8HP75 Transmission Fluid Change

[popcenator]

I'm not quite sure what you're question is??

My question is, wouldn't you want to check the fluid level at the lower end of the temp range, because the slope of the transmission and the front end being leveled out (in my case)? The angle of the transmission increases over stock with a leveling kit on it, meaning the fluid is pushed further back in the pan than it is at stock height. Even at stock height, since the transmission isn't level, wouldn't you want more fluid to make up for the slope?

This would explain the instructions you've posted stating that you want to make sure the temp is below 86 before doing the procedure which should result in a higher fluid amount making up for the fact that when all 4 tires are on the ground, the transmission is sloped to the rear and fluid sits toward the back of the transmission. Every other set of instructions including from ZF's website say to wait until the fluid temp is in the 86-122 range before starting the procedure.

 

[Wild one]

My question is, wouldn't you want to check the fluid level at the lower end of the temp range, because the slope of the transmission and the front end being leveled out (in my case)? The angle of the transmission increases over stock with a leveling kit on it, meaning the fluid is pushed further back in the pan than it is at stock height. Even at stock height, since the transmission isn't level, wouldn't you want more fluid to make up for the slope?

This would explain the instructions you've posted stating that you want to make sure the temp is below 86 before doing the procedure which should result in a higher fluid amount making up for the fact that when all 4 tires are on the ground, the transmission is sloped to the rear and fluid sits toward the back of the transmission. Every other set of instructions including from ZF's website say to wait until the fluid temp is in the 86-122 range before starting the procedure.

I think you're misreading the the instructions,as i've never seen any that say "wait" till the transmission is between 86 and 122 before "starting" the procedure,the ones i've seen say to check the fluid level between 86 and 122,and as long as it dribbles out of the fill hole you're good.
Step 5 tells you to start with the transmission below 86F
Read the highlighted paragraph after step 12,it says to check the fluid level "between" 86 and 122,and if you start with the transmission above 86,there's a good chance it'll have exceeded the max temp of 122 by the time you've completed the procedure,and got back under the truck to do the final check. If you're worried about it being down on fluid because of your level kit,you could always jack the rear tires farther off the ground,so the transmission has a very slight downhill run to the front when you do the level check.

 

[DILLIGAF]

I did the procedure, by the time I was done, temps were bang one. So no need to overcomplicate things.

 

[popcenator]

I think you're misreading the the instructions,as i've never seen any that say "wait" till the transmission is between 86 and 122 before "starting" the procedure,the ones i've seen say to check the fluid level between 86 and 122,and as long as it dribbles out of the fill hole you're good.
Read the highlighted paragraph after step 12,it says to check the fluid level "between" 86 and 122,and if you start with the transmission above 86,there's a good chance it'll have exceeded the max temp of 122 by the time you've completed the procedure,and got back under the truck to do the final check. If you're worried about it being down on fluid because of your level kit,you could always jack the rear tires farther off the ground,so the transmission has a very slight downhill run to the front when you do the level check.

I'm not misreading anything. Step 5 clearly states to verify the transmission temp is below 86 and then to start the procedure. Meaning the shift procedure. I know you should be checking the fluid for a trickle once it's in the temp range, I'm talking about the actual shift procedure. I can start the shift procedure when the transmission temp is in the 70s and be done with the procedure before it even hits the window, and get a trickle in the upper 80s if I tried. That would result in more fluid in the front part of the pan. When you put the truck back on the ground, the front part of the pan could be low on fluid when the transmission is colder and the rear part of the pan higher because of the rear slope. I've done this procedure more times than I can count, experimenting with leveling at the the lower part of the temp range vs the higher part of the temp range and my transmission always shifts better when I get a trickle in the high 80s to low 90s than it does near 115 or so, especially when the transmission is cold which leads me to believe the transmission might be low on fluid when it's colder due to the slope as the fluid is pulled out of the pan to circulate. Once the fluid warms up and is circulated, its no longer low because it has expanded and is circulating.

 

[joesstripclub]

My question is, wouldn't you want to check the fluid level at the lower end of the temp range, because the slope of the transmission and the front end being leveled out (in my case)? The angle of the transmission increases over stock with a leveling kit on it, meaning the fluid is pushed further back in the pan than it is at stock height. Even at stock height, since the transmission isn't level, wouldn't you want more fluid to make up for the slope?

This would explain the instructions you've posted stating that you want to make sure the temp is below 86 before doing the procedure which should result in a higher fluid amount making up for the fact that when all 4 tires are on the ground, the transmission is sloped to the rear and fluid sits toward the back of the transmission. Every other set of instructions including from ZF's website say to wait until the fluid temp is in the 86-122 range before starting the procedure.

I'm not misreading anything. Step 5 clearly states to verify the transmission temp is below 86 and then to start the procedure. Meaning the shift procedure. I know you should be checking the fluid for a trickle once it's in the temp range, I'm talking about the actual shift procedure. I can start the shift procedure when the transmission temp is in the 70s and be done with the procedure before it even hits the window, and get a trickle in the upper 80s if I tried. That would result in more fluid in the front part of the pan. When you put the truck back on the ground, the front part of the pan could be low on fluid when the transmission is colder and the rear part of the pan higher because of the rear slope. I've done this procedure more times than I can count, experimenting with leveling at the the lower part of the temp range vs the higher part of the temp range and my transmission always shifts better when I get a trickle in the high 80s to low 90s than it does near 115 or so, especially when the transmission is cold which leads me to believe the transmission might be low on fluid when it's colder due to the slope as the fluid is pulled out of the pan to circulate. Once the fluid warms up and is circulated, its no longer low because it has expanded and is circulating.

You are talking about the transmission angle and not misreading the instructions, when you clearly missed step 1 to level the transmission. I think leveling the transmission is going to be a much larger factor to ensure you have the proper amount of fluid than the difference 20 degrees would make on the fluid expansion.

 

[popcenator]

You are talking about the transmission angle and not misreading the instructions, when you clearly missed step 1 to level the transmission. I think leveling the transmission is going to be a much larger factor to ensure you have the proper amount of fluid than the difference 20 degrees would make on the fluid expansion.

I'm very aware you level the pan to check the fluid, that's why I mentioned it in my post yesterday, so I didn't miss anything.

 

[Wild one]

I'm not misreading anything. Step 5 clearly states to verify the transmission temp is below 86 and then to start the procedure. Meaning the shift procedure. I know you should be checking the fluid for a trickle once it's in the temp range, I'm talking about the actual shift procedure. I can start the shift procedure when the transmission temp is in the 70s and be done with the procedure before it even hits the window, and get a trickle in the upper 80s if I tried. That would result in more fluid in the front part of the pan. When you put the truck back on the ground, the front part of the pan could be low on fluid when the transmission is colder and the rear part of the pan higher because of the rear slope. I've done this procedure more times than I can count, experimenting with leveling at the the lower part of the temp range vs the higher part of the temp range and my transmission always shifts better when I get a trickle in the high 80s to low 90s than it does near 115 or so, especially when the transmission is cold which leads me to believe the transmission might be low on fluid when it's colder due to the slope as the fluid is pulled out of the pan to circulate. Once the fluid warms up and is circulated, its no longer low because it has expanded and is circulating.

Well if you have it figured out,why are you asking me.Now you appear to want to argue about something,i don't think is worth arguing over. As long as you're between 86 and 122,you should be good to go,and if you find your transmission works better when you check it at 86 instead of 122,by all means check it at 86F then,as you're still with-in the temperature window of checking the fluid.
I'm still not really grasping your question,other then you think your level has something to do with the temp you should be checking it at,and i hate to say anything,but that's beyond my pay grade,so check it at the temp you've found to work for you,whether thats at 86F or 122F,or any temp between those 2 numbers

 

[popcenator]

Well if you have it figured out,why are you asking me.Now you appear to want to argue about something,i don't think is worth arguing over. As long as you're between 86 and 122,you should be good to go,and if you find your transmission works better when you check it at 86 instead of 122,by all means check it at 86F then,as you're still with-in the temperature window of checking the fluid.
I'm still not really grasping your question,other then you think your level has something to do with the temp you should be checking it at,and i hate to say anything,but that's beyond my pay grade,so check it at the temp you've found to work for you,whether thats at 86F or 122F,or any temp between those 2 numbers

Lol I really don't understand the hostility here. I'm asking questions, and asking you specifically because I respect your insight. I know you know a lot about this stuff. I'm not questioning your knowledge at all, just asking questions that I have not seen anyone really mention, no need to get defensive. It's really become difficult to have a discussion anymore without someone getting bent out of shape. I'm only seeking knowledge from someone who I know has a lot of it, that's all. What's the point of a forum if you can't ask questions? I'm in no way insinuating that you don't know what you're talking about, it's completely the opposite, I'm trying to learn from someone who has a ton of knowledge.

All I'm asking is that, when you're transmission is raised up in the rear to get the pan level, wouldn't you want the fluid to be trickling closer to the 86° range as opposed to the 122° because when you lower the truck back down to the ground your transmission is sloping towards the rear of the truck. This means the fluid is higher at the rear of the pan than it is at the front of the pan, meaning when the transmission is colder there's a lower fluid amount at the front of the pan, so having the fluid trickling out closer to the 86° range means that when your transmission is colder your fluid is still level. Once the truck warms up and the fluid expands it's not so much a big deal.

 

[DILLIGAF]

Your looking into this way to much dude... Just follow the instructions.

Wonder where the trans fluid is when im on the side of a cliff at 8000ft Pretty sure ZF figured it out angles and how the pump works.

 

[Wild one]

Lol I really don't understand the hostility here. I'm asking questions, and asking you specifically because I respect your insight. I know you know a lot about this stuff. I'm not questioning your knowledge at all, just asking questions that I have not seen anyone really mention, no need to get defensive. It's really become difficult to have a discussion anymore without someone getting bent out of shape. I'm only seeking knowledge from someone who I know has a lot of it, that's all. What's the point of a forum if you can't ask questions? I'm in no way insinuating that you don't know what you're talking about, it's completely the opposite, I'm trying to learn from someone who has a ton of knowledge.

All I'm asking is that, when you're transmission is raised up in the rear to get the pan level, wouldn't you want the fluid to be trickling closer to the 86° range as opposed to the 122° because when you lower the truck back down to the ground your transmission is sloping towards the rear of the truck. This means the fluid is higher at the rear of the pan than it is at the front of the pan, meaning when the transmission is colder there's a lower fluid amount at the front of the pan, so having the fluid trickling out closer to the 86° range means that when your transmission is colder your fluid is still level. Once the truck warms up and the fluid expands it's not so much a big deal.

Pour some fluid in a measuring cup then,check the level in the cup at 86F,then slowly heat the fluid to 122 and see how much the fluid level changes.
There's no hostility except from you.Hell i didn't even understand what you were asking on your first couple of posts,as they were a bit misleading
If you find your transmission works better when checked at 86F,check it at that temp and carry on.
And quit trying to create an arguement ,when there's nothing to argue about
Nobody knows your truck better then you,and if you find a temperature to check the fluid level at,that it likes and is with-in the temperature window,check it at that temp and carry on

 

[joesstripclub]

All I'm asking is that, when you're transmission is raised up in the rear to get the pan level, wouldn't you want the fluid to be trickling closer to the 86° range as opposed to the 122° because when you lower the truck back down to the ground your transmission is sloping towards the rear of the truck. This means the fluid is higher at the rear of the pan than it is at the front of the pan, meaning when the transmission is colder there's a lower fluid amount at the front of the pan, so having the fluid trickling out closer to the 86° range means that when your transmission is colder your fluid is still level. Once the truck warms up and the fluid expands it's not so much a big deal.

If I had to guess, I think the temperature range for the fluid check has less to do with the expansion of fluid and more to do with all the thermostats being open and flowing and the valve body full. If I understand what you are asking, you are trying to say that you will have more fluid if you check it while cold because the fluid has experience less expansion. While yes thats true, that effect is negligible once you are back on the ground and start driving. Starts and stop are going to create way more sloshing than that fluid can ever expand. The transmission doesn't need a precise amount of fluid just in the operating range.

 

[popcenator]

The whole point of me asking the questions, is to maybe understand my own transmission a little better. From my experience with testing the check at different temperatures, the shifting behaves very differently when the trickle happens at the end of the window than it does at the beginning of the window. I've been trying to understand why the shifting in my truck is clunky and sloppy when it's cold and I've leveled the fluid at the higher temp, and thought maybe it has something to do with the fact that the fluid is lower when it's colder because it's thinner and it's being pulled from the pan. When the transmission warms up and starts completely circulating it's better because the fluid has expanded enough. I don't know why asking questions equates to arguing, I'm just trying to get to the bottom of a slight issue I'm having and maybe trying to help those who have the same experience. I never once said anyone was wrong, just tried to ask follow up questions in case it hadn't been thought of in that way. Maybe my truck is just weird like that, who knows.

 

[Wild one]

I think Joe pretty well covered it,the expansion factor isn't going to compensate for the slosh factor.
If you really want to know how much the fluid expands,do the measuring cup test i pointed out to you,that'll let you know how much fluid expansion actually happens between 85 and 122

 

[popcenator]

Well, I appreciate everyone's contribution on this, didn't mean for it to turn into what it did, just trying to get to the bottom of an issue I'm having. I don't know why my truck has to be so wonky but it is what it is. It's been doing this since before I started checking the level and I've brought it into the dealership multiple times for them to check it out and of course they state it's normal behavior. It's been 5 years now so it is what it is at this point.

 

[joesstripclub]

Well, I appreciate everyone's contribution on this, didn't mean for it to turn into what it did, just trying to get to the bottom of an issue I'm having. I don't know why my truck has to be so wonky but it is what it is. It's been doing this since before I started checking the level and I've brought it into the dealership multiple times for them to check it out and of course they state it's normal behavior. It's been 5 years now so it is what it is at this point.

Have you tried to do a transmission learn reset? Also look at the temps of the transmission next time it is acting funny vs shifting properly and maybe that will give some other indication what's going on. A transmission with extremely cold fluid will generally shift a bit firmer, but once you are starting to warm up it should even out. You said you have changed your fluid before, what fluid did you use? And did you do a couple changes to get all the old stuff out?

 

[popcenator]

Have you tried to do a transmission learn reset? Also look at the temps of the transmission next time it is acting funny vs shifting properly and maybe that will give some other indication what's going on. A transmission with extremely cold fluid will generally shift a bit firmer, but once you are starting to warm up it should even out. You said you have changed your fluid before, what fluid did you use? And did you do a couple changes to get all the old stuff out?

I've done a reset a couple times (unplugging the battery for a while) and it'll shift ok for a few days then go back. I also think the adaptive programming isn't the greatest on my truck. The worst shifting is when the transmission is colder. Right now the transmission usually sits in the 60s at first startup because it's cooler out, so until it warms up, the shifting is a little clunky. The more fluid I leave in it when I do the fluid checks, the earlier it starts shifting normal which sparked these questions. Like Wild one pointed out, nobody knows my truck better than me so if leaving more fluid in it alleviates the problem then do so. I haven't completely changed the fluid, just checked it a multitude of times so I've drained and filled quite a bit. Just asking questions to see if maybe the reason why it's so clunky when it's colder is because at colder temps, the fluid is lower than it should be in my case.

 

[Jas34]

If the actual issue is that you have a shifting problem, then you likely have a transmission problem, and no small difference in fluid level should change this. If it's been going on for 5 years, then it probably isn't terminal anytime soon.

The bigger question I would have is why bother checking the level as much as you are. It's sealed, and if it isn't leaking anywhere, the level hasn't changed since it was last filled. I might instead change the fluid a couple of times or so to increase the amount of new fluid in the transmission to see if that makes any difference in the shifting. I would also question what has been used in it for fluid the last time it was serviced.

"Clunky and sloppy" is kind of vague. I don't know much about how Ram programs their transmissions, but it's common for manufacturers to raise shift points on a cold vehicle to warm it up to operating temps quicker. That definitely changes the feel of the shifts, so what you're experiencing could be normal operation.

 

[joesstripclub]

I've done a reset a couple times (unplugging the battery for a while) and it'll shift ok for a few days then go back. I also think the adaptive programming isn't the greatest on my truck. The worst shifting is when the transmission is colder. Right now the transmission usually sits in the 60s at first startup because it's cooler out, so until it warms up, the shifting is a little clunky. The more fluid I leave in it when I do the fluid checks, the earlier it starts shifting normal which sparked these questions. Like Wild one pointed out, nobody knows my truck better than me so if leaving more fluid in it alleviates the problem then do so. I haven't completely changed the fluid, just checked it a multitude of times so I've drained and filled quite a bit. Just asking questions to see if maybe the reason why it's so clunky when it's colder is because at colder temps, the fluid is lower than it should be in my case.

If I were you, unless you plan to take it in to the dealer under warranty, you might consider sourcing some fluid and a new pan and change the fluid. Drive it a couple days/weeks and change it again. Not sure how many miles you have, but I changed mine in my 2018 at 30k miles and was surprised how dirty the fluid already was. Were you topping it off with Mopar fluid or something else when you were checking levels?

 

[popcenator]

If I were you, unless you plan to take it in to the dealer under warranty, you might consider sourcing some fluid and a new pan and change the fluid. Drive it a couple days/weeks and change it again. Not sure how many miles you have, but I changed mine in my 2018 at 30k miles and was surprised how dirty the fluid already was. Were you topping it off with Mopar fluid or something else when you were checking levels?

I always use the 8&9 speed Mopar fluid to be safe. The fluid looks pretty clean when it drains back out, but I also have over 50K miles on the transmission so I might change it out soon anyway since it's close.

 

[Wild one]

I always use the 8&9 speed Mopar fluid to be safe. The fluid looks pretty clean when it drains back out, but I also have over 50K miles on the transmission so I might change it out soon anyway since it's close.

As stated above try doing a full service on the transmission with a new pan and filter,and go from there.
When you pull the battery posts,are you taking it out for a drive right after,and driving it like you stole it.
The 8 speed learns your driving habits,and i'm wondering if that just might be some of your issues, maybe you're babying it to much after the battery disconnect.
Do a battery disconnect when it's warm,then go drive it like it's a rental truck,lol