Rear Axle Section Links
none
Rear Axle Gears and Driveshaft
1964-67 Chevelle rear ends were manufactured by the Chevrolet Gear and Axle Division and were the same width. Measuring two different 10-bolt rear ends, I found the following:
Rear end #1 not in car. From backing plate-to-backing plate, 53.3125 inches. Wheel mounting surface-to-wheel mounting surface (outside brake drum-to-brake drum) measures 59.875 inches. The tape measurement photo below shows 60.1875 inches but there is the extra length of the tape going up/down the brake drum. If you measure close to 60 inches and not as much as 62 inches, you can be assured the rear end is from a 1967.
Rear end #2 in car. From backing plate-to-backing plate, 53.250
inches. Rear wheels were not removed to measure the outside drum-to-drum because
the inside measurements are within 1/16-inch and I didn't feel
the need to jack up the car and remove the wheels.
Note: Other sources put the total width at 60.5 inches,
so measure carefully. I did find that by using a steel tape and 'bending' it over
the top of the brake drums I came up with 60.1875 inches; see
photos below.
1968-72 Chevelle rear end housings are about 2 inches wider overall, but again, be careful what you measure to/from and how much slack is in your tape.
The 10 bolt Chevelle rear end has the 8.2" ring gear from 1964 to early 1972. It wasn't until late 1972 that the 10 bolt 8.5" ring gear was used in Chevelles.
Rear spring mounting pads differed in that 1964-66 rear ends used a flat pad with a hole drilled in the center. 1967 rear spring mounting pads had a raised 'hat' design and tapered coil springs.
Note lower spring retention plate on the 1966 rear end above as opposed to 1967
rear end below with tapered lower pigtail and 'top hat' design lower spring perch.
Backing plate-to-backing plate - 53.3125 +/- 0.165 (1/16")
Outside drum-to-outside drum - 60.1875" (60 3/16 inches).
Quote from the Chevrolet P&A Catalog: "1965 to 1969 production numbers are stamped on the bottom left or right axle tube either adjacent to the carrier housing or about 8"-10" inboard from the backing plate - usually on the passenger side."
Although this is from a 1967 Chevelle as noted by the spring lower perch, the
focus is the location of the identification information.
Close-up of above 1967 rear axle housing. CB 1012 W decodes to CB=3.36:1, 1012=Month
[Oct] and Date [12], W=Warren, MI.
Decoding the stamped information is as follows:
* The first two letters indicate the gear set ratio that was installed. See table
below to decipher these first two letters.
* The assembly date of the axle assembly is shown with 4 digits; the first two
being the month (01..12) and the second two being the date (01..31)
* The last letter is the plant of assembly letter code
* If the gear set is a Positraction unit, normally the original equipment supplier
letter code is stamped below the above 7-character codes.
Plant Codes:
* G=Detroit Gear & Axle
* B=Buffalo, NY
* W=Warren, MI.
* K = McKinnon Industries
Positraction Codes (Original Equipment Suppliers to GM)
* D=Dana Positraction
* E=Eaton Positraction
A typical rear axle code stamping will look like one of those shown below.
CW 0923 decodes to CW=3.31:1 Positraction, 0923=September 23. (Plant not captured
in photo)
KF 1014 B decodes to KF=3.55:1 w/metallic brakes, 1014=October 14, B=Buffalo, NY
CF 1015 E decodes to CF=3.31:1 Positraction, 1015=October 15, B=Buffalo, NY,
E=Eaton (original equipment manufacturer for GM Positraction).
CW 1112 B decodes to CW=3.31:1 Positraction, 1112=November 12, B=Buffalo, NY
CX 0104 B decodes to CX=3.07:1, 0104=January 4, B=Buffalo, NY
I purposely cropped this one a little wide to show how road grime can accumulate
on the rear axle housing.
KM 0114 B E decodes to KM=4.56:1 Positraction, 0114=January 14, B=Buffalo, NY, N.Y.
E=Eaton (original equipment manufacturer for GM Positraction).
CF 1127 E decodes to CF=3.31:1 Positraction, 1127=November 27, E=Eaton (original
equipment manufacturer for GM Positraction). (Plant not captured in
photo)
CI 0503 E decodes to CI=3.73:1 Positraction, 0503=May 3, E=Eaton (original equipment
manufacturer for GM Positraction). (Plant not captured in photo)
CF 0509 B E decodes to CF=3.31:1 Positraction, 0509=May 9, B=Buffalo, E=Eaton (original
equipment manufacturer for GM Positraction).
CX 0727 B decodes to CX=3.07:1, 0727=July 27, B=Buffalo, NY
| Identification Code | Ratio |
| CA (10-bolt) | 3.08:1 |
| CB (10-bolt) | 3.36:1 |
| CC (12-bolt) | 3.73:1 |
| CD (12-bolt) | Positraction 3.07:1 |
| CE (10-bolt) | Positraction 3.08:1 |
| CF (12-bolt) | Positraction 3.31:1 |
| CG (10-bolt) | Positraction 3.36:1 |
| CH (10-bolt) | w/metallic brakes 3.70:1 |
| CI (12-bolt) | Positraction 3.73:1 |
| CJ (12-bolt) | w/metallic brakes 3.07:1 |
| CK (12-bolt) | Positraction w/metallic brakes 3.07:1 |
| CL (10-bolt) | w/metallic brakes 3.08:1 |
| CM (10-bolt) | Positraction w/metallic brakes 3.08:1 |
| CN (12-bolt) | w/metallic brakes 3.31:1 |
| CO (12-bolt) | Positraction w/metallic brakes 3.31:1 |
| CP (10-bolt) | w/metallic brakes 3.36:1 |
| CQ (10-bolt) | Positraction w/metallic brakes 3.36:1 |
| CR (10-bolt) | Positraction 3.70:1 |
| CS (10-bolt) | Positraction w/metallic brakes 3.70:1 |
| CT (12-bolt) | w/metallic brakes 3.73:1 |
| CU (12-bolt) | Positraction w/metallic brakes 3.73:1 |
| CV (10-bolt) | Overdrive 3.70:1 |
| CW (12-bolt) | 3.31:1 |
| CX (12-bolt) | 3.07:1 |
| KC (12-bolt) | w/metallic brakes 2.73:1 |
| KD (12-bolt) | Positraction 2.73:1 |
| KE (12-bolt) | Positraction w/metallic brakes 2.73:1 |
| KF (12-bolt) | w/metallic brakes 3.55:1 |
| KG (12-bolt) | Positraction w/metallic brakes 3.55:1 |
| KH (12-bolt) | Positraction 3.55:1 |
| KI (12-bolt) | "396" w/Powerglide 2.56:1 |
| KJ (12-bolt) | 3.55:1 |
| KK (12-bolt) | Positraction 4.10:1 |
| KL (12-bolt) | Positraction w/metallic brakes 4.10:1 |
| KM (12-bolt) | Positraction 4.56:1 |
| KN (12-bolt) | Positraction w/metallic brakes 4.56:1 |
| KO (12-bolt) | Positraction 4.88:1 |
| KP (12-bolt) | Positraction w/metallic brakes 4.88:1 |
Note some differences listed for GM of Canada Chevelles & Beaumonts.
Codes KC, KD, KE, and KI are not listed. Codes KF & KH have different
types and brake linings.
The date code on a rear end housing is simple to decode. It includes the month, day and year such as I245. This decodes to September 24, 1965. Month codes are A through L for January through December.
| A - January | D - April | G - July | J - October |
| B - February | E - May | H - August | K - November |
| C - March | F - June | I - September | L - December |
I245 casting date of September 24, 1965
J65 casting date of October 6, 1965
D146 casting date of April 14, 1066
Rear Gear Assembly - Group 5.529
GM did not sell the ring or pinion gear separately but rather as a unit. Part
numbers below indicate the unit number with the ring gear part number followed
by the pinion gear part number, again, not sold separately.
12-bolt gear ratios
| Chevrolet Part Number | Ratio Ring/Pinion |
Fits |
| 3961404 (39/8T) (3862528/3862516) |
4.88:1 - 39/8 | 65-69 All |
| 3961405 (43/13T) (3862689/3862693) |
3.31:1 - 43/13 | 65-70 All, 71 All exc. Pass |
| 3961406 (39/11T) (3853010/3853008) |
3.55:1 - 39/11 | 65-69 Pass, 66-68 Chevy, Chevelle, Camaro, 69 Chevelle, 70 All |
| 3961407 (43/14T) (3863691/3853003) |
3.07:1 - 43/14 | 65-70 All and 71 Nova |
| 3961408 (41/11T) (3862525/3862513) |
3.73:1 - 41/11 | 65-69 All and 70 Camaro |
| 3961409 (41/10T) (3862526/3862514) |
4.10:1 - 41/10 | 65-69 All, 70 Chevelle, Camaro, 71 Malibu (Spt Cpe, Conv, El Camino [Custom] 8-cyl) |
| 3961410 (41/9T) (3862527/3862515) |
4.56:1 - 41/9 | 65-69 All |
| 3961434 (41/16T) (3871038/3871041) |
2.56:1- 41/16 | 67 Chevelle w/A.I.R., 68-70 Camaro, 69 Chevy, 68-70 Pass |
| 3961435 (41/15T) (3869788/3869785) |
2.73:1 - 41/15 | 65-70 All, 71 Chevelle |
10-bolt gear ratios
| Chevrolet Part Number | Ratio Ring/Pinion |
Fits |
| 3961412 (37/11T) (3880044/3790628) |
3.36:1 - 37/11 | 64-68 Pass, 69-70 All, 71 Chevelle, Nova |
| 3961413 (37/12T) (3880043/3790629) |
3.08:1 - 37/12 | 64-70 All, 71 All exc. Pass |
| 3961414 (37/10T) (3880048/3849722) |
3.70:1 - 37/10 | 64-68 Chevelle, 65-68 All |
| 3961411 (39/11T) (3880046/3790627) |
3.55:1 - 39/11 | 64-69 All |
| 3961425 (41/15T) (3910818/3910823) |
2.73:1 - 41/15 | 67-70 Chevy, Chevelle, Camaro, 68-70 Pass, 71 Chevelle, Nova |
| 3961426 (41/16T) (3917184/3917185) |
2.56:1 - 41/16 | 68-71 Chevelle, 68-70 Chevy/Camaro, 68-70 Pass., 71 Nova |
Ring gear of 3.07:1 ratio 12-bolt - Chevrolet lists the ring gear as part #3863691.
The original tag reads, "USE POSITRACTION DIFF. LUBRICANT ONLY" while replacement tags like those shown reads, "USE LIMITED SLIP DIFF. LUBRICANT ONLY."
Driveshaft - Group 5.544
| Part Number | Reference | Fitment |
| 3898244 | P&A Catalog | 67-67 Chevelle, 68 Chevelle (4-dr) El Camino |
| Rear Flange for center housing - Group 5.545 | ||
| 3878972 | P&A Catalog | All w/12-bolt cover |
| 3997957 | P&A Catalog | All w/10-bolt cover |
| 1.
3868910 Axle Asm 1. 3868912 Wagons & Pickup Delivery 1. 3868930 13817-67 |
2. 102634 Nut(1) | 3. 103320 L. Washer | 4. 1358938 "U"-bolt |
| 5.
3868653 Prop. Shaft Asm 5. 3881652 13817-67 |
6. 358501 Nut(2) | ||
|
(1) 12-16 lbs. ft. (2) 55-75 lbs. ft. |
