News

Hmmm, that's weird ..... issue with shift seal?

Discussion in 'Mondial' started by 2cam, Nov 23, 2020.

  1. 2cam

    2cam Formula Junior

    Aug 28, 2014
    634
    Austin, Texas
    Full Name:
    MikeS
    OK, this is a little strange. On Friday, I had my 3.2 out for a spin. During the course of the drive, I caught a whiff of oil all of a sudden and the shifting began to require quite a bit less effort to shift between gears. There was also a faint grind going into 2nd that hadn't been there before. Fortunately, I was only about 5 miles from home when it happened. I drove the car home, parked it in the garage, and busied myself with weekend activities that kept me away from the car. This morning I noticed a small amount of fluid on the floor beneath the car. It appears to be trans fluid.

    So, what do you guys think may have happened? What could it be? My first thought was that perhaps the internal shift seal let go allowing engine oil to pass into the trans fluid, thinning it out, and overfilling the trans leading to the leak. Unfortunately, I won't have a chance to explore it more in-depth until later this week, but wanted to get a start on potential issues to explore that may have led to those symptoms. Any ideas?

    Thanks in advance for the suggestions!

    2cam
     
  2. To remove this ad click here.

  3. moysiuan

    moysiuan Formula 3
    Silver Subscribed

    Nov 1, 2005
    2,172
    Canada
    #2 moysiuan, Nov 23, 2020
    Last edited: Nov 23, 2020
    A shift shaft seal leak internally would cause the oil and gear oil inappropriately mixing in the oil and gear sumps, but there would be no oil leaking on the floor. You might get a clue if you check the oil level, I think the engine oil goes into the gear sump, and you should be about a quart down on the engine oil if that happened. But I don't think overfilling the gearbox from an internal leak or otherwise would cause a leak on the floor, the only place for that leak to come from would be the differential seals. Other threads indicate where this happened the shift quality was worse, not easier as you report.

    The outside shift shaft seal failing would cause the external dripping, but that would be the engine oil not gearbox oil leaking, and gear oil does have a distinct smell and you suggest you have gear oil on the floor.

    My bet is your differential seals are leaking and they fling oil onto the headers. I doubt the shift seal failure would cause a wiff of oil while driving, while a differential seal failing would fling gear oil on the header and you would get the oil smell from some of it burning off. Look under the car and see if you have some oil spatter carbonized on the headers, it will be a line spattered where the inner cv joint goes into the gearbox. If the seal failed badly, I suppose you may have lost gear oil and maybe the low level did alter the shift behaviour.

    But it sounds like the car shifted fine, just with less effort. That seems odd, with or without oil in the gearbox I would think the shift effort would not change that much.
     
    2cam likes this.
  4. 2cam

    2cam Formula Junior

    Aug 28, 2014
    634
    Austin, Texas
    Full Name:
    MikeS
    Thanks Andy. I appreciate the response. I'm going to try and find some time to get under the car this weekend and have a closer look. I'll check the gearbox fluid level to see if it's over-filled and also check the diff seals as you suggest.

    Thanks!

    2cam
     
  5. AndruL

    AndruL Karting

    Apr 4, 2018
    205
    Full Name:
    AndruL
    I would also check the Clutch Slave Cylinder
     
  6. 2cam

    2cam Formula Junior

    Aug 28, 2014
    634
    Austin, Texas
    Full Name:
    MikeS
    Thanks AndruL. The clutch action feels the same and the leak isn't brake/clutch fluid, so this probably isn't it. However, I do appreciate the suggestion!

    2cam
     
  7. To remove this ad click here.

  8. hnichols

    hnichols Karting
    Silver Subscribed

    Apr 15, 2020
    81
    Chicago IL
    Full Name:
    Hugh Nicholson
    Did you figure out what the issue was? I'm curious b/c I have the same car with what might be a related issue.
     
  9. 2cam

    2cam Formula Junior

    Aug 28, 2014
    634
    Austin, Texas
    Full Name:
    MikeS
    Hi Hugh. Unfortunately, I haven't had time to trouble-shoot the issue due to a house project that we're trying to finish up this week. I'm hoping that I'll have a bit of time next week to take a look at it. I haven't started the car and warmed it up since the issue appeared last month, so not sure if the oil level is down or not. My first step will be to open up the trans fill plug and see if a surplus of fluid comes out. I'll let you know what I find out.

    2cam
     
  10. hnichols

    hnichols Karting
    Silver Subscribed

    Apr 15, 2020
    81
    Chicago IL
    Full Name:
    Hugh Nicholson
    Hi Mike -- makes sense. You're lucky that you live in a place where you can drive year-round. My car is in winter hibernation, putting all my little projects on hold. As I said I'm curious, although I think my issue has to do with the shift linkage adjustment, and yours with lubrication.
     

Share This Page