360 6 speed, only 5th gear grinding | FerrariChat

360 6 speed, only 5th gear grinding

Discussion in 'Technical Q&A' started by Kinks360, Oct 22, 2010.

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  1. Kinks360

    Kinks360 Rookie

    May 2, 2010
    31
    GTA
    Full Name:
    Kink
    Moving this post from the 360/430 section hoping that I may get some more advanced tranny help on the problem.

    Ok so this started about a month ago and I thought that it may be the 5th gear synchro, but in looking at a parts break down it looks like 5th and 6th gear use the same synchro? If this is true then should I not have problems going into 6th as well????
    If I pause a few seconds before shifting into 5th it falls in smoothly and absolutly no problem going into 6th. This happens when up shifting or down shifting.
    Or is it possible that there is something else wrong in the transmission causing this???

    Car has 17,000 miles and is an 02, it has the original clutch from the history on the car that I can find (car was purchased beginning of this year), clutch will be changed this winter as I,m having the pedal fade at high rpm's, (Don't think that this is causing it as it happenes even at lower rpm's).


    Proceedures already performed
    -shifter bushing
    -cable adjustment
    -gearbox oil changed

    Thanks in advance for the help.

    Cheers,
    Kink
     
  2. portogts

    portogts Formula 3
    Owner Project Master

    Aug 31, 2008
    2,344
    Maia-Portugal
    Full Name:
    Vitor Sousa
    #2 portogts, Oct 22, 2010
    Last edited: Oct 22, 2010
    Hi ...

    5th and 6th use the same sliding sleeve but use diferents synchro rings and synchro cones.

    When you engage 5th gear you move the sliding sleeve over the synchro ring and synchro cone making the selected pinion stop. The synchros are used as a clutch.

    When you select 6th gear the sliding sleeve with travel to the opposite side and do the same.

    If the syncrhos are worn they will not stop the pinion and what you hear are the teeth of the sliding sleeve grinding against the teeth of the pinion/synchro.


    Probably the synchros are worn for any reason on 5th gear...

    All the best
     
  3. Mitch Alsup

    Mitch Alsup F1 Veteran

    Nov 4, 2003
    9,727
    What portogts is trying to say is that although the synchros are very close together on the same mountings,

    You can wear one out without wearing out the toher.

    You can also wear out the sliding sleves making the gears hard to select when the tranny is cold, but after warming up they shift just fine.
     
  4. speedy1wrc

    speedy1wrc Rookie

    Sep 29, 2010
    49
    Buffalo, NY
    Full Name:
    Mark Wetzel
    Also the gear may not be engaging correctly due to a "speed" mismatch. The syncros and teeth must "sync" and sometimes the gear oil can affect this. What are you you using for gear oil?

    We see this a lot with people changing to a very slippery synthetic gear oil from a conventional. The blocking gears then are so free that they spin at a different speed than the cluster and they don't engage smoothly. An excellent gear oil can sometimes be a bad thing. Depending on the application and the particular oil we have come up with a few blends to help this. For example for older Audi gearboxes we found a combination of 2 qts of Redline MTL90 to 1qt Redline Shockproof Heavy behaves like a conventional oil in terms of lining up the blocking gears, but is still a much better gear oil overall.

    Or..as above the syncro may be bad. Kind of unusual for upper gear syncros to go bad before lower gears though. We see 2nd going out as the most common.
     
  5. f355spider

    f355spider F1 World Champ
    Owner Rossa Subscribed

    May 29, 2001
    18,044
    USA
    So that begs the question of the OP.....

    1) What was the original gear oil used?

    2) What gear oil was used when it was changed?
     
  6. No Doubt

    No Doubt Seven Time F1 World Champ

    May 21, 2005
    72,740
    Vegas+Alabama
    Full Name:
    Mr. Sideways
    Your worn clutch is exacerbating your problem. A non-slipping clutch and a heavy gear oil could give you perhaps thousands of additional miles before you'll have to tear down the tranny to replace your failing synchro, or you could just do the work now on both the clutch and tranny, then use the correct gear oil instead of a heavy gear oil.
     
  7. relhakim

    relhakim Rookie

    Oct 22, 2010
    1
    I had the same problem with his 360...The problem is its very hard for a mechanic to adjust the cables back perfectly for it to allow the shifter to go in smoothly. one of the employees at I95 Exotics which is an exotic car rental in Miami solved the problem for me simply by removing the shifter cover and sanding the edge so it would move a bit more to the right... and guess what IT WORKED. in the begining i didnt wanna sand or grind anything but i ran out of options and even the dealer didn't really know what was wrong.. sometime they tell me its the cable , or the transmission or sync or the clutch which showed me that they didnt really know what is going on.

    I thank the guy at I95 Exotics for solving my problem.

    you guys should check them out if you ever go to Miami and wanna drive something nice like a ferrari or a lamborghini or a bentley...

    Check their website.... www.i95exotic.com
     
  8. SoftwareDrone

    SoftwareDrone F1 Veteran
    Sponsor Owner

    Jan 19, 2004
    7,858
    San Jose, California
    Full Name:
    Mike
    I had the exact same problem and did the same fix as the previous poster. I had 20 mil shaved off of the right side of the reverse lockout block (located right under the stainless gate). Works perfectly now. When the car is sitting still, move the shifter all the way to the right and see if the shaft actually touches the right wall of the gate. If it does not, then the block underneath is holding it up. Sometimes simply repositioning the lockout block a little to the right before retightening the gate screws will solve the problem, but sometimes you need to shave that little extra off. Remember that you don't want to move the block so far to the right that your 1st-2nd gears start to suffer.
     
  9. Kinks360

    Kinks360 Rookie

    May 2, 2010
    31
    GTA
    Full Name:
    Kink

    I thank everyone for there replies so far and offer some comments to some of the questions;

    -Gear oil that the dealer used was 75W90 and after this was done the shifting was fine for the first 4000 miles.
    -The shifter does hit the end of the gate

    To me it now souds like a tranny problem, why 5th gear and not the usual 2nd i cannot explain. I don't understand how it can be a cable adjustment as I have no trouble getting it to go to 5th gear, it just grinds immediately unless i pause a moment before putting into 5th.

    Thanks
    Kink
     
  10. Pantdino

    Pantdino Formula 3

    Jan 13, 2004
    2,069
    Full Name:
    Jim
    What kind of 75W90 oil was used, exactly?

    With the earlier transaxles (from the 1970's and early '80's) the feeling is that Red Line 75 W 90 NS is the best choice because it does NOT have the friction reducers almost all gear oils have. These friction reducers are included so the limited clutch plates do not bind, but they make the oil so slippery that the synchros don't function well.

    If you get noise from your limited slip plates (sounds like a moaning noise when you turn) with this oil you can add small amounts of Limited Slip Additive until it goes away.
     

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