More 4 Speet Conversion Questions

Discussion in 'U-shift em' started by JoRion, Oct 18, 2021.

  1. JoRion

    JoRion Active Member

    Hey all,

    About a year ago, with your help, I did an auto to 4 speed swap.

    I put around 3k miles on and everything was fine. No bad sounds, shifted fine. Did some longer road trips.

    Then last week, I was driving home from work – and I'm not sure what happened – I'm pretty sure I heard a "bang" sound – then the car got stuck in gear. I could shift if I double clutched. But it wasn't fun.

    So, I haven't gotten into it yet. Will pull the transmission shortly. But wanted to get some thoughts on what to look for, and what could have happened.

    To field some questions before hand: I have a Saginaw in there currently. I know what your going to say: get a muncie... I have a Muncie, but still have highway gears... And the Saginaw was doing the job...

    Anyway, I went through and replaced all soft parts and worn hard parts when I got the saginaw. Worked great. Didn't trash it. Just used on the street. Sometimes I accelerated quickly, but nothing that I would think my 180hp 350 would tear apart.

    Currently, I can shift when the car is off, but its difficult with the car running. This would suggest clutch issues? But what would cause the clutch to suddenly have a major issue?

    Another question I have regards the pilot bushing... My crank did appear to be drilled for one. But As further research shows - my crank does have that step that some talk about. That being said. the bushing went nearly flush – only protruding slightly after instillation. And I tested the fit with an extra input shift – all was fine - trans slid right in. Could the pilot bushings protrusion cause an issue?

    Anyway, I would love to hear some thoughts, as to what could cause such a problem – from people who know far more than me.

    Many thanks
     
  2. buick64203

    buick64203 Supercar owner Staff Member

    First thing I would do is take the inspection cover off and check to see if the pressure plate is moving normally. Does the clutch pedal feel normal? I've seen the ears snap off the clutch forks.

    Are you sure you installed the throw out bearing on the fork correctly?
     
  3. JoRion

    JoRion Active Member


    I pulled the inspection cover the next day. Nothing looked abnormal. And the clutch appeared to disengage fine. I didn't inspect the fork closely. Will do so tomorrow. Also, the clutch operates fine. And if I start the car in gear with the pedal pressed – there's no jerking motions – not giving any signs that its still engaged.

    I thought the bearing was installed correctly. But I reckon I could have made an error.
     
  4. buick64203

    buick64203 Supercar owner Staff Member

    I make a quick video a few years ago to demonstrate it. It should not be put under the spring

     
  5. JoRion

    JoRion Active Member


    I am 99% sure I installed it correctly. But I'll definitely check asap.
     
  6. JoRion

    JoRion Active Member

    I crawled under today. The t/o bearing was installed correctly.

    I prepped to pull the trans. so, should be out tomorrow without a problem.
     
  7. knucklebusted

    knucklebusted Well-Known Member

    I'm far from an expert but are you getting grinding when trying to shift with the engine running and clutch in?

    Can you get it out of gear but not into the next gear?

    A broken synchro would probably cause grinding. Usually, that only affects the gear it synchronizes.

    If it is all gears and is hard to get in or out of gear at a dead stop, could it have had an oil leak onto the clutch disc? A dragging clutch would make everything difficult. It could be a front seal on the trans or a rear seal on the engine that contaminated the clutch.

    I'm curious as to what you find when you resolve it.
     
  8. TrunkMonkey

    TrunkMonkey Well-Known Member

    If it went bang under normal driving and not during shifting or hard acceleration, the bank is in the box.

    You broke a synchro or gear. Double clutching helped seed matching gears to RPM so you could shift a bit easier.

    A dragging clutch is very noticeable going into first or reverse, without "stirring" (usually going in and out of third and fourth then to first and then reverse). Not so noticeable in other gears, but an occasionally "clashing" unless it really dragging badly.

    And you eliminated release and the bearing if it starts in gear with no pulling/jerking, as the transmission's already in gear, and the issue is clashing in any gear, pointing to unhappy spinning parts.

    A pilot bearing can cause problems if it seized/binds, but would pull/jerk if you start in gear as the input shaft would be spinning with the crank.
     

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