DOES anyone have the Factory book on the carrier breaks in this 9 3/8" Buick rear? Trying to help a customer with a carrier...I just want to be sure it will fit or if we need to set them up with a spacer too. THANK YOU all. Jim
I’d like to know as well. One data point I do know is the 3.42 and 3.91 (65 ) work on the same carrier. I’ve got some 3.23 and 3.08 units here that I can look at and compare.
I looked at the parts book and it LOOKS like 2.41-2.56/2.93-3.23/3.42-4.11 but there is a bulletin out there somewhere that gives more detail - Buick 66-163
Yah something is not right...WE keep getting all this different info. WE NEED someone with a definitive answer. It would nbe nice if we had CARRIERS to measure with casting numbers ... I have the 32103 and 32120 as the same offset of 1 3/4" ring gear offset. There is a 2" offset also . I just KNOW ABSOLUTELY the 32120 and the 32103 are 2.79 ratio (14 -39 tooth count) For sure. If anyone else has info ...absolute. Please let me know. I have 32086 as same bearing 1 3/4" offset 32121 as 2" offset 3.42 and up ratios 32085 as 2" offset 3.42 and up as same carrier bearing left and right. 32087 unknown maybes 32102 unknown maybe These are all the casting POSI numbers I have that i know of... BUT I want to confirm any I can as to what they are and offsets. IT really appears there are only 2 carrier offsets so far 1 3/4" and 2" IF you find anything else I would really like to know. BOOK ...ok BUT Physical is really the best. Thanks, Jim Mitschke JD Race
Generally, 3.23 is the break.. here is the complete parts book information: Have to watch out mixing terminology.. in the parts book, the piece that holds the clutches and ring gear is called the "Differential Case", and the "Carrier" is actually the cast iron housing that the case fits into. The parts book lists the PN of the specific case, and then in 1966, the casting number of the carrier where you may find that case. Although it should be noted that you will find both Positive Traction (P.T), and what they refer to as "less P.T." cases in these carrier numbers.. It calls out Buick Dealer Service Information Bulletin No 66-163 to field Identify 1st and 2nd type differential cases. In 66 1386390- Case, P.T. 1st design 2.78-3.07-3.23 ratio- diff carrier casting 1374836 for the 6000-8000 series, the Riv's (9000 series) had carrier casting number 1374715 1382254- Case P.T. 2nd design 278-3.07-3.23 ratio- diff carrier casting 1380708 for the 6000-8000 series, 9000 series 1380709 1376391- Case P.T. 1st Design- 3.42-3.91 ratio- diff carrier casting number 6000-8000 1374836, 9000 series 1374715 1380714- Case P.T. 2nd Design- 3.42-3.91 Ratio, diff carrier casting number 6000-8000 1380708, 9000 series 1380709 67 1382254- case P.T. 6000-9000 series - 2.56-2.78-3.07 ratio 1380714- Case P.Tl 6000-9000 series - 3.42-3.91 68-70 Strangely enough, this version of the parts book, does not call out a specific P.T. case for these years, although it does call out a "less P.T." (a.k.a. open) case.... one must assume the 67 numbers carried over.. and the ratio breaks are the same for the open cases. In next design 71 rear end: 231055- Case, P.T. 6000-9000 series 2.73-2.93 ratio 231056 Case, P.T, 6000-9000 series 3.42 ratio JW
Sooo it appears there are ONLY 2 series High and low... Which in my case is the INFO I am getting from another person that says the 3.07 ratio were on some of what I have listed as 2 series.
That is weird as the same era of 8.25" 10 bolt Mid size car A-Body Buick has 4 different break. 2.56 / 2/73-2.93 / 3.23 - 3.42/ 3.64 - 5.00
9 3/8" series is: 2.56 2.78 3.07 3.23 3.42 3.64 3.73 --- and beyond. Wow. let me know if this is correct BOOK WORMS. I appreciate you.
In a full size 9 3/8 rear they had 4.45 or even 3.91 just seems awfully steep for the type of car this is ...A BUICK FULL size car.
I ran the 3.91 for years in my high 11 sec street strip 69 Wildcat. Started breaking cross pins and Spyder gears. Fabbed up a 9 inch Ford with all the good stuff. The car now runs in the 10s I put the 3.91 rear in my low 12 second 70 Wildcat stock appearing. There's a few sets floating around out there. Kenne Bell used to sell the 4.45s Jim Bell said they were ambulance gears. I think you needed a spacer for the installation.
