Question about 1999 GMC Yukon

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99 yukon transmission coolant line parts diagram

I need a parts diagram for the tranny coolant lines running from the radiator to the transmission.

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6 Suggested Answers

  • 2 Answers

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Posted on Jan 02, 2017

  • 1 Answer

SOURCE: Transmission cooler line blew off

transmission line blew off lost all coolent & trans. fluid

Posted on Dec 31, 2008

  • 51 Answers

SOURCE: I have a leak of


Posted on Jan 17, 2009

  • 1779 Answers

SOURCE: Transmission coolant line leaking on the transmission side.

Is the line before and after the connector steel? If you can cut the leaking section out w/ a hack saw, u can slip a section of gas line over the trans cooling line, and put a clamp on both ends, quick cheap fix that will last a long time.

Posted on Mar 19, 2009

SOURCE: Transmission temp running 160 degrees in my 2007 Yukon Denali

I you did it by yourself is better to tell the dealer that you truck has that problem dont tell them that you did that because you may have voided the warranty.

Posted on Jul 18, 2009

  • 42 Answers

SOURCE: oil is in my engine coolant reservoir as well as my radiator

Most likely the intake manifold has a broken gasket or iteslf is broken.

take it to a shop and have them diagnose it by checking for HC's in your coolant. If there are non present, then it could be inside of the timing cover or the intake. If there are HC's present, you will need a new Head, Engine or just Head Gaskets, but if it's over 150,000 miles, you may want to just buy an engine if that's the case. You can't repair a high mileage engine with new top end components because it will "**** out" or ruin the bottom end shortly after installation.

Good luck! Hope that helps.

P.S. - I have mroe GM's come in with that same symptom than any other vehicle. After your repairs are complete, get rid of the DEXCOOL and go with a good, green antifreeze. It works much better than DEXCOOL.

Kevin, ASE Certified

Posted on Sep 12, 2009

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