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| | | | Joined: Oct 2012 Posts: 130 'Bolter | | 'Bolter Joined: Oct 2012 Posts: 130 | I have a SM420 in my 49-3100. Transmission runs and shifts fine however the shifter lever is wobbly and I would like to fix this.
I have new replacement parts if needed - shifter lever, fulcrum pins, spring, retension cup and retention cap.
Questions before I start. Is there a rubber or plastic washer or bushing that goes under the ball on the shift lever? The fulcrum pins are press fit. How is a good way to remove and install new ones?
Thanks for any advice or help.
| | | | | Joined: Jan 2013 Posts: 1,518 'Bolter | | 'Bolter Joined: Jan 2013 Posts: 1,518 | No, Here is everything you will need to install the shifter into the top loader of the sm420.
https://www.ebay.com/itm/NP435-SM420-SM465-4-SPEED-TRANS-AX94906-SHIFT-STICK-HOLD-DOWN-REPAIR-KIT/122931100902?hash=item1c9f43bce6:g:wh4AAOSweARZdRqH&vxp=mtr
Last edited by sstock; 03/22/2018 9:56 PM.
1953 Chevrolet 3100261 cu inch, sm420, 3.55 rear, torque tube still,omaha orange, still 6 volt, RPO green glass, side carrier spare, all done In the DITY GalleryVideo of the 261 running1964 GMC 1000305 Big Block V6, sm420, the next cab off restoration
| | | | | Joined: Jan 2000 Posts: 734 'Bolter | | 'Bolter Joined: Jan 2000 Posts: 734 | IIRC, I grinded off the heads of the fulcrum pins and they slid right out. Make sure to stuff a rag down in the shifter hole so they don't fall inside the trans. Look for some rolled steel pins of the appropriate size at your local hardware store. If needed you can drill out the fulcrum pin holes to accept a slightly larger pin. The rolled pins are also sold by Novaks. They are SM420 experts.  Be advised, nothing you can do will make the shifter feel as snug and tight as a new car shifter. There'll still be alot of play but it shouldn't flop and slop around quite as bad after your new parts are installed.
Matthew 6:33 1952 Chevy 1/2-ton 3100 Late '55 235/SM420/torque tube 3.55 Dalton Highway survivor (using original 216) www.truckwithaheart.com | | | | | Joined: May 2001 Posts: 1,904 'Bolter | | 'Bolter Joined: May 2001 Posts: 1,904 | I wondered how floppy my 4-speed gear shifter was so I measured it.
Engine off and:
in neutral, the gear shift knob wobbles back and forth sideways 3 1/2".
in granny gear, 1".
in 4th gear, 1 1/2".
Mine doesn't seem excessive. It shifts just fine.
1948 3/4-Ton 5-Window Flatbed Chevrolet 34 Years. Now with a '61 261, 848 head, Rochester Monojet carb, SM420 4-speed, 4.10 rear, dual reservoir MC, Bendix up front, 235/85R16 tires, 12-volt w/alternator, electric wipers and a modern radio in the glove box.
| | | | | Joined: May 2005 Posts: 8,983 Sir Searchalot | | Sir Searchalot Joined: May 2005 Posts: 8,983 | Fulcrum pins? Are you talking about the bayonet pins for the shift cup? If they lock the cup down and load the spring, they are OK as is.
The 420 has always had a "loose" feeling. Those parts will tighten up the "throw" distances. You can't change that.
But I don't know if wobbly means rattling while driving or long throw distances or ?
Remember: if it ain't broke don't fix it. You are going to screw something up that causes you to remove the trans if not careful.
Right is right, even if everyone is against it, and wrong is wrong, even if everyone is for it. - William Penn
| | | | | Joined: Sep 2001 Posts: 29,269 Bubba - Curmudgeon | | Bubba - Curmudgeon Joined: Sep 2001 Posts: 29,269 | | | | | | Joined: Jan 2000 Posts: 734 'Bolter | | 'Bolter Joined: Jan 2000 Posts: 734 | My pins were extremely worn where the edges of the retainer had cut into them over the years, so I assumed OP's was the same. Replacing with new pins probably did more to tighten it up than new spring and cups.
Last edited by Skooter; 03/23/2018 1:41 AM.
Matthew 6:33 1952 Chevy 1/2-ton 3100 Late '55 235/SM420/torque tube 3.55 Dalton Highway survivor (using original 216) www.truckwithaheart.com | | | | | Joined: Mar 2004 Posts: 6,212 'Bolter | | 'Bolter Joined: Mar 2004 Posts: 6,212 | If a driver rested his/her hand on the shifter all the time, then the shift forks could be worn out making it sloppy... Mike B  | | | | | Joined: Oct 2012 Posts: 130 'Bolter | | 'Bolter Joined: Oct 2012 Posts: 130 | Skooter
Were your pins original? How did you remove and install the new pins?
Thanks Doug | | | | | Joined: Jan 2000 Posts: 734 'Bolter | | 'Bolter Joined: Jan 2000 Posts: 734 | Yes they were original. IIRC, I grinded off the heads of the fulcrum pins and they slid right out. Make sure to stuff a rag down in the shifter hole so they don't fall inside the trans. Look for some rolled steel pins of the appropriate size at your local hardware store. If needed you can drill out the fulcrum pin holes to accept a slightly larger pin. The rolled pins are also sold by Novaks. They are SM420 experts. Be advised, nothing you can do will make the shifter feel as snug and tight as a new car shifter. There'll still be alot of play but it shouldn't flop and slop around quite as bad after your new parts are installed.
Matthew 6:33 1952 Chevy 1/2-ton 3100 Late '55 235/SM420/torque tube 3.55 Dalton Highway survivor (using original 216) www.truckwithaheart.com | | |
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