differential year?
Thread Starter
Burning Brakes
Joined: Dec 2003
Posts: 1,150
Likes: 154
differential year?
I just had the diff replaced in my vette,as I'm tired of driving it with the 4.10's so the 3.55's are back in.When I checked out the #'s on the 4.10's I can't decipher the #.s correctly,I put that in years ago so it's not the original rear.The stamped #'s are, AC W 356 E 1. The parts book says AC is 4.10 gears W ,Warren 356 ? and E 1, The parts book says 4 numbers,date of mfg and E 1?The parts book says 71 vette or 72 to 75 for that rear. I don't understand the 3 #'s or the E 1.I would just like to know what year the rear is from so when I sell it I can tell a buyer what it is. Thanks in advance,Mike
Race Director
Joined: Oct 2000
Posts: 12,678
Likes: 3,129
From: Shamong, NJ
"AC" = 4.11 (not 4.10, but I'm taking your word on AC, since I'm traveling and don't have access to any of my reference material)
"W" = Warren MI assembly plant
"356" = Is the Julian date the rear was assembled, the 356th day of the year (because of leap years you need the year to know exactly what day was 356)
"E" = Is Eaton, the maker of the Posi unit and gear set
"1" = Is the first shift
To know what year the rear is you'll need to locate the casting date on the rear. It will be on the side and include a letter for the month, one or two numbers for the day and a single number for the year. The date is raised because it's cast into the rear, not depressed like the stamped info. A rear marked C 19 4 would have been cast on March (C) 19th (19) 1964 or 1974 (4).
"W" = Warren MI assembly plant
"356" = Is the Julian date the rear was assembled, the 356th day of the year (because of leap years you need the year to know exactly what day was 356)
"E" = Is Eaton, the maker of the Posi unit and gear set
"1" = Is the first shift
To know what year the rear is you'll need to locate the casting date on the rear. It will be on the side and include a letter for the month, one or two numbers for the day and a single number for the year. The date is raised because it's cast into the rear, not depressed like the stamped info. A rear marked C 19 4 would have been cast on March (C) 19th (19) 1964 or 1974 (4).
