Re: Need some 4speed help
[Re: lewtot184]
#2989665
11/27/21 07:05 PM
11/27/21 07:05 PM
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Joined: Jan 2013
Posts: 289 St.Pete,Florida
lancer493
enthusiast
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enthusiast
Joined: Jan 2013
Posts: 289
St.Pete,Florida
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Two things come to mind here, but a little clarification may help. You neglected to specify whether the trans fails to pull out of first gear on a high rpm shift or rather it only gets to a neutral position. The gears in a big mopar 4spd are bigger and heavier than a Muncie or Borg Warner T10 GM trans therefore as rpm increases it is a bigger job for the tapered cone brass synchro rings to slow down the next coming gear. GM transmissions shift like butter at high speed, but are much weaker than the big Mopar gear box. My guess would be a worn or cracked brass synchro ring on 2nd gear or grinding burrs on the 1st gear iron teeth that are integral to the gear itself. Those teeth can get to look like the starter ring gear teeth on a flywheel when they develope a burr on the edge of the teeth when the drive fails to engage properly, making a grinding sound.When that happens the starter drive gear can't pull out of the flywheel when the engine cranks or starts to run.This can happen to transmission gears in rare occassions. I would take a second look at ALL the syncro components in the 1-2 synchro assembly. I think you could get a good look just by pulling the side cover,but you may not be able to make a good check to see the actual engagement fit of the brass ring to the cone of the actual gear. The brass synchro ring should not totally butt up to the teeth on the actual gear. If that happens the ring has no ability to stop the gear effectively,especially at speed.This is why Mopar 4spds were slick shifted for drag racing, eliminating the synchronizing effect,but not at all street worthy, just power shifting. Bill
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Re: Need some 4speed help
[Re: lancer493]
#2989696
11/27/21 08:55 PM
11/27/21 08:55 PM
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Joined: Jul 2011
Posts: 781 wine country
8urvette
OP
super stock
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OP
super stock
Joined: Jul 2011
Posts: 781
wine country
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Two things come to mind here, but a little clarification may help. You neglected to specify whether the trans fails to pull out of first gear on a high rpm shift or rather it only gets to a neutral position. The gears in a big mopar 4spd are bigger and heavier than a Muncie or Borg Warner T10 GM trans therefore as rpm increases it is a bigger job for the tapered cone brass synchro rings to slow down the next coming gear. GM transmissions shift like butter at high speed, but are much weaker than the big Mopar gear box. My guess would be a worn or cracked brass synchro ring on 2nd gear or grinding burrs on the 1st gear iron teeth that are integral to the gear itself. Those teeth can get to look like the starter ring gear teeth on a flywheel when they develope a burr on the edge of the teeth when the drive fails to engage properly, making a grinding sound.When that happens the starter drive gear can't pull out of the flywheel when the engine cranks or starts to run.This can happen to transmission gears in rare occassions. I would take a second look at ALL the syncro components in the 1-2 synchro assembly. I think you could get a good look just by pulling the side cover,but you may not be able to make a good check to see the actual engagement fit of the brass ring to the cone of the actual gear. The brass synchro ring should not totally butt up to the teeth on the actual gear. If that happens the ring has no ability to stop the gear effectively,especially at speed.This is why Mopar 4spds were slick shifted for drag racing, eliminating the synchronizing effect,but not at all street worthy, just power shifting. Bill It comes out of gear fine, then only goes to neutral. Then can be fored into 3rd or 4th. but not second.
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Re: Need some 4speed help
[Re: 8urvette]
#2989712
11/27/21 10:10 PM
11/27/21 10:10 PM
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Joined: Dec 2004
Posts: 10,554 Rittman Ohio
fourgearsavoy
I Live Here
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I Live Here
Joined: Dec 2004
Posts: 10,554
Rittman Ohio
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The syncro teeth rarely look bad but they do wear out on the cone. The ring has to grab the cone on the the gear to slow it down. You need to look at new brass and de-glaze or scuff up the cone on the gear so it has a new surface for the ring to grab onto. Also double check your shift linkage adjustment because if you are shifting at higher RPM you are probably pulling the lever faster and it has to be perfect . I was just re-reading your original post and I see you are using a dual disc clutch. I tried a Mcleod Street-Twin in my Savoy and it would not get a clean release for any kind of power shifting. My Richmond box when it was stock it wouldn't power shift worth a crap with that clutch in it. Switched over to a single metallic disc and it shifted like butter. The 2 discs don't slow down enough at high RPM's for a clean 1-2 shift Gus
Last edited by fourgearsavoy; 11/27/21 10:20 PM.
64 Plymouth Savoy 493 Indy EZ's by Nick at Compu-Flow 5-Speed Richmond faceplate Liberty box Dana 60
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Re: Need some 4speed help
[Re: 8urvette]
#2989744
11/27/21 11:45 PM
11/27/21 11:45 PM
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Joined: Aug 2003
Posts: 43,195 Bend,OR USA
Cab_Burge
I Win
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I Win
Joined: Aug 2003
Posts: 43,195
Bend,OR USA
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Clutch adjustments can cause that by not having enough clearance between the clutch disc and flywheel when the motor is revved up and you're shifting it with the clutch pedal There is waffle spring between the two halves of the clutch plates on street and strip disc that is not used on the race disc. Look at yours and if it has that waffle spring in it try a race disc next Good luck, let us know what you find
Last edited by Cab_Burge; 11/28/21 07:23 PM.
Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
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Re: Need some 4speed help
[Re: 8urvette]
#2989755
11/28/21 01:45 AM
11/28/21 01:45 AM
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Joined: Jul 2008
Posts: 609 Boise
Moparteacher
mopar
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mopar
Joined: Jul 2008
Posts: 609
Boise
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When you get it apart run your finger over the fine teeth (grooves) on the inside of the brass, perpendicular to the grooves. They should catch your skin as if you was running them over the sharp edge of razor blades. If they don't catch the skin, or they feel smooth, reflect light off the flattened lands (plateau) then they are garbage.
The brass synchronizer ring works like a cluth to slow, stop and match the speeds of the following componenets (clutch disc(s), input shaft, counter gear, and all three speed gears. That's a lot of mass. It must match the speed of then output shaft, hubs and sliders being driven by the momentum of the remaining driveline.
The clutching teeth pictured do nothing to slow and match the speed of the rotating masses, they simply line-up the teech for the slider.
Try fine steel whool to polish the cone surface of the speed gears. It should polish like glass. Too course and it will shorten the life of the new brass.
The smaller, lighter the clutch disc the easier it will be to shift fast, which has already been stated.
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Re: Need some 4speed help
[Re: 8urvette]
#2989844
11/28/21 02:09 PM
11/28/21 02:09 PM
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Joined: Jul 2008
Posts: 609 Boise
Moparteacher
mopar
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mopar
Joined: Jul 2008
Posts: 609
Boise
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Yep, those are garbage. Inspect the speed gear closely. The clutching teeth should have a sharp edge all the way down to the tip. If it's rounded, and it will be, replace the speed gear. Inspect the teeth on the slider, again if the teeth are rounded at the tip or crown then replace the slider. I suspect you will need a synchro assembly that includes the hub, keys, springs, slider, and brass for 1st and 2nd. Additionally you will need a 2nd gear speed gear, minimum. Another option is to install a slick shift conversion kit from Passon Performance, and then modify either a new 2nd gear speed gear or the old gear by removing every other tooth to work with the modified slider. https://www.passonperformance.com/categories/transmission-parts/product/278-slick-shift-kitTypically only 2nd, 3rd, and 4th are modified. Liberty gears can make those changes for you or set you up with what they call a "Pro Shift Modification" to the speed gears and sliders. Or go straight to a Face Plate. https://libertysgears.com/services/face-platepro-shift-gear-modifications/Regardless, you're spending money to fix it correctly.
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Re: Need some 4speed help
[Re: lancer493]
#2989944
11/28/21 07:11 PM
11/28/21 07:11 PM
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Joined: Dec 2004
Posts: 10,554 Rittman Ohio
fourgearsavoy
I Live Here
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I Live Here
Joined: Dec 2004
Posts: 10,554
Rittman Ohio
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I don't even need to put that on the cone to see its junk. Scuff the cones and get some good brass in there from Passon or Brewers and don't buy some of the crap you see on Ebay or other retail sites, buy only from the guys who install what they sell because they wouldn't sell it if they didn't work. Gus
64 Plymouth Savoy 493 Indy EZ's by Nick at Compu-Flow 5-Speed Richmond faceplate Liberty box Dana 60
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