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Anomaly? I thought the tapered fill plug began with the 65 model year. I just cleaned one that is cast date on the cover in March 64, assembly date May 64 that has the tapered pipe plug. When did the straight thread plug with the round metal posi flag get replaced by the tapered plug with the plastic posi flag?
I always thought it changed in the 1965 M/Y, is the cover part # 303?
Bingo! From the garage to the house, my memory shuffled from fact. Housing is 375 and dates are on diff housing. Diff is assembled 5-64, cast 3-64, but cover is later with tapered plug. The other diff is a 303 cover, but cracked from a long spring bolt and now I need 2 303 covers.
Well, not so fast . Searched my stash and found a 303 (maybe, it’s rusty) with straight threads. While removing, realized my first post is right, still. This cover is a 375 casting with plastic vent and cast date is Feb 21, 64. It came to me on the diff with a March cast date and May assembly date, all 64. Seems strange.
In my stash, I found another cover, no cast date, 303 casting with a tapered thread plug! . It has the plastic vent, GM 8 mold #.
I don't recall cover date codes on the 63-4's. Seem to recall that might have started in 67?
All the 63-4 covers I worked on had steel vents, 1"-20 threads I believe. Posi tags were round steel, bare with various notches for ratio in 63 and wording in 64.
I never recall seeing one with the 3/4 npt plug until 1965, when they went to the red plastic posi tags and plastic vents.
I don't recall cover date codes on the 63-4's. Seem to recall that might have started in 67?
All the 63-4 covers I worked on had steel vents, 1"-20 threads I believe. Posi tags were round steel, bare with various notches for ratio in 63 and wording in 64.
I never recall seeing one with the 3/4 npt plug until 1965, when they went to the red plastic posi tags and plastic vents.
My thoughts are the same. That’s why these 2 seem odd. Don’t fit the “rule”. Guess the dated one (B214) could be 74. Had not considered that.
well, I was curious too as I have never seen what you described. I have to admit though I don't always pay attention to casting numbers, I am looking to see if there is a problem with the part.
I pulled a 64 diff from my file showing the original cover. No date code, machine plug, metal vent. Now there something I did forget about these covers- look at the bottom 2 holes, the casting has a boss- a raised pad so to speak. The top 2 holes don't.
I had noticed those bumps on some / all as well. Also noticed that the casting changed on the 375 where the top two were not drilled through and tapped as on 303. Looks like more metal added there.
64 Differential
. Searched my stash and found a 303 (maybe, it’s rusty) with straight threads. While removing, realized my first post is right, still. This cover is a 375 casting with plastic vent and cast date is Feb 21, 64. It came to me on the diff with a March cast date and May assembly date, all 64. Seems strange.
. It has the plastic vent, GM 8 mold #.
?
