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#54363 01/03/2006 2:47 AM | Joined: Sep 2003 Posts: 343 Member | | Member Joined: Sep 2003 Posts: 343 | I got my SM420 Manual 4-speed transmission rebuild kit from Novak and I have a question regarding the replacement synchro's they sent. The new synchro's are not an exact match to my old ones in that the teeth are some what differently shaped. If you look at them on edge the individual teeth look like an outline of a house. The difference is the "house" is shorter on the new synchro's compared to the old synchro's. I know this might sound a bit confusing, so here is link to few pictures that illustrate what I am talking about: http://community.webshots.com/photo/109000222/534916438GAmHqG The questions: is this new synchro a better design compared to the old synchro and will work OK in my transmission?
1954 GMC 1/2-ton Longbed
1971 Pontiac LeMans Sport
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#54364 01/03/2006 3:54 AM | Joined: Jul 2004 Posts: 5,708 'Bolter | | 'Bolter Joined: Jul 2004 Posts: 5,708 | cujo8,
I'm going to digress a tad, back to the gear lube thread on SM420's. Several members pointed out that one of the extreme pressure additives (sulphur) in a GL-5 lube would "eat those synchros up". I must say, I am having a hell of a time figuring out which of the two rings you have pictured is old and which is new. :rolleyes:
Stuart | | |
#54365 01/03/2006 1:52 PM | Joined: Sep 2003 Posts: 343 Member | | Member Joined: Sep 2003 Posts: 343 | Stewart, The old one is the darker one, but I agree that this one is in quite good condition. The other old synchro (3rd-4th) is quite worn though. I can safely say that my SM420 has never seen and GL-5 gear lube, since the muddy-brown gear oil that was in this trany looks like it has been in there long before GL-5 was introduced.
Thanks. Jim
1954 GMC 1/2-ton Longbed
1971 Pontiac LeMans Sport
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