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Oil Leak


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#1 Zoso

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Posted 02 August 2009 - 07:54 AM

I have an oil leak. Not sure from where. I first noticed the leak when i saw the bottom of my oil pan damp with oil. It wasnt a lot so i thought maybe on my last oil change i spilled during filling and it ran down to the oil pan. So i cleaned it off a week or so ago and now its damp with oil again. Hard to tell where it is coming from.

I have used fully synthetic since the first oil chage...thought that could be the problem.

Any ideas?
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#2 Ryan00TJ

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Posted 02 August 2009 - 08:08 AM

From what I have gathered on a few sites it seems the GMT900's seem to have engine oil leak problems from the rear main seal and CPS crank position sensor. There is a sight plug on your bellhousing. Pull it out and look inside with a light and if its wet the leak is more than likely your rear main seal. Synthetic oil did not cause the leak, nor will it. Just faulty GM seals. With the 100K 5yr powertrain warranty take it to the dealer and let them worry about it.
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#3 Saurkraut

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Posted 02 August 2009 - 08:24 AM

From what I have gathered on a few sites it seems the GMT900's seem to have engine oil leak problems from the rear main seal and CPS crank position sensor. There is a sight plug on your bellhousing. Pull it out and look inside with a light and if its wet the leak is more than likely your rear main seal. Synthetic oil did not cause the leak, nor will it. Just faulty GM seals. With the 100K 5yr powertrain warranty take it to the dealer and let them worry about it.


+1 I had my rear main seal replaced at 26k...
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#4 bemr

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Posted 02 August 2009 - 08:29 AM

With the 100K 5yr powertrain warranty take it to the dealer and let them worry about it.


+1
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#5 Zoso

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Posted 02 August 2009 - 09:17 PM

sounds like a dealership trip. thanks for the info guys.
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#6 markintexas

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Posted 26 September 2009 - 11:38 AM

From what I have gathered on a few sites it seems the GMT900's seem to have engine oil leak problems from the rear main seal and CPS crank position sensor. There is a sight plug on your bellhousing. Pull it out and look inside with a light and if its wet the leak is more than likely your rear main seal. Synthetic oil did not cause the leak, nor will it. Just faulty GM seals. With the 100K 5yr powertrain warranty take it to the dealer and let them worry about it.


+1 I had my rear main seal replaced at 26k...


So I have a similar problem. My 07' Sierra had an oil leak at 20K and I took it into the dealer and after two days of diags the mechanic said the following was done, "Found oil and fluid at the rear of the engine, the rear engine cover is leaking and the tran's pump seal is leaking. Replaced the rear cover gasket and the rear main seal, also replaced the tran's pump seal and gasket and the torque convertor seal."

My question is why in 20K are all of these factory seals and gaskets breaking down, the truck hasn't been driven much and is in a typically clam climate, what can I expect at 40K? The mechanic also said that he had to drop the trans to get to the leaky spot, and I was told it was a 'minor' job. Dropping the trans seems to be a major issue to me. Have you had any additional trouble with your rear main or other seals around the center of the powertrain assembly? I'm beginning to believe that 100K is almost impossible for any new style of pickup due to the cost-effectiveness of the problems that start very early on in terms of engine and chassis life. Is there any hope?

Thanks,

Mark
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