my floor has a difference of 3” over 17’ (front to back) and about 1-1.5” difference over 5’(side to side).

I can’t in all good conscience just set each stand the same and call it good enough. If I’m making the effort in the first place, it may as well be done right, especially for those reading this thread that have OCD and other similar “extra abilities”.

 

[Maximus Gladius]

Would absolutely love to read your email that’s all fuzzy in you post! Is that something you would share with us?

 

[AmosMoses]

Right, so your identically set stands are only as level as the ground is. I can’t do that with my garage floor and call it level.

I have to use a long level because my floor has a difference of 3” over 17’ (front to back) and about 1-1.5” difference over 5’(side to side).

I can’t in all good conscience just set each stand the same and call it good enough. If I’m making the effort in the first place, it may as well be done right, especially for those reading this thread that have OCD and other similar “extra abilities”.

Which is why ZF should clarify given that the transmission is mounted to a multitude of chassis. The trans pan mounting surface should be ground zero for level especially if the pump is that susceptible to premature wear from oil starvation.

 

[Hootbro]

Which is why ZF should clarify given that the transmission is mounted to a multitude of chassis. The trans pan mounting surface should be ground zero for level especially if the pump is that susceptible to premature wear from oil starvation.

At the end of the day, you are not ZF's customer, the vehicle maker is and they are going to defer to those instructions when there is a conflict between the two.

 

[Maximus Gladius]

What we do know is the cause and effect of what we’ve done and the results that come from it. Vagueness aside, my practice has been to have level frame, back wheels on the ground as @Hootbro also does, nothing spinning, run the gears with brake on, get to desired temp, make fluid adjustments and be done.

Watching temp and listening for whine afterwards are indicators you did right or somethings not right. Stay the course and repeat for next time or make immediate adjustments.

There’s flexibility in procedure, papers posted by @Hootbro show wheels spinning (in part) and brakes applied (in the other part).

Ive done 7 pan drops between 2 transmissions. I’ve had the ass end way up as OP has, I’ve levelled the frame and had wheels spinning and I’ve had back wheels down, static (this last method is safest). I finish the running of the gears and fluid level at 32c (89F) and this transmission runs 30F cooler than engine/coolant temps. Something has worked out well.

 

[ShadowsPapa]

There's enough fluid, it's not going to starve. You'll hear it when it's cold if it's low.

 

[ShadowsPapa]

and this transmission runs 30F cooler than engine/coolant temps. Something has worked out well.

That is truly strange. But then, it's very unlikely anything a person does during a fluid change will impact that. (I almost suspect there's a sensor error or something else going on)
There's just nothing you are going to do with fluid levels to make it run cooler or hotter - other than starve it for fluid, and that will result in pump whine and damage.

It's another thing that's being picked to pieces and almost to death, with so many "but what if's " thrown in, it's like the battery discussions.
Just follow the video or the FCA instructions and call it good, you aren't going to do anything superior or earth shatteringly better or outsmart them.

 

[Maximus Gladius]

There's just nothing you are going to do with fluid levels to make it run cooler or hotter

I may have to shoot the tranny in various places with my laser thermometer to see if the dash data communicates what the gun says. I don’t believe playing with the oil levels have dropped my temps. I do believe it’s from the 4 pan drops I’ve done since getting this current transmission. As I’ve said before, several times, I didn’t see any significant temp drop until the 3rd pan drop and then back in April when I did my 4th drop, I saw 3 significant temp drops through the summer.

So it’s either a faulty sensor as you said (and I’ll check) or maybe it’s just keeping the fluid fresh and not letting the effects of oxidation do what it does. If my test show there’s nothing wrong with the temp sensor then you probably shouldn’t poo hoo or be a neigh sayer to the effects I see from multiple pan drops. Your life long career experience with transmissions have never travelled this road so all you or everyone else can do is just take note of the data and think that maybe doing what I’ve done has been a positive thing. If it lives longer than “normal” or I prove I don’t have to live on pins and needles when approaching its 60k warranty life, well, we aren’t there yet.

edit: 60k warranty applies to every still on original tranny. I’m on my 4th so warranty was done soon after I got that one.

 

[Maximus Gladius]

Can someone point me to where the temperature sensor is on this transmission?

 

[Stan H]

Can someone point me to where the temperature sensor is on this transmission?

Give me a minute

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