1999 Chevrolet Silverado 1500 Logo
Anonymous Posted on Feb 24, 2013

Oil leak between oil pan and transmission.

I have a very slow oil leak between my transmission and oil pan. I almost wouldn't even so much call it a leak, more like moisture build up and a very slow drip. 3000 mile oil change and seems to have every drop that was put in it. Have been running synthetic for about 6000 miles now, changed once. The moisture covers the whole oil pan, filter, and front part of transmission. Any ideas?

  • Anonymous Feb 24, 2013

    It only as 1500 miles on its current oil change. I'm lucky that what hasn't blown off? I'll check the adapter O-ring.

  • Dan Jacobs
    Dan Jacobs Nov 12, 2013

    There are three sources of concern here #1 back by distributor is a oil pressure switch. Oil will run down the outside of transmission case. Usually can be detected it looked down on from top of engine at firewall. #2 Does this engine have a oil cooler then the adapter plate o-ring and gasket seep thay put oil on oil filter and at back of oil pan and inspection cover for flywheel. #3 rear main seal cover gasket this gasket covers the rear part of engine where the camshaft lifter oil feed is located leaks cold and seals up on a warm engine inspection cover has oil in it and starter is usually wet.

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  • Posted on Mar 20, 2013
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The crankshaft rotates in the engine block with main bearings. There may be a problem, and you can check the leak in Oil Filter.

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  • Posted on Feb 24, 2013
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Try running some of that high-mileage engine oil next time you do an oil change (it helps to swell engine seals slightly). If the problem clears up or is reduced, then it's likely that the rear main oil seal is starting to leak a little. The rubber seals will harden up and shrink a little with age.
I would also powerwash the entire area clean, so that way any leak will be easier to monitor and pinpoint.

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  • Posted on Mar 21, 2013
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Since your leak is very minor, try snugging all oil pan and valve cover fasteners. Do not overtighten.Wipe down oil pan, oil filter, and trans.cover and then inspect daily to find source of leak. It might be oil sending unit or slight leak at rear of a valve cover. If it turns out to be rear main seal, put some oil stop leak in the crankcase. It will swell the seals and should stop your leak. Hope this works for ya.

4 Related Answers

Anonymous

  • 94 Answers
  • Posted on Feb 02, 2009

SOURCE: 1993 chev. cavalier RS convt. has oil leak somewhere

one very common leak on 3.1 l is under throtle body where there used to be a distriburo.its located between transmission and tor rear of the engine .there is an o ring under it . check at the top under where the gas cable is.

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Anonymous

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  • Posted on Feb 10, 2009

SOURCE: leaking oil somewhere on oil pan on 1997 siverado 1500

If your truck is a four wheel drive check the oil filter adapter where the filter screws on, the o'ring can start to leaking.

Anonymous

  • 91 Answers
  • Posted on Mar 29, 2009

SOURCE: Excessive oil consumption

synthetic oil has smaller molecules which is why it is good for new cars - it gets into more places. it sounds like your car has been taken good car of but it still has some miles on it. what is happening is the synthetic is getting past the oil ring on your pistons (dont worry) and a small amount is getting burned off (not enough to fail emissions or notice in the exhaust) this happens just because of old age (being anything over 60000)i would try switching to a conventional oil at least for one oil change and that will solve your problem because the bigger molecules in the conventional oil will have a much harder time getting past the oil rings on the pistons.

Anonymous

  • 69 Answers
  • Posted on Dec 30, 2009

SOURCE: my 1994 camaro w/ 3.4L engine has an oil leak in

This is most likely a leak from your rear main seal. It happens and can be a pain to replace if you're a DYI kinda person without the nec. equipment.

  1. Raise and safely support the vehicle with jackstands.
  2. Remove the transmission.
  3. If equipped with a manual transmission, remove the clutch and pressure plate.
  4. Remove the flywheel assembly.
  5. Using a suitable prytool, carefully pry the old seal out.
6. Inspect the crankshaft for nicks or burrs, correct as required.
88143g59.gif Crankshaft rear main seal - 5.7L engine

To install:
  1. Clean the area and coat the seal with engine oil. Install the seal onto tool J-34686 for 3.4L engines, J 41349 for 3.8L engines or J 35621 for 5.7L engines.
  2. Install the tool (with the seal mounted to it) onto the rear of the crankshaft. Tighten the screws snugly to be sure the seal will be installed squarely over the crankshaft.
88143g60.gif Exploded view of the rear main seal installation - 3.4L engine
Click to Enlarge

  1. Tighten the wing nut on the installation tool until it bottoms out.
  2. Remove the tool from the crankshaft or rear oil seal housing, as applicable.
88143g61.gif Rear main seal and installation tool - 3.8L engine
Click to Enlarge
88143g62.gif After position the seal on the tool, install it to the crankshaft housing

  1. Install the flywheel.
  2. If equipped with a manual transmission, install the clutch and pressure plate.
  3. Install the transmission.
  4. Check the fluid levels, start the engine and check for leaks.

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you will need to add 2qts of transmission fluid then jack up the front of the car and look for the leak, if you do not see it then have someone start the car and look, you will be able to see it leak out, i thing it will end up being the pan, good day.
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bendarden.jpg

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