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Rusty Rock Crusher advice needed.

Discussion in 'The Hokey Ass Message Board' started by Buzznut, Oct 30, 2013.

  1. Buzznut
    Joined: May 9, 2008
    Posts: 2,349

    Buzznut
    Member

    Been driving my pickup and the current M22 has bad synchros, so I'm going to swap it out. I have another one that is fresh rebuilt (about 8 years ago) and never used. I've been holding onto it but lost track of it in storage the last couple of years. I went to install it this weekend and the shaft doesn't turn freely by hand. A little pissed, I opened up the side plate (where the forks attach) and found a little surprise. The backside of the plate has some steel and the forks and fork clutch sleeves (is that what you call them?) are rusty. Not horribly, but surface rust. I can clean the forks by hand, but the clutch sleeves (which I cannot remove with disassembling the transmission) also have surface rust. I have NO intentions of disassembling this trans.

    Anyway, I'm trying to figure out how to clean out / flush the rust scale and get rid if the oil that has turned to sludge. Should I fill it with kerosene, gas, mystery oil, etc..? spray with brake cleaner, and then drain it? Which of these would do the least damage, or would any of them be ok? Which would remove the most scale? Will I have to reinstall new seals? Any help would be great.

    BTW: the gears and synchros and the inside of the case all look really good...there is minimal rust, but I need to get rid of it before installing this gearbox.

    Thanks guys...
     
  2. 2racer
    Joined: Sep 1, 2011
    Posts: 960

    2racer
    Member

    I would flush it with atf and run it...
     
  3. SBCWelder
    Joined: Jun 24, 2013
    Posts: 51

    SBCWelder
    Member

    If the rust comes off that easily, I wouldn't be worried about the gears. Not turning by hand makes me question the bearings though. New or not, if there's rust on the bearings they're junk.
     
  4. bgaro
    Joined: Sep 3, 2010
    Posts: 1,189

    bgaro
    Member

    surface rust shouldn't prevent you from turning by hand. sbcwelder is onto something here.
     

  5. fab32
    Joined: May 14, 2002
    Posts: 13,985

    fab32
    Member Emeritus

    Know this isn't for everyone but if it were mine I'd disassemble it, properly derust all of the internal parts and reassemble with new gaskets/seals. During the course of my drag racing days I have rebuilt 200+ of these transmissions and the whole job wouldn't take me more than an hour to an hour and a half to do the job. I made a fair share of my racing budget doing manual transmission repair. When you get to being able to do it with your eyes closed it's kinda boring.:rolleyes:

    Frank
     
    kidcampbell71 likes this.
  6. Ole don
    Joined: Dec 16, 2005
    Posts: 2,915

    Ole don
    Member

    I would fill it with fresh clean ATF on the bench and gently turn back and forth by hand to free it. Spend some time, it will save you money. If it gets to turn free in all gears, drain and flush, fill with 90 wt and go.
     
  7. I think one way or another that Trans will be coming apart weather you like it or not.
    You can do it now or after you burn it up.
    Read SBCwelders post a few times, you'll talk yourself right into taking it apart.

    Rust never sleeps.
     
  8. Buzznut
    Joined: May 9, 2008
    Posts: 2,349

    Buzznut
    Member

    I've never taken one of them apart, so it seems daunting to me. If I disassemble it and don't change anything at all, can I reassemble it without having to check tolerances or adjusting anything. The part that concerns me is getting the tolerances and specs correct.
     
  9. Rickybop
    Joined: May 23, 2008
    Posts: 9,606

    Rickybop
    ALLIANCE MEMBER

  10. falcongeorge
    Joined: Aug 26, 2010
    Posts: 18,341

    falcongeorge
    Member
    from BC

    X2. If it wont roll over, its gotta come apart. How stupid are you going to feel when the trans packs it in a couple weeks after you put it in the truck because the bearings are fragged?
     
  11. Torkwrench
    Joined: Jan 28, 2005
    Posts: 2,713

    Torkwrench
    Member

    If you decide to disassemble it, look for a copy of Pertersons "Basic Clutches and Transmissions". Back in the late 1960's to late 1970's Peterson's Publishing, (Hot Rod Mag.), printed a series of basic "How To" books, all on auto related subjects. They are all well written and illustrated.

    "Basic Clutches and Transmissions" has a section on rebuilding Muncie 4 speeds, with LOTS of photos. There are alot of good tips in these books, too. Since they are long out of print, I found my copy on Ebay. There were many other titles such as "Basic Carburation, And Fuel Systems", "Basic Chassis, Suspension And Brakes", etc.
     
  12. Buzznut
    Joined: May 9, 2008
    Posts: 2,349

    Buzznut
    Member

  13. Rickybop
    Joined: May 23, 2008
    Posts: 9,606

    Rickybop
    ALLIANCE MEMBER

  14. Maybe I'm posting the obvious but if they are in 2 gears at once they will lock up and it does sound like you're not entirely familiar with how they work. Make sure all the levers are in neutral and report back. Maybe stick an old clutch disc on the input shaft to give you more leverage to try to turn it as well.
     
  15. Mike51Merc
    Joined: Dec 5, 2008
    Posts: 3,856

    Mike51Merc
    Member

    Geez, isn't an M-22 worth a lot of money? And a rebuilt one worth even more?
     
  16. Buzznut
    Joined: May 9, 2008
    Posts: 2,349

    Buzznut
    Member

    I am very familiar with how they work...I shift one every day. It is not stuck in a gear...it was turning freely just 4 months ago or so. I rebuilt one about 18 years ago in class I took, and this one was rebuilt (by a professional) about 8 to 10 years ago. The videos have jarred my memory, I just need to crack it open and do it.

    M22 are somewhat the holy grail of early GM transmissions. I have the one in my truck and the one I'm talking about here and two M21's that I's like to rebuild or have rebuilt as well.
     
  17. SBCWelder
    Joined: Jun 24, 2013
    Posts: 51

    SBCWelder
    Member

    Good luck to ya. I think pulling it apart to check it out is the right choice. You should be happier in the long run.
     
  18. cheesegrater
    Joined: Sep 1, 2011
    Posts: 114

    cheesegrater
    Member
    from california

    Pay me now Or pay me later but a lot more hassle later
     
  19. hot rust
    Joined: Sep 18, 2007
    Posts: 779

    hot rust
    Member

    i use an older motors manual,one thru early 70's should have all the info you need to do one. there's a motors manual on e bay right now in those years i think the starting bid is 12.00 with 7.00 shipping can't go wrong with it. hope this helps hot rusthttp://www.ebay.com/itm/141232344700?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649
     
    Last edited: Mar 23, 2014
  20. my47buicksuper
    Joined: May 23, 2013
    Posts: 296

    my47buicksuper
    Member
    from sunny fl.

    I've never been into a trany till I did my 3 speed (since the trabs shop didnt know how) anyways figured it won't hurt to try myself got a book on how to rebuild it and didn't even touch it really manual tranys are very easy if you are still ify take lots of pics it helps your first time good luck
     
  21. motage
    Joined: Apr 18, 2010
    Posts: 9

    motage
    Member

    If you able to reuse the parts and carefully seperated gaskets, all your clearances and endplay should stay as they are. The only difficult areas that I remember are getting the reverse arm back on the reverse gear whe n reassembling trans. Non caged roller bearings can be held in place using wheel bearing grease or vaseline. There are 4 rows on the cluster gear and 1 row at main drive gear and mainshaft. The synchro hubs are sometimes pretty tight on the mainshaft, which you may not need to take apart if it all spins freely once away from the cluster gear. if you need to get the synchro hubs off the mainshaft a press helps or you can just bang the the end of the mainshaft on a block of wood several times, using the inertia to separate each hub.Snap rings can be squeezed back to keep them tight. Lay your parts out in order and try to keep them in order.
     
  22. Buzznut
    Joined: May 9, 2008
    Posts: 2,349

    Buzznut
    Member

    I know this is months later, but I did get the transmission completely apart and found that the bottom of the 3rd and 4th gear had been sitting in a rusty soup (partially submerged) which left some slight pitting. It turns out that this second unit is a wide ratio and not an M22. I completely disassembled and cleaned it and put it in my truck. It whines a bit in 3rd and 4th, likely from the irregular surface on a few gear teeth.

    I'm going to rebuild the M22 I took out and put it back in and keep the one I'm currently using as my backup. One thing I do plan on doing is converting the M22 from a close ratio to a wide ratio, as the deeper first gear helps a ton during take-off. I'll be replacing the entire countershaft / gear assembly and the input / 1st gear cluster in order to convert it to a wide ratio. I'm also going to install new collar, hub and synchro assemblies, new bearings and a new redesigned steel center plate. In total parts will run me around $600 and the M22 should be bullet proof behind my 400hp mill.
     
  23. CGkidd
    Joined: Mar 2, 2002
    Posts: 2,909

    CGkidd
    Member

    If you convert to wide ratio on the M22 I would be interested in the close ratio gears for my gasser project.
     
  24. Tell ya' what....I like 'em both. You are in good hands with the M22 for sure....always....but that other.....M21???......is bad ass too. My 71 442 had a stump twisting 455 and 80,000 miles on it with nothing ever done to it. Wish I still had that one. M21 took all the abuse a stupid 19 year old could throw at it, in those days. This 42 year would definitely treat it better today. Thumbs up for Muncies in Texas !!
     

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