1. Welcome to Tundras.com!

    You are currently viewing as a guest! To get full-access, you need to register for a FREE account.

    As a registered member, you’ll be able to:
    • Participate in all Tundra discussion topics
    • Transfer over your build thread from a different forum to this one
    • Communicate privately with other Tundra owners from around the world
    • Post your own photos in our Members Gallery
    • Access all special features of the site

Head scratcher oil leak

Discussion in '1st Gen Tundras (2000-2006)' started by tundrasteve47, Mar 24, 2024.

  1. Mar 24, 2024 at 12:19 PM

    tundrasteve47 [OP] New Member

    Mar 16, 2024
    I have a 2006 dc SR5 4wd, 205k miles. Just bought the truck 2 weeks ago and have been doing some repairs (brakes, rack and pinion, transfer case actuator, valve cover gaskets, spark plugs, MAF sensor, LBJ, etc.)

    Im no mechanic and have just been learning off of YouTube but everything has been going smoothly.

    No leaks were present before I started doing repairs on the truck, which I believe the oil levels were so low there was nothing to leak.

    I'm being stumped by an oil leak after I changed out the front diff fluid.

    Truck had not been taken care of and all oils/fluids were pretty black. So after valve covers were fixed I went ahead and changed the engine oil finally. 5 1/2 L came out pretty black. Put in the right amount and kept doing repairs.

    Then I changed out front/rear differential fluid and transfer case fluid all to the service Manual specs. Went on a drive and came back to realize that there is oil coming from under the truck near the flywheel housing under cover area and/or the front diff rear seal where the front driveshaft meets the front diff.

    My initial thought was to change out the breather hoses which were corroded shut and that way the diff fluid pressure doesn't build up and exit out the seals. Did that and still have the leak. I have also changed out the breather valves behind the engine and firewall.

    The flywheel housing under cover has a little gap underneath it to which I then thought, oh man that can't be right, so I stuck a little straw under the gap and saw there was oil on the straw, so maybe that's where the leak is coming from. I don't know if the flywheel is suppose to be covered in oil or not or if I have a rear main seal leak.

    Again it was not leaking once I changed the engine oil and took it for a drive, before I even touched the front diff, only after.

    Im hoping someone can give me further clarity.

  2. Mar 24, 2024 at 2:11 PM

    shifty` Kaboom, the Jedi’s back to seismic!

    Jun 20, 2020
    '06 AC Limited V8/4WD
    (see signature for truck info)
    You were working on the top-end with the valve cover gaskets. Did you check the back of the block to see if maybe you have some oil coming off the back of the heads at the half moon plugs? I'm trying to visualize in my head if it could end up down that way, but I'd be looking high up on the back of the block to see if you can see something, and if it truly just started, that's the first place I'd go to look. Especially if following YouTube, there are a couple of valve cover change videos that absolutely show you the wrong way to do stuff on that topic!

    Do yourself a favor, hit this thread: https://www.tundras.com/threads/so-you-wanna-buy-just-bought-a-1st-gen-tundra-eh.115928/

    Look about 4-5 paragraphs down. See all those links in a row? Click on the Service Manual link. Download the one for your year range. Use that as your reference. Seriously.
  3. Mar 24, 2024 at 3:35 PM

    w666 D. None of the above

    Dec 17, 2019
    04 Access Cab SR5 V8 4WD
    None yet
    What kind of engine oil did you use...dino or synthetic? If you used synthetic, it's possible that this may be the first time (unless you know differently). Synthetic oil has a smaller molecular structure (or so I'm told) and it tends to find leaks where regular oil didn't. In such case you may consider @shifty` approved AT-205
    Last edited: Mar 25, 2024
    tundrasteve47[OP] likes this.
  4. Mar 26, 2024 at 12:44 PM

    tundrasteve47 [OP] New Member

    Mar 16, 2024
    Well I Narrowed it down to the front differential rear seal where it meets the front driveshaft. Took it to a mechanic to get a new seal, now I'm being told that the pinion is moving around in there after they removed the driveshaft and it is not supposed to be. They are saying I need a new front diff all together which isn't hard to fathom because when I was changing out the diff fluid it was black sludge. Does anyone know if the front differential is floating or not? thank you

Products Discussed in

To Top