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Just swapped standard trans oil in. Crunching on shifts

Discussion in 'Drivetrain' started by Alexg, Jul 30, 2015.

  1. Alexg

    Alexg Well-Known Member Donated!

    Hey all,

    So i just swapped out my 3 yr old auto fluid, clean as clean obviously with just some small flecks in the bottom. It had more-than-i-thought gear noise while off the throttle and with 400k on the clock, so i thought it was time to put something thicker in!

    Reading that 80w90 is the trick, I got some semi-syn Nulon 75w90 (No 80w in the semi synth, and i wasnt spending 60 bucks on full synthetic) its decent stuff, seemed smooth when i put it in yesterday and less gear meshing noise :D

    HOWEVER, Today im getting some issues on downshifts. I need to drop revs more and match revs much more closely and its crunching often when shifting down, especially second.

    Didnt do this as much on the ATF, not sure whats going on, though im sure my syncros are worn anyway but the thicker oil *should* have helped that?

    I also get a weird issue sometimes upshifting where it just slams straight in with a slight crunch and no resistance, as opposed to that "resistance" you normally feel as you go through the gate.
    As a general rule i dont shift like a rally driver with a dog box, i do try to treat it nicely as a side note :p

    Any recommendations on fluid? Nulon also does a "Smooth Shift" additive that i know does well.

    I dont have as much experience with the boxes as the engines, so any help on these is appreciated.


  2. Alexg

    Alexg Well-Known Member Donated!

    Just realised this is in the wrong section, i probably should have posted in Diagnosis.

    I'll also try bleeding my clutch line ;)
    Last edited: Aug 3, 2015
  3. eNtraxGT88

    eNtraxGT88 Well-Known Member Donated!

    What type of fluid was it? GL-3/GL-4/GL-5?

    I personally have been a fan of Redline MT-90.
  4. Alexg

    Alexg Well-Known Member Donated!

    This is the oil

    It is a GL5 apparently.

    I have bled the clutch line too, jeeeeeeeeeeeeeeeEEEEESUS. I dont think its EVER been changed. The reservoir looked like it was full of swamp water.

    Ive also added Nulon G70, PTFE gearbox juice, not sure on difference yet.

    2nd is definitely an issue though. I swear it wasnt this bad on the old ATF i had in there, but im not sure if its just the "i changed something and now i notice a difference" syndrome.

    This oil should be far better in every way, so i dont know whats going on, or if my box has just reached the point :/

    Ive also discovered a *New* gearbox filler hole. Theres a Allen key bolt to the right of the reverse sensor bolt that Stig recommended to fill through.
    Well i pulled that off as i didnt have a spanner big enough for the other one, and the proper filler hole underneath just would not come undone!

    The Allen key bolt needs the airbox unbolted, but after that it was a breeze.
    Last edited: Aug 2, 2015
  5. eNtraxGT88

    eNtraxGT88 Well-Known Member Donated!

    how's your clutch engagement? is it too low/too high? it should be dead in the middle so your clutch has enough time to release when you shift gears but also have enough clamp force when you left off the pedal.
  6. Alexg

    Alexg Well-Known Member Donated!

    The clutch starts grabbing about two pedal spaces off the floor and when you clutch in it just starts slipping after about two pedal spaces from when the play is taken up. So It seems that the clutch has a lot of in between, but it always has.

    I don't have issue up shifting second or in any other years really, its only when I downshift into second.

    All of today I had to drop to no more than 30kmh AND match revs to get a smooth shift, or it grinds before dropping in. I've started skipping it all together and slowing enough to drop to first when I can actually.

    Makes me worry I might be in for a new box, its happened so suddenly though and I would expect synchros to slowly cause more trouble as they wore out rather than losing it within the space of a week.
  7. Alexg

    Alexg Well-Known Member Donated!

    Ok well I've adjusted my clutch freeplay a bit and it hasn't improved (I had lots of free play)

    Unless the semi synthetic is "too slippery" then I'm really down to 2nds synchro being worn out.

    I can actually shift into 1st from 3rd easier than into 2nd, which is not promising.

    As a last resort I will put my old oil back in and see If it changes. I can rule it out then at least.

    And then its just down to swapping my box, I didn't want to do this yet >.<
  8. eNtraxGT88

    eNtraxGT88 Well-Known Member Donated!

    Perhaps the ATF had some gunk in there that was hiding the crunch and with the new oil, cleared it up, but now have this crunch.

    Who knows. Box swap isn't too hard, just annoying and time consuming.

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