Second Generation Camaro Owners Group - Transmission Information and Restoration

The Second Generation Camaro came standard with a manual transmission. An Automatic transmission was optional on any Camaro from 1970 to 1981. The transmission usage was dependant upon which engine was being ordered. This page will describe general transmission information. You can find specific transmission usage under the "Power Teams" section in the yearly Camaro information.

These manual transmissions were used in the Camaro:
  • Saginaw 3-speed
  • Saginaw 4-speed
  • Muncie 4-Speed
  • Borg-Warner T-10
These automatic transmissions were used:
  • Powerglide (PG)
  • Turbo-Hydramatic 200 (TH200)
  • Turbo-Hydramatic 350 (TH350)
  • Turbo Hydramatic 400 (TH400)
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General Camaro Transmission Information

The 6 cylinder models came with Saginaw 3 speed transmissions. A 4 speed manual transmission was not offered with the 6 cylinder.

V8 engines came with either a 3 or 4 speed Saginaw or Muncie. The Muncie was typically used in high horsepower applications.

In January 1974 the muncie transmission was replaced by the Borg Warner T10.

1980 saw the TH200 used on the V6. 1981 saw the introduction of a lock up torque converter.

With the exception of the Saginaw transmission and the TH200, these transmissions tend to be overbuilt for the stock power capacity of the Camaro. In my opinion, the T10 is stronger than the M22 "rock-crusher" muncie. If I had to guess, I believe this transmission was introduced to eliminate the need to have 2 different close ratio transmissions available for the car, even while the power levels were slumping. The Powerglide is a common drag racing transmission. The TH350 will live behind big-block engines if built and maintained properly.

NO Second Generation Camaro recieved an Overdrive transmission. High gear on any transmission is direct drive. Swapping a modern overdrive transmission into the Camaro is a good way to improve your cars driveability. It will allow the car to accelerate better, cruise easier and achieve better gas milage. These swaps are discussed in detail on the clubs message board.

Most Camaros were built to accept a manual transmission even if being ordered with an automatic transmission. The clutch rod hole will be punched and covered with a plate and the subframe will be drilled & tapped for the Z bar bracket. This makes auto/manual swaps relatively easy. These swaps are discussed on the clubs message board.

Rebuilding these components are major projects in themselves and outside of the scope of this document. You can find additional information on these tasks here:

Detailing: The transmission case is natural aluminum. The crossmember is semi-gloss black.

Camaro Transmission Decoding Information:

All factory installed transmissions contain a "Source Code" along with a "partial VIN code" stamped on them. The source code identifies which facility built the part and on what day and may also contain a designation (or usage) code.
Example Transmission Code: P3E03B - (P = TYPE (Muncie), 3 = year (1973), E = Month, 03 = Day of Month, B = M21)
Month code: (NOTICE this is NOT in alphabetic order)
A = Jan, B = Feb, C = Mar, D = Apr, E = May, H = Jun, K = Jul, M = Aug, P = Sep, R = Oct, S = Nov, T = Dec

Location of source code (varies by year)
Powerglide: Right hand side of pan.
On the THM350, the VIN will be stamped on either the drivers side housing near the shifter, on the right side of the housing just above the pan, or on a boss behind the bellhousing flange on the passenger side of the transmission.
On the THM400 the VIN is stamped on a machined surface just above the pan on the drivers side. Identification tag is rivited to right side of case.
3 speed: Left side of maincase on machined pad below side cover.
4 speed (Iron): Left side of maincase on machined pad below side cover.
4 speed (aluminum): Right side of maincase stamped sideways in front of extension housing.

The partial vin code ties this component to a specific vehicle.
Example: 19N500001. - Chevrolet Division, 1979, Norwood Assembly Plant, unit #1 (this would be from a 1979 Camaro).

Camaro Manual Transmission Information

Manual Transmission Eyeballing

Muncie (left) Saginaw (center) Borg Warner (right)

To quickly finger what you have, notice in the above picture:
The muncie reverse lever is in the extention housing, and the cover has 7 bolts.
The Saginaw reverse shift lever is on the cover, and the cover has 7 bolts.
The Borg Warner has a 9 bolt cover.

Camaro Manual Transmission Component Casting #'s.
Type Years Main Case Extension Housing Side Cover
Saginaw 3-Spd 1970 - 1972 3925647 3873886 3952645
  1973 - 1975 3925647 326558 3952645
Saginaw 4-Spd (IRON) 1970 - 1972 3925656 3873886 3952647
  1973 - 1975 3925656 326558 3952647
Muncie 4-Spd (aluminum) 1970 3925661 3857584 3952648
  1971 - 1975 3925661 3978764 3952648
Borg Warner 1974 1304 065 903 13.04.066.901 13-04-097-901

Further Muncie identification
3 Muncie 4 speeds were offered. The M-20 wide ratio, the M-21 close ratio, and the "Extra heavy duty close ratio" M-22, also known as the "Rock Crusher". The M-22 was generally installed behind severely powerful (high torque) big-block engines. The M-22 is distinguished from an M-21 by the angle of the gear teeth. The M-22 has "straight cut" gears. Due to this, the box tends to be noiser (whines or howls almost like a blower, which is why it's called a "rock crusher") than other boxes. The M-21 has a higher pitch angle on its gear teeth.

The close ratio gearboxs generally came with 3.73+ gear ratio'ed cars. 3.55 geared and higher (numerically lower) cars used the wide ratio gearbox.

Due to the wide combination of id's, stampings, numbers, etc... varied and even GM couldn't keep track of what was what, it's best to ID your gearbox visually, taking what is stamped on the box FWIW. The best way to ID the transmission is to count teeth.

Muncie 4 speed spline, groove and tooth count characteristics.
Type/Year

Input Spline

Input Groove

Input Gear
Tooth Count

Cluster Gear
Tooth Count

Output Spline

Gear Ratio

M20: 1963 - 65 10 none 24 29-22-19-17 27 Note 1
M20: 1966 - 70 10 2 21 25-22-19-17 27 Note 2
M20: 1971 - 74 26 2 21 25-22-19-17 32 Note 2
M21: 1963 - 70 10 1 26 27-22-19-17 27 Note 3
M21: 1971 - 74 26 1 26 27-22-19-17 32 Note 3
M22: 1965 - 70 10 none 26 27-22-19-17 27 Note 3
M22: 1971 - 72 26 none 26 27-22-19-17 32 Note 3

Note 1: M-20 gear ratio: 1st 2.56:1, 2nd 1.91:1, 3rd 1.48:1, 4th direct
Note 2: M-20 gear ratio: 1st 2.52:1, 2nd 1.88:1, 3rd 1.46:1, 4th direct, Rev 2.59:1.
Note 3: M-21/22 gear ratio: 1st 2.20:1, 2nd 1.64:1, 3rd 1.28:1, 4th direct, Rev 2.27:1

Effective October 21, 1968, an additional letter was added to the plant prefix number to help identify the gear ratios in Muncie transmissions. The additional letter codes as follows:

Muncie 3 speed Manual   Muncie 4 speed manual transmissions
Suffix   1st gear ratio
A   3.03:1
B   2.42:1
 
Suffix   1st gear ratio
A   2.52:1 wide range
B   2.20:1 close range
C   2.20:1 Rock Crusher

Borg Warner Exploded view and parts
Borg Warner T10

Camaro Automatic Transmission Information

Power Glide
Used from 1970 to 1972. This is a 2 speed automatic. It was available on the 6 cylinder and 307 V8.
This transmission is strong, or at least can be made strong, and it's popular with people who drag race cars.
This transmission can be identified simply in that it only has 2 forward speeds and the transmission pan is square.

Turbo Hydramatic 350
Used throughout the Second Generation Camaros production run, this was the standard duty V8 automatic transmission. Prior to 1973 it was the optional transmission on the lower powered 350 engines. In 1973 it became the optional transmission on the 6 cylinder and 307 engines. In 1975 it became the only automatic transmission available up until 1981.

This transmission can be quickly identified by the shape of the pan - square with a notch cut out of a corner, and it has a cable kickdown.

Turbo Hydramatic 400
Used from 1970 to 1974 primarily on high horsepower 350's and big-block engines. Generally, a Super Sport or Z28 equipped with an automatic will be getting a TH400.

This transmission can be quickly identified by the shape of the pan - "not square" (looks like the state of Indiana), and it has an electrical kickdown switch.

The electrical kickdown (or lack thereof) is helpful in identifying wether some cars were SS's or Z28's. The kickdown connection has a hole punched into the firewall for the wire to pass through. Plus there should be an electrical switch mounted on the brake pedal bracket.

Usage Code (on tag rivited to case):
CK is for small block TH400
CY is for big block TH400.


Last updated: 10/20/2011
Author: MadMike Maciolek

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