Manual Transmission Synchronizer Ring

MolaKule

Staff member
Joined
Jun 5, 2002
Messages
22,362
Location
Iowegia - USA
What is the basic basic function of the synchronizer ring in a Manual Transmission? Guidelines for the Question of the Day: 1. No Piston Cup Lapel Pin will be awarded to the same person within 14 days of a previous award. 2. Please respond with a complete sentence. 3. Please do not post links. If a question arises as to the need for clarification, then sources and links may be requested. 4. Please, no off topic posts.
 
Last edited:
Joined
Aug 19, 2009
Messages
666
Location
Modesto,CA
The syncro will allow the collar, driven by the shift fork, to reach the same speed as the gear on the main shaft & engage the teeth in one operation of the clutch system.
 
Joined
May 14, 2007
Messages
520
Location
South Carolina
It also provides a blocking function to prevent the engagement lugs on the slider and the gear from contacting each other until they are rotating at near the same speed.
 
Joined
Dec 30, 2006
Messages
25,855
Location
Dallas,Tx USA
^^All three of the above. Basically to "synchronize" the moving parts so that the gears will mesh properly upon shifting to prevent gear crunch/grind/clash.
 
Joined
Jun 5, 2013
Messages
993
Location
Wisconsin USA
Yes to the above. A synchro eliminates the need to double clutch when shifting (another skill that used to be common, and is now lost).
 

MolaKule

Staff member
Thread starter
Joined
Jun 5, 2002
Messages
22,362
Location
Iowegia - USA
The basic function of the synchronizer ring is to create frictional torque on the cone and an indexing torque on the teeth. In a manual transmissions synchronization assembly, the synchronizer blocker ring is of special importance for shift behaviour. The synchronizer blocker ring synchronizes two transmission parts rotating at different speeds in the shortest time possible and with little effort. It is important to use dedicated, correctly designed fluids, with the correct frictional properties. The synchronizer material used on the blocker ring has a major impact on the quality of the shift feel and the durability of the gear change system. So while I was hoping for a more in-depth answer, all of you answered correctly in one fashion or another. So the Piston Cup Lapel Pin, fashioned with a special blocker ring surrounding the Cup, goes out to all who responded. approved happy
 
Last edited:
Joined
Jul 26, 2003
Messages
5,570
Location
New Zealand
Also called a baulk ring. Dunno about correct oil being that important....although it is. BMC gearboxes took SAE30 in cars, but the commercial vans like the J4 had EP90....and then the same geartrain used in the Mini and 1100/1300 took 20/50. Perhaps it was a forgiving design, but when worn would crunch into gear no matter what oil was used.
 

MolaKule

Staff member
Thread starter
Joined
Jun 5, 2002
Messages
22,362
Location
Iowegia - USA
I think the correct "dedicated" oil is very important. Since most MT gearboxes are speced for a GL-4 protection rating and require specific friction modification, I see motor oils going the way of the Flat-top V8 for use in MT gearboxes, because motor oils don't address either requirement.
 
Joined
Nov 11, 2010
Messages
9,783
Location
Saskatoon canada
Originally Posted By: MolaKule
I think the correct "dedicated" oil is very important. Since most MT gearboxes are speced for a GL-4 protection rating and require specific friction modification, I see motor oils going the way of the Flat-top V8 for use in MT gearboxes, because motor oils don't address either requirement.
I agree with you. Motorcycles for example. Most have a shared sump using engine oil which is why I love my Harley. Dedicated trans oil,dedicated primary oil to which I use a JASO rated motor oil and of course the engine. My Harley sounds like a can of marbles with certain engine oils and with others it is quiet as a church mouse. Not naming names though. My tranny had a "clunk" going into first gear using Harley's oil which is supposed to be used in all 3 holes. Putting redline shockproof in the tranny cured the clunk too. So yes molekule I hope your right and this trend carries into the mc industry as well.
 
Joined
Mar 18, 2013
Messages
496
Location
Australia
Quite right. There's no synchronisation mechanism so the lube requirements are different. The advantage of having a separate compartment for the gear lube in a MC, is that it's possible to run a dedicated gear lube without any compromises for engine lubrication requirements. The loads on a MC transmission are considerably less(though not inconsequential) than they are in a passenger car, or some other heavier vehicle. Hence in a MC transmission, drive is usually transmitted through Spur gears because of the reduced loading, as opposed to Helical gears.
 
Last edited:
Top