Anyone service an Automatic Tranny with no dip...

[JOD]

Originally Posted By: demarpaint

What I fail to understand is if a car sits for lets say overnight on level ground. Isn't the cold level always going to be the same if the vehicle sits overnight on level ground? Calibrating a cold level check, and a hot level check, the way I mentioned should work, as long as the unit was properly filled from the beginning?


If the ambient temperature is the same, then sure. That's a big "if", though.

My transmission is also one which is finicky w/fluid level and the fluid expands more than conventional ATF (or seems to). I just measure the fluid cold and put back the same amount, making sure the fluid going in is measured at the ambient temp as well.

 

[demarpaint]

How would ambient temp have an effect on a cold fluid level after a 24 hour sitting period with no use? That is what I'm not understanding.

That would be like the oil level in your car rising if it sat for 24 hours in the summer vs the winter. 5 qts of oil is 5 qts of oil sitting in the pan. In the case of the transmission maybe it is 10 qts of ATF, summer or winter the level should be the same? Once all the fluid is back in the pan after sitting for 24 hours (not started or driven) I don't see the effect of temperature.

I'm not challenging you BTW I'm trying to understand. I know checking the level after a car has been driven is a PITA, and I've had many mechanics screw it up doing transmission services over the years. Mostly overfilling the unit.

 

[brianl703]

It would have an effect, whether it is enough to worry about is another question. I don't happen to believe that it is enough to worry about.

 

[JOD]

Originally Posted By: demarpaint
How would ambient temp have an effect on a cold fluid level after a 24 hour sitting period with no use? That is what I'm not understanding.



Where I live?? Not much. It's between 45-80 degrees year-round.

I think the reason the mfg (in my case) specifies the fluid-setting temp @ 40C is because some people may be checking it at 10F, and others @ 100F.

From a practical standpoint, 100F degrees move the fluid on my dipstick about 12mm, and the progression seems fairly linear. So if you live somewhere with varying ambient temps, that could make a difference.

 

[demarpaint]

I get what you're saying, here's my thinking about letting the car sit for 24 hours. If you were to take a qt of ATF and let it sit at lets say 20*F, for 24 hours and check it out, the level won't change. If you took that same qt and let it sit at any ambient temp you like, the level isn't going to change. So I'd think the most accurate reading would be stone cold after a 24 hour sit assuming the stick was calibrated for that. In your case temps aren't an issue, I would think that from about 32*-100*F it wouldn't matter much either. In fact probably even colder.

I honestly believe the reason checking the level is more difficult is because a shop doesn't have the luxury to wait for a car to sit 12-24 hours before checking the ATF level. Or a person who discovers a leak, while stopping to gas up on a long trip can't wait either. I have the luxury of being able to let a car sit for a week if I had to. We have 3 cars and two drivers here.

 

[brianl703]

Specifying a hot level would result in a slight overfill if the level were checked cold.

A slight overfill is probably better than a slight underfill.

 

[SteveSRT8]

Fine for many, near death for others.

Too many different trans designs for that generalization.

Demarpaint: While your reasoning seems sound I prefer to follow the book. There is always a reason for the procedures specified, but I can't find any flaw in your reasoning.

 

[brianl703]

In those transmissions that have dipsticks, I have never found the level to be critical. There's "too much" and "not enough" and the difference between them on the order of 1/2 quart or more.

 

[demarpaint]

Originally Posted By: SteveSRT8

Demarpaint: While your reasoning seems sound I prefer to follow the book. There is always a reason for the procedures specified, but I can't find any flaw in your reasoning.


I hear ya. I can't find a flaw in it either, but was hoping if someone could they would explain explain why. I really think it has everything to do with being practical, and not being able to wait for all the fluid to be in the pan and take a reading 24 hours after shut down.

If the cold level is 100% on the money then the hot level will be 100% on the money, and vice versa. One of them can't be wrong, and the other be spot on. If so them I'm totally off base and am eager to learn why.

 

[caravanmike]

Originally Posted By: demarpaint
Originally Posted By: SteveSRT8

Demarpaint: While your reasoning seems sound I prefer to follow the book. There is always a reason for the procedures specified, but I can't find any flaw in your reasoning.


I hear ya. I can't find a flaw in it either, but was hoping if someone could they would explain explain why. I really think it has everything to do with being practical, and not being able to wait for all the fluid to be in the pan and take a reading 24 hours after shut down.

If the cold level is 100% on the money then the hot level will be 100% on the money, and vice versa. One of them can't be wrong, and the other be spot on. If so them I'm totally off base and am eager to learn why.

i don't see anything wrong with your reasoning. mike

 

[CBR.worm]

It might just be that they know it runs at about xxx degrees when hot. The mfg doesn't know if cold for you is 1 degree or 100. If you make a cold mark on Monday, it should still be the same on Wednesday. But if you made your cold mark in Florida and checked it in Alaska it might be off a bit. Even still, you wouldn't think it would be a huge difference.

 

[Petersubaru]

Originally Posted By: demarpaint
Originally Posted By: cbear
I've been looking at this because I have a Dodge Nitro with the sealed NAG1 aka W5A580 transmission. This is the one you're suppose to use a graduated dipstick with a sacn tool that reads the trans temp. From what I've read, none of the Chrysler NAG1s came with a dipstick, just the sealed tube.

I'm going to do a drain and fill, so I just got an old Ram truck dipstick and scribed the cold line. Once I get a good hot reading, I'm going to go from there. Also going to add a spin on remote filter and a drain plug kit.

From what I've read, the MB and Sprinter van NAG1s already have a drain plug as well as torque converter drain access. I do not think that is the case with the Chryslers.


My Jeep calls for the same scan tool as your Nitro. I got a dipstick from an 06 Liberty which used the exact same transmission as the one in my 08.

What confuses me is this. If the vehicle sits overnight, shouldn't that cold level always be the same? I understand the operating hot running level can be different depending on how hot the ATF is, but the cold level should always be the same. I'd be willing to let the vehicle sit on level ground for 24 hours to check cold level. Drive and let it sit another 24 hours, if the level remains constant after the 24 hour sit, I'd work off that level.

I can understand how a hot fluid level is important to a shop, they don't have the luxury of allowing a vehicle to sit 24 hours so all the fluid could return to the pan and then check the level.

I'd be interested in knowing how this works out for you, report back if you can!

Thanks
...I have been checking the transmission oil "cold" for many yrs now..first I got the dealer to verify that the transmission has been filled to the max...then established a reference point on the vehicle to determine when it is level..

 

[demarpaint]

Originally Posted By: CBR.worm
It might just be that they know it runs at about xxx degrees when hot. The mfg doesn't know if cold for you is 1 degree or 100. If you make a cold mark on Monday, it should still be the same on Wednesday. But if you made your cold mark in Florida and checked it in Alaska it might be off a bit. Even still, you wouldn't think it would be a huge difference.


I'm going to take a mason jar and draw a line with a marker on the jar fill to the line with ATF, and sit it in the freezer overnight. Then sit it in the 70*F house. I'm guessing the level will be exactly the same, if not all bets are off. If that's the case the cold level check should work. Then the next step would be to determine if the factory filled it correctly, if so I'm pretty confident my method will work.



Originally Posted By: Petersubaru
[I have been checking the transmission oil "cold" for many yrs now..first I got the dealer to verify that the transmission has been filled to the max...then established a reference point on the vehicle to determine when it is level..


It's working for you! Good to know!

 

[crinkles]

my U241E transmission consistently needs 3.7 L for a drain and fill instead of 3.5 L per the handbook.

my thinking as to the reason why ATF is checked after moving through the gears is that that process controls the level of the fluid most reliably.

person A may end his day by backing his truck into his car park then putting it in park. Person B may end it in D, parking it in "P", Person C may stop in "L" afer climbing the mountain track to his house and leave it in neutral without moving it through R to park.

So if the volume of hydraulic fluid in the final circuits each person uses is different, and drain out different amounts to the pa or holds more, the a cold morning check with the car off won't be comparable.

FWIW I can only get a cold reading on my dipstick; and the point where the fluid sits for me in a cold check before turnign the engine over is between the upright legs of the "H" of "HOT" on the dipstick. when i trun it over and go through the gears, the ATF gets sucked up to the circuits and the level on the stick drops to the correct two "COLD" dots.

 

[demarpaint]

Thanks crinkles, good info. I'm curious if your level is at the same point of the stick cold every morning? I was going to experiment to see for myself with my Aerostar. Some days I back into the driveway, some I pull in, I can check both ways.

The problem I found checking hot is there is always ATF slung up a ways in the fill tube and getting a reading takes a few tries. At any rate it should be interesting.

 

[Petersubaru]

Originally Posted By: demarpaint
Originally Posted By: CBR.worm
It might just be that they know it runs at about xxx degrees when hot. The mfg doesn't know if cold for you is 1 degree or 100. If you make a cold mark on Monday, it should still be the same on Wednesday. But if you made your cold mark in Florida and checked it in Alaska it might be off a bit. Even still, you wouldn't think it would be a huge difference.


I'm going to take a mason jar and draw a line with a marker on the jar fill to the line with ATF, and sit it in the freezer overnight. Then sit it in the 70*F house. I'm guessing the level will be exactly the same, if not all bets are off. If that's the case the cold level check should work. Then the next step would be to determine if the factory filled it correctly, if so I'm pretty confident my method will work.



Originally Posted By: Petersubaru
[I have been checking the transmission oil "cold" for many yrs now..first I got the dealer to verify that the transmission has been filled to the max...then established a reference point on the vehicle to determine when it is level..


It's working for you! Good to know!
..I doubt if the mason jar trick will work since it is not metal and the quantity would be to small to test... when my car sits outside for ex. overnight, most of the expansion or contraction is related to the body or case of the transmission..I have no way of providing an example concerning ATF...however, when looking at my coolant level on both vehicles, there is definitely a change to that level depending on how hot or cold it is outside like first thing in the morning...also the biggest noticeable change comes when it gets cold..which might mean that I can add 4 or 5 tablespoons of coolant to the system..in other words it makes no difference..I would tend to think the same for the atf...also when checking the transmission fluid cold, I can see no difference when looking at my newly scribed line, be it hot or cold outside...

 

[Petersubaru]

Originally Posted By: demarpaint
Thanks crinkles, good info. I'm curious if your level is at the same point of the stick cold every morning? I was going to experiment to see for myself with my Aerostar. Some days I back into the driveway, some I pull in, I can check both ways.

The problem I found checking hot is there is always ATF slung up a ways in the fill tube and getting a reading takes a few tries. At any rate it should be interesting.
...then you have to ask yourself, "how hot is hot",..I can drive around town all day long and the transmission fluild will never heat up as when I have just returned from a 1 hr trip on the highway..(right after my highway drive is when I took my car to the dealer for them to use the temp probe)..all set up in advance..

 

[demarpaint]

Dealers around here set up an appointment in advance and then the car sits till they are ready to do it.

How much do they charge to check the fluid?

Another thought is this. I can drive half an hour take a temp reading of the transmission pan at a set location. Use that temp to make a mark on the stick. Check the fluid when the pan reaches that temp. Check the same way each time.

This isn't rocket science, although the dealers would like us to think that way. LOL I would check several times both hot and cold to be certain, and have two marks. The way my dealer works I'm more confident in my method.

I understand the transmission can expand and contract but I don't think all that much to have a major effect on levels, maybe a few ounces?

 

[JOD]

Originally Posted By: demarpaint


I'm going to take a mason jar and draw a line with a marker on the jar fill to the line with ATF, and sit it in the freezer overnight. Then sit it in the 70*F house. I'm guessing the level will be exactly the same, if not all bets are off.


I'm betting that it won't be the same, but there's one way to find out!

Something to keep in mind though is that the rate of expansion is likely to be similar to viscosity, in that it will be non-linear, i.e. the fluid will expand more per degree as it gets warmer.

What is the recommended temperature to check this fluid, anyway?

 

[demarpaint]

I'm positive the hot and cold levels will be different. What I want to see is if the cold level is always the same or not. The stick the techs use is calibrated based on temps, so basically they can check the level at any temperature. That is how it was explained to me. I'll see over the period of a few days how hot the pan gets after half an hour on the parkway. I have plenty of time.

I'm still looking into this and getting ideas. Hopefully after 30 minutes on the highway the pan temp is pretty consistant, if not I'll have to establish a temp and base my calibrations on that.