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How to change gear oil in '78 308?

Discussion in 'Technical Q&A' started by Lee-'78_308, Nov 27, 2003.

  1. Lee-'78_308

    Lee-'78_308 Formula Junior

    Jan 14, 2003
    275
    Maryville, TN
    Full Name:
    Gary Lee Pierce
    Some specific questions that were not answered by the archives:

    1. Where is the fill point in the top of the engine?

    2. What is the G**D***** measurement of the differential side hex plug??!! 8mm is too small; 10mm is too big; I searched and finally found a 9mm at Sears and it's too big!!! Do they even MAKE an 8.5mm?

    Any other tips/advice?

    BTW, I am filling with Redline 75W90NS, which a performance place in Knoxville ordered for me. This seemed to be the majority choice in the archives. I am adding some Kendall limited-slip additive also.

    Thanks to all!
     
  2. Steve Magnusson

    Steve Magnusson F1 World Champ
    Lifetime Rossa

    Jan 11, 2001
    18,167
    Texas
    Full Name:
    Steve Magnusson
    Lee -- Refer to the OM for your model/year/version. The (multiple) drain and fill plugs are well documented (and there's usually a small illustration in the "Lubricants" section that's useful for seeing how the transfer gear reservoir holds a small volume above the main reservoir). No excuses;) -- you can get the OM from the Owner's site.

    My F have been a mix of various 10 mm and 12 mm female hex drive plugs, but nothing smaller -- perhaps yours has been "repaired"? Try the inch sizes too -- just a thought...
     
  3. Doc

    Doc Formula Junior

    Sep 13, 2001
    886
    Latham, New York
    Full Name:
    Bill Van Dyne
    Lee--I believe that the drain plug for the gearbox is supposed to be 10mm, with the oil pan one being 12mm. Those are the sizes on my '85 308. If the metric sizes don't fit then perhaps someone retrofitted with sae plugs. Good luck--and Happy Thanksgiving!
     
  4. Doc

    Doc Formula Junior

    Sep 13, 2001
    886
    Latham, New York
    Full Name:
    Bill Van Dyne
    Lee--forgot to respond to the other Q. The proper way to fill the gear box is through the gearcase cover plug ( it's another 10 or 12 mm allen head). It's located at the top and fwd on the gearcase cover--right near your oil cooler and coils. Remove the rear plug from the gearbox itself and fill through the top gearcase cover plug until the oil runs out of the rear plug.Once that happens the gear case and transaxle are properly filled. Be sure to keep the car level doing this procedure
     
  5. Lee-'78_308

    Lee-'78_308 Formula Junior

    Jan 14, 2003
    275
    Maryville, TN
    Full Name:
    Gary Lee Pierce
    UPDATE: OK, I found the REAL rear fill plug, and it's a regular 12mm. (I was looking at some nipple-looking thing on the side).

    Now for the next problem: I can't get it out. I have twisted a 12mm hex key to pieces trying to get it out, and I don't have a 12mm hex nut. The only one I can find on the internet or locally is in a set of SK metric hex nuts for $59. Do I really have to shell out $59 to get a single needed hex nut? Sears tops out at 10mm on single ones, as does Wal-Mart. Haven't checked Home Depot or Lowe's.


    This leads to my next question. Do I really HAVE to get it out? Can I just fill with 4.05 liters of gear oil, as in the OM and figure it's enough?
     
  6. f355spider

    f355spider F1 World Champ
    Rossa Subscribed Owner

    May 29, 2001
    16,563
    USA
    Full Name:
    Hugh G. Rection
    Here is the link to the procedure:
    http://www.cameragear.com/ec/gearbox.htm

    That top bolt is a tough one to remove...once you do crack it loose, put a little anti-seize on the threads so it will be easier next time.

    Careful on the anti-slip additive...too much and your synchros will complain.

    check the yellow pages in your phone book, most larger cities have tool stores. I use a regular metric Allen wrench and put a wrench on it...
     
  7. carlrose

    carlrose Formula Junior

    Nov 25, 2003
    291
    Hi lee,

    Grainger supply 12mm hex on socket for about $12. Probably one in your town. Went through similar experience. Buy a high-quality hex socket (as this) you don't want to ruin drain plug.

    :) Carl
     
  8. atheyg

    atheyg Guest

    I bought a 3 size 1/2" drive hex socket kit from Autozone for $7, it has 12mm-14-and 16mm I believe, they also have a single 10mm for the bottom drain plug,the overfill and top gear fill are 12mm in my 328
     
  9. Dale

    Dale F1 Veteran

    Oct 7, 2003
    5,211
    uk
    Full Name:
    Dale Juan
    Hi all bmw's use a lot of these size keys on there diffs and g/boxes,so if you know any diy or bmw techs they may be able to help with the drain/level plug keys,if it was me id without doubt remove that gear box sump(no matter how hard it is to remove and no matter how clean or dirty the oil coming out is) and wash it out,and when filling the transmission the car should be on level ground,
    cheers
    Dale.
     
  10. Lee-'78_308

    Lee-'78_308 Formula Junior

    Jan 14, 2003
    275
    Maryville, TN
    Full Name:
    Gary Lee Pierce
    Thanks a lot everyone. Excellent information as usual. I would LOVE to clean the sump, but wouldn't that require a sump gasket?

    I will look for a Grainger Supply here in Knoxville, TN right now...thanks again, all.
     
  11. peterp

    peterp F1 Veteran

    Aug 31, 2002
    6,006
    NJ
    Full Name:
    Peter
    I also bought the 3 piece 1/2" allen socket set from AutoZone for about $7. Surpisingly, this is a great, high quality set. I typically buy only Craftsman, but this was an emergency purchase because I was halfway through the job when I realized I needed the socket. I think that the quality of these sockets is easily as good as Craftsman (which isn't as good as it used to be). I also don't think that Craftsman doesn't make this size allen socket.
     
  12. Lee-'78_308

    Lee-'78_308 Formula Junior

    Jan 14, 2003
    275
    Maryville, TN
    Full Name:
    Gary Lee Pierce
    OK. I did finally get the gearbox fill plug out with the parts from Autozone. Thanks!

    Then I couldn't find the transfer case fill plug in the top of the engine. I followed the link above and the picture shows the removal of the rear tire. Well, no wonder I couldn't find it!

    So I'm going to do that now.
     
  13. ham308

    ham308 Formula Junior

    Nov 3, 2003
    358
    NE Switzerland
    Full Name:
    Richard Ham
    I hope your transfer case filler plug comes out easier than mine. I could not believe the amount of force required. In the end I think it was soaked in WD40 overnight and then it required a 1 metre extension bar and a large hammer.

    Still maybe that was unusual. :)
     
  14. 4re gt4

    4re gt4 Formula 3

    Apr 23, 2002
    2,279
    Roseburg, OR
    Full Name:
    Hans E. Hansen
    1) The transfer gear fill plug is on, uh, the 'rear' of the clutch. Left side. You shouldn't have to take the wheel off. It's in plain sight from above.

    2) Try w/o the posi additive first. Most are using the 75W90NS as-is (I am) w/o any differential probs. Dave H had to add a bit, tho. Your trans syncros are better off w/o it.
     
  15. Lee-'78_308

    Lee-'78_308 Formula Junior

    Jan 14, 2003
    275
    Maryville, TN
    Full Name:
    Gary Lee Pierce
    this is driving me nuts. I cannot find the transfer case fill plug from the top. I will take a pic and post it for add'l help...
     
  16. f355spider

    f355spider F1 World Champ
    Rossa Subscribed Owner

    May 29, 2001
    16,563
    USA
    Full Name:
    Hugh G. Rection
    Ham308,
    The top plug on the transfer case seem to all be hard to remove....do apply a little anti-sieze, which should make things easier next time.
     

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