Jump to content

Coolant And Trans Fluid Mixing?

jsp00n

By jsp00n
in Ask A GM Technician

Recommended Posts

jsp00n Enthusiast

jsp00n

Posted
Posted

I got the oil changed in my wife's 02 Yukon Denali and noticed that the truck was leaking from the front passenger side wheel well. I took the truck back to the shop and they told me that somehow my transmission fluid and coolant were mixing and filling the overflow tank to the point that the overflow was pouring out a nasty milky mixture. Any ideas how this is happening and the best way to fix the problem?

bossier62guy Senior Enthusiast

bossier62guy

Posted
Posted
I got the oil changed in my wife's 02 Yukon Denali and noticed that the truck was leaking from the front passenger side wheel well. I took the truck back to the shop and they told me that somehow my transmission fluid and coolant were mixing and filling the overflow tank to the point that the overflow was pouring out a nasty milky mixture. Any ideas how this is happening and the best way to fix the problem?

 

The only place the two could meet is in the radiator....

Zembonez Senior Enthusiast

Zembonez

Posted
Posted
So, I should replace the radiator to fix this problem?

If you are sure it is trans fluid, then the cooler in the radiator has sprung a leak. Only way to fix that is replace the radiator... BUT... how can you be sure that the mixture isn't engine oil and coolant (this is the much more likely problem) I'd sure get it checked before you end up losing an engine or transmission due to contaminated lubrication. Not fun!

jsp00n Enthusiast

jsp00n

Posted
  • Author
Posted

well when they did the oil change, they topped off all my fluids and today the dipstick for the transmission was dry. I checked the oil and it seems fine. Thanks for the help.

bossier62guy Senior Enthusiast

bossier62guy

Posted
Posted
well when they did the oil change, they topped off all my fluids and today the dipstick for the transmission was dry. I checked the oil and it seems fine. Thanks for the help.

 

Once the radiator is replaced I'd flush the cooling system as well....

minibike132 Senior Enthusiast

minibike132

Posted
Posted

It sounds like a trans cooler leak. The distinction is easy to make, oil contaminated coolant will be greyish brown foam, trans contamination turns into a pink foam that looks a bit like a strawberry milkshake. Have the radiator replaced or atleast the internal cooler replaced, thats the only place contamination can take place. Have the cooling system THOROUGHLY flushed. The biggest problem with these leaks is not trans fluid in the coolant it's coolant in the trans. Even if your trans is empty usually at some point coolant will leak into the trans and then you have problems. The following is straight from the general on what to do if there is coolant contamination in the trans.

 

Important: If water or coolant is found in the transmission, the following steps must be performed:

 

Remove the transmission. Refer to the appropriate SI procedure.

Disassemble and inspect the transmission. Refer to Unit Repair Automatic Transmission - 4L60-E/4L65-E or 4L70-E.

Important: If water or coolant is found in the transmission, the following components MUST be replaced.

 

• Replace all of the rubber type seals.

 

• Replace all of the composition-faced clutch plate assemblies including the band.

 

• Replace all of the nylon parts.

 

• Replace the torque converter.

 

• Thoroughly clean and rebuild the transmission, using new gaskets and oil filter.

 

• Flush and flow check the transmission oil cooler using J 45096. Refer to Corporate Bulletin Number 02-07-30-052D or newer - Automatic Transmission Oil Cooler Flush and Flow Test Essential Tool J 45096 TransFlow .

 

I'm not the trans tech here so I have never gone this or the cheap route. I have seen some guys try the cheap route which is to replace the radiator and perform alot of flushes on both systems, replacing the trans filter every couple of flushes. That is a crap shoot at best (or so I hear) and is never a guarantee that the coolant in the trans will not cause problems down the line. I have seen the internals of one of these transmissions after multiple flushes and there was alot more coolant left over in the trans than you think, you can't ever get it out of the torque converter and coolant will swell the seals and clutches in a short amout of time.

 

Good luck to you, either way you go it is very labor intensive if any coolant did make it's way into your trans.

KCXLT Enthusiast

KCXLT

Posted
Posted

What about bypassing the rad completely and adding a bigger aux cooler for the transmission, probably cheaper than a new rad.

mndadof3 Enthusiast

mndadof3

Posted
Posted

Just adding a bigger cooler will not fix the hole in the internal trans cooler in the radiator, possibly causing coolant to get into the transmission, requiring the costly overhaul mentioned above

C & A s Dad Senior Enthusiast

C & A s Dad

Posted
Posted
Just adding a bigger cooler will not fix the hole in the internal trans cooler in the radiator, possibly causing coolant to get into the transmission, requiring the costly overhaul mentioned above

 

 

If he bypasses the internal trans cooler located inside the radiator and blocks off the inlet and outlet, the coolant cannot get into the trans or anywhere else because the lines will be disconnected.

 

This could certainly be done and save him from replacing the radiator. However, he will need a large (11 x 11 x 3/4) stacked plate cooler at minimum to keep the fluid temps down. This would double the size of the OE external cooler.

 

I would suggest he try this, flush the cooling system at least twice with a HD flush and not one of the 10 min quick flushes. Be sure to run the heater both front and rear on high during the entire flush as you will have trans fluid in both heater cores.

 

He has already received some good info on the trans. I believe I would have to try to flush it out if at all possible and see what happens in the coming weeks

 

Good luck to you and we would love to know what you end up doing.

  • 1 year later...
relco86 Enthusiast

relco86

Posted
Posted

I got a similar problem> I took my 07 sierra to a dealer to check on a stabiltrac problem. Here is the diagnosis I got from them> keep in mind i have 70k miles

 

no transmission fluid on dipstick

transmission fluid all in radiator

suggest replace radiator and hoses.

 

The quote I got was off the charts $1900. But I wanted it covered in warranty because the transmission failed (it had no fluid). The dealership said they had to replace the radiator first before they could determine a problem with the transmission. I took the truck to a local "reputable" mechanic and replaced the radiator and hoses $700. But I still have the problems shifting gears. So I have to take it back to the dealer to determine what I already knew in the first place (the trans is shot).

 

Heres my question> Can the "transmission problem" cause problems with the radiator. I.E> could the problem with my transmission now lead to a new problem with my new radiator???

Archived

This topic is now archived and is closed to further replies.

Go to topic listing

  • Recently Browsing   0 members

    • No registered users viewing this page.

  • Forum Statistics

    250.4k
    Total Topics
    2.7m
    Total Posts

  • Member Statistics

    342,840
    Total Members
    8,960
    Most Online
    appletrav
    Newest Member
    appletrav
    Joined

  • Who's Online   1 Member, 0 Anonymous, 269 Guests (See full list)

  • Latest Articles

  • Posts

    • newdude
      2 speed transfer case optional now?

      By newdude · Posted

      This is a 1/2 ton thing ONLY.  All HDs 2020-2026 have the two speed transfer case, with Autotrac as an option.     1/2 tons 2019-2026, regular 4x4s come with a single speed case (no 4LO!), and trucks with Z71 ordered, or all Trail Boss trucks come with the 2 speed case.  2 speed case is also an option on WT, and is also standard on High Country.  
    • newdude
      Different requirements for oil filters?

      By newdude · Posted

      2013 5.3 still to this day calls for the PF48 filter.  Which as a 15psi bypass pressure.     There is a TSB, 17-NA-157 that talks about the PF-63 and PF-64 filters which have a higher bypass rating of 22psi.    TSB HERE - temp.xml   "Beginning in 2012, the oil pumps began to regulate main gallery feedback instead of pump out pressure. This means that the oil pump now does not begin to regulate until pressure is built up to the main gallery. This change reduces the amount of time it takes to provide oil to the engine bearing and lifters during extreme cold start conditions.  Main gallery feedback oil pump control systems are present on the following engine families which use Spin-on oil filters: Small Gas Engine (SGE), Large Gas Engine (LGE), High Feature (HFV6) Gen2 and Small Block Gen5 gasoline engines. These engines with the main gallery feedback oil pump control systems are factory built with an ACDelco® oil filters"   It also calls out what engines use those filters.  The gen 4 small blocks were not on that list (LMG, LC9, L9H, L92, L94, L20, L96).  Gen 5 small blocks use the higher pressure filter.          That all said...   Your 7045 Napa filter is the PF63 equivalent, with 22psi bypass.  You are already using the higher bypass pressure filter.  You CAN keep using it, you don't technically have to use it though.  
    • Grumpy Bear
      Different requirements for oil filters?

      By Grumpy Bear · Posted

      Do you know WHY the filter relief setting was increased to 22 psig?    When the new system goes into the second stage the pump volume ramps up considerably. It was found that the 15 psi filter bypass setting put the filter in bypass on a warm engine when the second stage was activated. Raising the filter bypass setting forced the filter to do what it designed to do. Filter. Preventing debris from circulating during high load, high rpm operation.    So next question is how did GM find this out? VLOM/lifter failures and a deep dive by Melling Corp.    Last question. Is it required? Look at it like this; a motor may be equipped with a rev limiter. But it only works if the set point in reached. That 22 psig setting only matters if the pressure differential across the filter media exceeds 15 psig during normal warm operation. Second stage kicks in around 3000-3500 rpm.    I can't answer your question because I don't know you and how you use the truck. But I think there is enough information here to let you decide for yourself. 😉
    • Coastie05
      give me some tips to make my truck look better

      By Coastie05 · Posted

      Go back to OEM wheels. 
    • newdude
      2020 Trailboss 6.2 replacement

      By newdude · Posted

      Probably not their first rodeo, so it should go as planned most likely.  Typically the service manager or tech doing the swap will put some seat time to shake it down after they get it all put back together.  We usually put 50-100mi before we hand them back so if something happens, its not after you get it.  A coolant leaks, oil leaks, a ground left off or loose, vibration, etc.     The new engines so far have been good?  There's been a couple that have popped out there again (the replacement engine) but most have been okay.  

  • GM-Trucks.com Clubs

  • Popular Contributors

×
×
  • Create New...