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Technical M20 Muncie Woes Again..

Discussion in 'The Hokey Ass Message Board' started by bobss396, Jul 13, 2020.

  1. I had my M20 freshened up 2 years ago, new countershaft gear set, good used input (2.52 1st gear), converted to 1" shaft, all new normal rebuild parts kit. Shifter I've had for years, Hurst Comp Plus, took it apart 4 years back, cleaned, lubed, reassembled, new steel bushings and clips in 2018. Clutch is working well and adjustment is good.

    I was out with the car yesterday coming back from a beach cruise. Not beating on it either but giving it a little exercise. I always use the clutch, never do burnouts either. It has been shifting well, the problem came on suddenly.

    I was stopped at a stop sign, turned onto my block. It started to grind going into 3rd.. odd. The shifter lost its neutral feel, normally it will have the usual left-right play in it, this felt tightened up. It went into 4th ok. By the time I got home, it felt like it was stuck between 2 gears. Thanks to the cavalry showing up (my brother who is better at 4-speeds than I am...) stopped by. Showed him what was what, we agree the clutch is releasing.

    Jacked it up, dove under. Shifter is tight to the tailshaft. Put all the levers where they belonged. I forget what was messed up on it, but it was easy to move the levers into their neutrals. Eyeballing the 1/4" shifter adjustment hole, it seemed to be all lined up. Took it for a ride, I still didn't have the normal neutral feel to it. 1st to 2nd was good. 3rd was just a grind. I had 4th. Got home, stuck between 2 gears again, but I can back it up and move it forward, had it shut the car off in "gear" with the clutch in.

    The side cover assembly is newer from Auto Gear, fluid is Richmond GL4. So I'm doubting the issue is the side cover. I'm suspecting a bent or broken shift fork, maybe a broken snychro blocking ring and maybe one of the keys is out of it. Any ideas is appreciated.

    Later today or early tomorrow when it cools off I'll put the car on 4 jack stands. Remove the shifter boot. Put the levers where they belong, check the shifter alignment. If all of that checks out, I'll drop the levers and remove the side cover, likely by Wednesday at the latest.
     
    chryslerfan55 likes this.
  2. Dennis D
    Joined: May 2, 2009
    Posts: 851

    Dennis D
    Member

    If you are not feeling the neutral side to side movement I would look close at the shims between the plates and make sure one of them isn't blocking the movement. You may want to try soaking it with spray from some penetrating oil to see if the detent is sticking. D
     
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  3. 2OLD2FAST
    Joined: Feb 3, 2010
    Posts: 5,217

    2OLD2FAST
    Member
    from illinois

    If your transmission was in b2 gears , the car wouldn't move , period , sounds like a shifter problem to me , at least that's where I'd look first ...
     
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  4. 20200713_185023.jpg
    Thanks. Car is up in the air. Before it gets hot tomorrow, will remove the shift boot, maybe the main shifter bolt is loose. After we freed it up yesterday, it was normal for a short spell. My buddy stopped by before and I was showing him the shifter... it acted normal. I put it on ramps and actually had a neutral. So it is something erratic. Will look over the shifter alignment, look at all the lever bushings, all are Hurst track-pack. That checks out, off comes the side cover.
     
    chryslerfan55 likes this.

  5. onetrickpony
    Joined: Sep 21, 2010
    Posts: 753

    onetrickpony
    Member
    from Texas

    Many years ago I had a Hurst 3 speed shifter that acted like that. It was just plain worn out.
     
  6. 2OLD2FAST
    Joined: Feb 3, 2010
    Posts: 5,217

    2OLD2FAST
    Member
    from illinois

    Its been a long time since I had a shifter apart , but I think Hurst has a spring & pin assy internally that could have broken/ come apart .
    Somebody has a you tube video on those , rebuilding etc ..
     
  7. ekimneirbo
    Joined: Apr 29, 2017
    Posts: 4,217

    ekimneirbo

    I would disconnect 1 shifter rod from the side cover lever and make sure the lever is in neutral. Then sit in the car and see how it shifts with the single lever and engine running. Then reconnect that rod and unhook the other shifter rod and see how it performs. Then pull the side cover and examine it and the forks.
     
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  8. A possibility, the shifter is from 1978, bought for my '65 Belair. I had taken it apart in 2014 and cleaned it up, lubed it. I have another identical shifter body now I think of it. I will pull the shifter if the next quote ideas don't show me anything. This is a sudden problem so I hope it is something stupid and easy to fix.

    Thanks, a good plan to isolate the problem to the 1-2 or 3-4 gates. Right now 3rd gear is just a grind. May as well start there. Heading out shortly, pretty cool out right now. I'll take off the boot, check the alignment and see if the shifter body is loose. I couldn't reach the 5/8" bolt from the bottom.
     
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  9. lippy
    Joined: Sep 27, 2006
    Posts: 6,825

    lippy
    Member
    from Ks

    I would start by checking shifter adjustment. Lippy
     
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  10. Johnny Gee
    Joined: Dec 3, 2009
    Posts: 12,603

    Johnny Gee
    Member
    from Downey, Ca

    Makes me think of when I had 3rd gear grind once. But I didn't have shifter not feeling right like you describe but I'll go on. My issue was a wallowed out pilot bearing even though center line alignment was a good. Could it be your bell housing isn't indexed correctly and 3rd gear and roller bearings has finally just had enough to show beginning signs of failure?
    upload_2020-7-14_7-29-35.jpeg
     
    chryslerfan55 likes this.
  11. The shifter alignment checked out earlier today. It still felt like it was in the shifter, the neutral position sometimes is good, sometimes not. I pulled the shifter and looked it over, pulled the inspection plate, I was expecting to see a broken roll pin. Looked at all the bushings which were new 4 years ago, new clips too. No holes egged out. I cleaned all the rods and put the levers back on, all lubed up. Tomorrow I will take the shifter body apart, clean everything and look for worn out parts.

    Johnny Gee, the bell housing has been on 2 other engines of mine and is a stock '55 Chevy unit. If the shifter looks okay, I will likely pull the M20 out. I'll at least replace the disc and look at the pilot bushing. I'm supposed to get help tomorrow night for a couple of hours. It had been shifting well since I had the box freshened in 2018, the problem came on suddenly.
     
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  12. seb fontana
    Joined: Sep 1, 2005
    Posts: 8,444

    seb fontana
    Member
    from ct

    Stick the alinement pin in an check side play of shifter levers, you don't want much, like about .010. The wavy shims should be keeping the levers snug, not tite. Some times you can dissasemble shifter and put a little more wave in the shim, add a shim or reduce through bushing length (7/16 bolt) and end spacer (3/8 bolt) to give housing a little more "crush" but mostly to make sides of body parallel.
     
    bobss396 likes this.
  13. 2OLD2FAST
    Joined: Feb 3, 2010
    Posts: 5,217

    2OLD2FAST
    Member
    from illinois

    Google " Hurst shifter/you tube" , Paul Gangialosi ( spl) he's got a number of 4-speed related videos
     
    bobss396 likes this.
  14. I had a Hurst comp plus shifter that was a pain to get into reverse. Took it apart, everything looked good. Still had the problem. Pulled it again, replaced the little slide shims the levers slide against, lubed it, aligned it and still would not go into reverse. Borrowed another shifter from a buddy and slapped it on the car and it worked perfect. Sometimes there is just something worn that you cant see on those Hurst shifters.
     
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  15. This is what I'm thinking. Something I cannot see that is wrong. I have to drop my daily off for service then will dive into the shifter body. There is one part of the shifter the videos I've seen do not recommend taking apart. But I'll lay the parts out, clean and reassemble. I have another shifter, same one that I could use, condition unknown. I have the Muncie book and it goes into good detail on the shifter.
     
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  16. pitman
    Joined: May 14, 2006
    Posts: 5,148

    pitman

    Will look fwd to what you find, good methods listed here.
     
  17. Have yet to drive it, had a little help earlier. Swapped out the shifter for another one I had. It looked good and we figured... wot the hell. It statically shifts better and we took our time adjusting it.

    We determined that the side cover detents worked ok. Put the trans in 3rd gear, tried to engage 1st and 2nd and couldn't do it. Put it in 1st, tried 3rd and 4th. So the side cover is good, probably nothing broken inside. I'll know when I drop it down tomorrow and try it.
     
  18. Linkage is exactly where I would look first sounds like worn out spring clips could be creating slop.
    causing binding and other mis alignment problems cheap easy fix and its way faster than pulling the trans & everything apart.
    If you have not changed them in the past do so, inspect linkage rod adjusting buttons and washers for wear. All would contribute to similar problems
    Most shifters regardless of manufacture share the same WEAR areas that can and do cause your explained troubles.
    What my experience is a small amount of play over here can be way out at the linkage rods other end.


    Second I would look at the shifter BODY and take it apart (depending on the model) inspect for wear bent shift body lever if nothing noticeable clean lube & reassemble. Sometimes rust/dirt can cause jamming/friction
    Because you already say the trans was refreshed recently I would look at pulling it apart only as a last resort
    *hurst diagram just for exploded view example but most linkage setups are similar.*
     

    Attached Files:

    Last edited: Jul 16, 2020
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  19. Mimilan
    Joined: Jun 13, 2019
    Posts: 1,230

    Mimilan
    Member

    I'll ask you this............Do you downshift into 1st when coming to a stop?

    Muncie's don't have detents for reverse gear in the tailhousing [which is next to 1st on the shifter]
    You old shifter could be catching 1st and reverse at the same time [just touching reverse enough to grind]
    Back it in and out of your driveway a couple of times
     
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  20. 2OLD2FAST
    Joined: Feb 3, 2010
    Posts: 5,217

    2OLD2FAST
    Member
    from illinois

    Muncies do indeed have a spring loaded / ball bearing detent in the tailshaft housing ..
     
  21. Mimilan
    Joined: Jun 13, 2019
    Posts: 1,230

    Mimilan
    Member



    On a Muncie you can select 2 gears at once , if one of them is reverse gear [the reverse gear selector is not connected to 1-4 gears lockout detents]
    So a poor shifter can cause 2 gears to catch.

    If the detent "combs" inside the side cover are in good working condition, it is impossible to select 2 forward gears together [even with a poor shifter]
     
    chryslerfan55 likes this.
  22. Thanks all. Likely it is the old shifter, I cleaned it 4 years ago and lubed what I could reach. It always had the inspection cover on it, the internals look clean, no excessive dirt or grit. So probably one of the compression springs is broken, I have to take it apart.

    I never shift to first when coming to a stop. The shifter I bought new in 1978 and had it in a few cars and trucks, it may just have too many miles on it and is worn out. There is a pin that takes the 2 roll pins, those can wear and cause problems. The correct rebuild kit is around $135.

    I have to get under the car while I have it elevated to check a few things and give it a proper greasing. The 2 guys helping me are confident that the shifter we installed is an improvement.
     
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  23. 2OLD2FAST
    Joined: Feb 3, 2010
    Posts: 5,217

    2OLD2FAST
    Member
    from illinois

    Im not arguing. whether or not reverse & a forward may be engaged together , simply that your statement saying reverse has no detent is incorrect !
     
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  24. Mimilan
    Joined: Jun 13, 2019
    Posts: 1,230

    Mimilan
    Member

    You are arguing face it! Your statements or arguments do not contribute one bit to helping the OP's original problem
    Reverse gear does not have a lockout detent. [1st - 4th does]

    Instead of being an annoying "grammar nazi" why don't you learn to read everything in it's full context.

    upload_2020-7-17_9-31-44.png

    My apologies to the OP for this thread getting "derailed"
     
    Last edited: Jul 16, 2020
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  25. brigrat
    Joined: Nov 9, 2007
    Posts: 5,615

    brigrat
    Member
    from Wa.St.

    Detent ball & spring, I wouldn't call it a lock out persay! smileyface!
    The only lockout I would call a lockout would be in the shifter mechanism, which could fail I suppose.
    s-l400.jpg
     
    Last edited: Jul 16, 2020
  26. Relax gents.. car is back together and the new-old shifter works great, like night and day. Greased the u-joints, changed the posi fluid, adjusted the rear brakes, lubed the front end, topped off the air pressure. A big relief that the transmission is good.
     
  27. 2OLD2FAST
    Joined: Feb 3, 2010
    Posts: 5,217

    2OLD2FAST
    Member
    from illinois

    Thanks brigrat , you can't educate with a stump !LOL
     
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  28. 2OLD2FAST
    Joined: Feb 3, 2010
    Posts: 5,217

    2OLD2FAST
    Member
    from illinois

    Good for you , glad it wasn't worse !
     
    bobss396 likes this.
  29. 2OLD2FAST
    Joined: Feb 3, 2010
    Posts: 5,217

    2OLD2FAST
    Member
    from illinois

    Correct information comes in correct language , I see NOW its a LOCKOUT detent , huge difference
     
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  30. DDDenny
    Joined: Feb 6, 2015
    Posts: 19,143

    DDDenny
    Member
    from oregon

    Glad it wasn't something wrong in the transmission Bob.
    Long live the Muncie 4 speed!
     

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