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Transmission oil leak - what part is it leaking from ?

Eswaroop

By Eswaroop
in 6.6L Duramax Diesel (L5P)

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Eswaroop Enthusiast

Eswaroop

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Hi I have a 2024 GMC sierra 2500 HD with 5k miles on it - was under the truck to look for something and noticed that there’s red fluid leaking from this component - not sure what it is but looks like some sort of transmission sensor or valve ? 

IMG_0696.jpeg

newdude Senior Enthusiast

newdude

Posted
Posted
18 minutes ago, Eswaroop said:

Hi I have a 2024 GMC sierra 2500 HD with 5k miles on it - was under the truck to look for something and noticed that there’s red fluid leaking from this component - not sure what it is but looks like some sort of transmission sensor or valve ? 

IMG_0696.jpeg

 

 

6.6 gas or 6.6 diesel?

newdude Senior Enthusiast

newdude

Posted
Posted
22 minutes ago, Eswaroop said:

Hi I have a 2024 GMC sierra 2500 HD with 5k miles on it - was under the truck to look for something and noticed that there’s red fluid leaking from this component - not sure what it is but looks like some sort of transmission sensor or valve ? 

IMG_0696.jpeg

 

 

 

Nevermind.  6.6 Duramax.  That's the fuel cooler.  You are seeing either diesel fuel or engine coolant (or a combo of both) leaking.  

Eswaroop Enthusiast

Eswaroop

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Posted

Duramax - correct - Ugh that’s not good is it - mixing coolant with fuel.. it’s gummy so I’m guessing both are leaking but I don’t smell any diesel so it might be just the coolant.  I have to say though - the fluid I see looks too thick to be coolant - almost a transmission oil consistency  

Eswaroop Enthusiast

Eswaroop

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Posted (edited)

Ok on further inspection looks like the transmission fluid is leaking from the axle next to the fuel cooler and getting sprayed on to the cooler   - is that a possibility ? There’s a slight bit of oil on the shaft 

IMG_0700.jpeg

Edited by Eswaroop
newdude Senior Enthusiast

newdude

Posted
Posted
On 7/8/2024 at 5:15 PM, Eswaroop said:

Ok on further inspection looks like the transmission fluid is leaking from the axle next to the fuel cooler and getting sprayed on to the cooler   - is that a possibility ? There’s a slight bit of oil on the shaft 

IMG_0700.jpeg

 

 

The piece the arrow is coming from, that's the transfer case.  Looks like the output side going to the front drive shaft.  Transmission would be in front of the transfer case.  

Eswaroop Enthusiast

Eswaroop

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Posted
On 7/10/2024 at 2:40 PM, newdude said:

Hmm ok so the output side shaft going to the front is leaking at the transfer case.. is that the same fluid as the transmission ? Are they connected or will I run out of fluid fairly soon with that leak ( if transfer case is isolated ) 

 

The piece the arrow is coming from, that's the transfer case.  Looks like the output side going to the front drive shaft.  Transmission would be in front of the transfer case.  

 

newdude Senior Enthusiast

newdude

Posted
Posted
On 7/11/2024 at 4:18 PM, Eswaroop said:

 

 

 

There are two seals, one on the tcase input from the transmission, and one on the transmission side where they bolt up together.  Transmission takes Dexron ULV, transfer case takes Dexron 6, so two different fluids.

 

Either way it sounds like a trip to the dealer for some UV tracer dye added to the transfer case and have it leak tested.  If the t-case has no dye anywhere outside it, then they should add some to the transmission.  Warranty time.

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