308 differential slipping? | FerrariChat
Buy

308 differential slipping?

Discussion in 'Technical Q&A' started by myriadpro, Nov 25, 2004.

This site may earn a commission from merchant affiliate links, including eBay, Amazon, Skimlinks, and others.

  1. myriadpro

    myriadpro Rookie

    Nov 25, 2004
    2
    #1 myriadpro, Nov 25, 2004
    My 1978 308 GTS with around 23,000 miles has just stopped moving! There have been three occasions in the last few weeks where the motor revs up and the car didn't change speed and when the revs came back down, everything was normal. Once it happened on a country road going about 50 up hill when I tried to maintain speed. The next time it happened as I went around a turn and it came back after the car straightened. This last time I went around a turn and it slipped and never caught again. It stopped moving no matter what gear or engine speed. I could select gears and reverse and it didn't seem like the clutch was broken. So, I think it's the clutches in the differential and not the main clutch. The car had a sticky caliper last year and I drove it for a while before fixing it. The other caliper had started sticking awhile back and I put it off. I think the sticky brakes have caused the differential to work excessively and worn the clutches prematurely! Does anyone have any experience with this? Can anyone recommend a link that covers differential repair? Thanx in advance!
     
  2. F40

    F40 F1 Rookie

    Apr 16, 2003
    3,230
    AZ
    #2 F40, Nov 25, 2004
    The sticking brakes could have lead to premature wear, just like running a tire of larger size on one side of the car then the other. Perhaps your LSD is toast? Or are these cars open diff?
     
  3. Bandit

    Bandit Formula Junior

    Dec 21, 2003
    493
    Central MS
    Full Name:
    Mike B.
    #3 Bandit, Nov 25, 2004
    It sounds like a main clutch problem to me. Even with the differential clutches slipping, at least one wheel should have power going to it. The parts diagram looks like a standard plate type limited slip differential with spider gears. It should act like an open differential with the clutches worn out. Unless the splines on the driven shafts were completely stripped the car should still drive fine.

    I would seriously suspect a worn out main clutch, but if you really think it is the differential, jack the rear of the car up and see if one wheel or the other spins freely with the car in gear. If one wheel spins and the other doesn't, you have a broken or stripped shaft in the differential or hub.

    Also, have you ever adjusted the clutch? I understand on the 308 that as the clutch wears, it will eventually use up all the free play in the pedal and cause the clutch to not engage.

    A sticky caliper should not wear out the differential clutches. The clutches wear when one wheel spins faster than the other. Sticky calipers would put stress on the differential as a whole, but if it was bad enough to cause problems I would think the caliper and rotor would get hot enough to cause a fire at the wheel before the differential wore out.
     
  4. matteo

    matteo F1 World Champ

    Aug 1, 2002
    13,748
    On a plane somewhere
    Full Name:
    Heir Butt
    #4 matteo, Nov 25, 2004
    Jack up the rear of the car.

    With the e-brake off and the car in netural, spin the wheels, If they move, meaning if you spin one, the other will move on it's own, then your diff is fine.

    I agree with Bandit, it sounds like your main clutch. Flywheel might be toast as well.
     
  5. myriadpro

    myriadpro Rookie

    Nov 25, 2004
    2
    #5 myriadpro, Dec 5, 2004
    Thanks for all your input. I've been out of town since my original post and finally got a chance to jack up the car today and see what was up. The left innner CV joint isn't there anymore! It must have had just the right combination of debris to drive the car when it "slipped" till it finally let go. The good news is.... it's fairly easy to fix!
     

Share This Page