Automatic Transmisson Fluid Check

[Tank2112]

So what's the deal with the cooler valve needing to be hotter than specified transmission temp test range, in order to open valve and flow fluid through cooler? Couldn't you heat cooler valve itself with say a small torch to reach 160 degrees (or what ever temp opens valve so fluid will pass through cooler), while still maintaining required transmission temp range?

And do you really think if you take your Jeep to a dealer, the service tech will make sure all steps are followed? Maybe the torque converter, but also make sure fluid flows through the transmission cooler?

 

[Robr651]

So what's the deal with the cooler valve needing to be hotter than specified transmission temp test range, in order to open valve and flow fluid through cooler? Couldn't you heat cooler valve itself with say a small torch to reach 160 degrees (or what ever temp opens valve so fluid will pass through cooler), while still maintaining required transmission temp range?

I actually don’t think the bypass opens until around 150-160 so the check / fill process doesn’t actually have anything to do with the bypass. It definitely doesn’t open at 86.

And I don’t think any dealer will care that you followed the check / fill steps unless something breaks and they can blame you. I just followed them because it worked.

 

[Tank2112]

I actually don’t think the bypass opens until around 150-160 so the check / fill process doesn’t actually have anything to do with the bypass. It definitely doesn’t open at 86.

And I don’t think any dealer will care that you followed the check / fill steps unless something breaks and they can blame you. I just followed them because it worked.

I guess the question is, do you need the cooler valve to open and allow fluid to flow through the cooler in order to properly set transmission fluid level? Hence, the question about heating cooler valve so it will flow fluid through cooler while still maintaining required transmission temp range of 86-120 degrees. If not how would you know if cooler or lines have any air that could result in fluid level being low?

 

[stumblinhorse]

I guess the question is, do you need the cooler valve to open and allow fluid to flow through the cooler in order to properly set transmission fluid level? Hence, the question about heating cooler valve so it will flow fluid through cooler while still maintaining required transmission temp range of 86-120 degrees. If not how would you know if cooler or lines have any air that could result in fluid level being low?

This is a great question. But really only relevant if you were to completely drain the lifeguard fluid. Which you can’t. The procedure to service a zf8 assumes that only a portion of the fluid is being replaced. Not all. If you want to fully replace all the fluid you would need to perform the service multiple times with a short period between. Kinda like what carbon steel is doing from the link I posted. So the procedure to service or top off assumes the cooler lines are full since they are closed. They will not open during the refill/top off procedure. That it why driving it around a bit and topping it off is required as that will ensure the cooler lines are opened and then purged of air.

 

[Mouse]

You know what would solve all the disagreements And confusion.

 

[stumblinhorse]

You know what would solve all the disagreements And confusion.
View attachment 24562

I googled dipstick and somehow a picture of me showed up!

 

[stumblinhorse]

On a serious note, No dipstick is because they don’t want people messing with it. And they want it “sealed”. A few intelligent folks on a forum can’t decide the right way to top it off. Imagine the complete cluster it would be for the masses for how/when to check the level. My 68rfe trans gets fill thru the dipstick what pain it is putting almost 3 gallons of atf thru the tiny dipstick tube.

 

[Robr651]

On a serious note, No dipstick is because they don’t want people messing with it. And they want it “sealed”. A few intelligent folks on a forum can’t decide the right way to top it off. Imagine the complete cluster it would be for the masses for how/when to check the level. My 68rfe trans gets fill thru the dipstick what pain it is putting almost 3 gallons of atf thru the tiny dipstick tube.

Very true