Mystery of transmission fluid

[SledDog]

I'm thinking breather. When you are adding oil, do you always top it off to the full mark? If so, you could be losing it via the breather. I had that issue on my Road King. I kept seeing oil on the ground, and the trans level was lower then the last time I checked it. After checking everything I could think of, except the breather hose, I finally took a look at it. It was the only place I could be losing it from. Sure enough, after a long ride the end of the breather hose was wet.

Turns out I was actually over filling it. I drained the trans, and refilled with correct amount. I made a witness mark on the stick to indicate the "correct" full level. No issues or problems after that.

 

[joel]

Go get some engine / transmission oil dye from NAPA #765-2661 around $10.00, ADD 1/4 -1/2 of the bottle into the transmission take for the 100 mile ride, than, while in the garage, semi dark area, pull the dip stick out and use a black light on it, kit # 765-6010 about $30.00, to see what the oil looks like with the light and glasses, than look around the transmission and vent area, and just for fun of it pull a few drops from the engine oil and see if there is dye in it.
We use this method all the time to locate location of oil leaks, if you have more dye than needed as per volume you can see the dye as brown without the glasses and light. No need to flush it out either.

 

[Dark Horse]

I'm thinking breather. When you are adding oil, do you always top it off to the full mark? If so, you could be losing it via the breather. I had that issue on my Road King. I kept seeing oil on the ground, and the trans level was lower then the last time I checked it. After checking everything I could think of, except the breather hose, I finally took a look at it. It was the only place I could be losing it from. Sure enough, after a long ride the end of the breather hose was wet.

Turns out I was actually over filling it. I drained the trans, and refilled with correct amount. I made a witness mark on the stick to indicate the "correct" full level. No issues or problems after that.

If my transmission fluid level was dropping to a certain point on the dip stick , then stabilising , I would tend to think that I was indeed over filling it , but the fact remains that eventually the level will drop so much that it doesn't even reach the end of the dip stick !

Who checks transmission fluid levels every 100 miles? One of my bikes has about 35k miles on it and I have never checked fluid level, even after a change. No way a tranny leaks that much without leaving some physical trace of the leak no matter what tranny fluid the OP uses. Tourbox identified all the locations where tranny fluid can leak out and if there is no physical trace of a leak at one or more of those locations, the tranny is not leaking; tranny fluid does not evaporate. The OP should stop checking every 100 miles and put 500 miles on the bike, check and report.

I agree with everything you say , but it would take a very brave man to ride his bike around knowing that there is not enough fluid in the transmission to even reach the dipstick !
I only started checking every hundred miles after I realised I had a problem

 

[dolt]

If my transmission fluid level was dropping to a certain point on the dip stick , then stabilising , I would tend to think that I was indeed over filling it , but the fact remains that eventually the level will drop so much that it doesn't even reach the end of the dip stick ! I agree with everything you say , but it would take a very brave man to ride his bike around knowing that there is not enough fluid in the transmission to even reach the dipstick ! I only started checking every hundred miles after I realised I had a problem

You make my point. How do you know the level will drop to the end of the dipstick? You won't know unless you stop measuring every 100 miles. You would be surprised how long the tranny will last on very low fluid levels; no need to be "brave", the tranny will not suffer.

All I am saying is that a loss of 3.5 ounces of tranny fluid leaking from the tranny is a serious leak and will leave a physical trace and dye is not necessary to see that. If there is no physical trace, then the fluid has to be migrating from the tranny to another location and there is only one location to where it can migrated and that would be the oil pan if there was a break in the gasket between the trans case and oil pan; very unlikely as well. Trans fluid could leak into the primary but that would mean the main shaft/5th gear seal and/or the MDG seal would have to be letting trans fluid out and that is unlikely to occur without leaving a physical trace.

I still think there is something wrong with your data collection. Set the dipstick level on full and ride more than 100 miles and see if the level stabilizes. As long as you can see some trans fluid on the stick, even if just barely, the tranny will not be damaged in the process.JMHO.

 

[Jeff Klarich]

As stated in other posts if you're losing that much fluid you have a big leak that would be detectable under your bike OR 1 of the other holes is filling up with tranny fluid.

A simple test is add some dye or drain tranny and fill with Red line heavy, go for a long ride, recheck tranny and check the other 2 holes for levels and any seepage.

If no seepage is detected then there is something wrong with your calculations.
BTW, how are you checking the tranny level? on the jiffy stand or standing straight up?

 

[Blue Wide Glide]

I had a primary leak a few years ago, and bought a dye and UV light dye detector kit at Amazon. I also switched to red line transmission fluid which as Jeff said, makes a leak look like the transmission is bleeding. I found they were both "weeping".

 

[Dark Horse]

You make my point. How do you know the level will drop to the end of the dipstick? You won't know unless you stop measuring every 100 miles. You would be surprised how long the tranny will last on very low fluid levels; no need to be "brave", the tranny will not suffer.

All I am saying is that a loss of 3.5 ounces of tranny fluid leaking from the tranny is a serious leak and will leave a physical trace and dye is not necessary to see that. If there is no physical trace, then the fluid has to be migrating from the tranny to another location and there is only one location to where it can migrated and that would be the oil pan if there was a break in the gasket between the trans case and oil pan; very unlikely as well. Trans fluid could leak into the primary but that would mean the main shaft/5th gear seal and/or the MDG seal would have to be letting trans fluid out and that is unlikely to occur without leaving a physical trace.

I still think there is something wrong with your data collection. Set the dipstick level on full and ride more than 100 miles and see if the level stabilizes. As long as you can see some trans fluid on the stick, even if just barely, the tranny will not be damaged in the process.JMHO.

I understand what you're saying , but the fact remains that the fluid level , unless I add to it , will always drop to the point where it doesn't register at all on the dip stick.
I know the transmission will still happily function with a lesser amount of fluid , but once it disappears, I have no way of knowing how much , if anything , is in there.
You seem very knowledgeable in this field , my friend !
I can't understand how the engine oil filler is in the gearbox casing and how the transmission fluid and engine oil drain plugs are BOTH in the oil pan !!

 

[Jeff Klarich]

I can't understand how the engine oil filler is in the gearbox casing and how the transmission fluid and engine oil drain plugs are BOTH in the oil pan !!

Different compartments within the pan.

 

[dolt]

I understand what you're saying , but the fact remains that the fluid level , unless I add to it , will always drop to the point where it doesn't register at all on the dip stick. I know the transmission will still happily function with a lesser amount of fluid , but once it disappears, I have no way of knowing how much , if anything , is in there.
You seem very knowledgeable in this field , my friend ! I can't understand how the engine oil filler is in the gearbox casing and how the transmission fluid and engine oil drain plugs are BOTH in the oil pan !!

You did not answer my question. How do you know the fluid level will drop to the point it won't register on the dipstick if you are refilling to full every 100 miles?

The engine oil filler is not connected to the trans case, it is connected to the oil pan.Take a look at the attached diagram. The trans fluid is contained in the trans case and the oil is contained in the oil pan; two separate containments. The trans fluid drains from the trans case via a passage cast into the oil pan (red rectangle).

 

[tourbox]

I am trying to attach a parts break down of your oil pan & tranny. If it works look at #15, that's the drain for your tranny. #8 is the gasket between oil pan & tranny housing. If you look at the inside of the pan at the gasket area, where #15 meets the pan, you will see a hole looking object. That is actually a pipe channel to drain the tranny fluid. I don't have photo shop so I couldn't make notes on the pic.
You can also go to Dodge City HD for a OEM parts look. That's where the pic came from
tourbox