64 Diff. Code?
#3
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The Julian date code (3 3 4) pretty much confirms that it's a '78 or '79 3.55 Posi ("OH") axle, made on the 334th day of the year. The casting date will be on the driver's side, partially hidden by the front of the strut rod bracket.
#6
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Yup - the 464910 rear cover was used in '78-'79, with the 7/16" rear spring retainer plate bolts (vs. the 1/2" bolts used from '63-'77) to accommodate the '78-up 2-1/4"-wide spring.
#9
Intermediate
Thread Starter
JohnZ,
As you stated in an earlier post, there is a P-code on the side of the muncie 4-speed in my car.
It is: P8T18
If I understand it correctly that means it was built on December 18th,
1967 , for a 1968 car.
Still not sure if it is a M20, M21 or M22.
As you stated in an earlier post, there is a P-code on the side of the muncie 4-speed in my car.
It is: P8T18
If I understand it correctly that means it was built on December 18th,
1967 , for a 1968 car.
Still not sure if it is a M20, M21 or M22.
#10
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That's correct. Pulling the side cover and looking at the helix angle of the gears is the sure-fire way to tell, but it's highly unlikely that it's an M22. If the rpm drop from 3-4 is the same as it is from 1-2 and 2-3, it's an M21; if the rpm drop from 3-4 is much greater than it is from 1-2 and 2-3, it's an M20.