Editing General Motors transmissions

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==Preamble==
The history of the Hydramatic transmission began back in 1932, when it was introduced by Cadillac as the "shiftless transmission". For more historical information, see [http://en.wikipedia.org/wiki/Hydramatic Hydramatic transmission at Wikipedia]. The scope of this article is mainly centered around the transmissions of the 60's to present date. However, if there is interest in prior years it can certainly be included.

This article will concern itself with the different types of transmissions used by General Motors, and their physical and mechanical properties. 

First, a transmission is a way of applying torque from an engine through a differential to a wheel, causing  forward (or reverse) motion of a standing body.

==Types of transmissions==

==Standard ==

==Three speed==

[[Image:64_Nova_3_sp.jpg‎]]
[[Image:64_Nova_3_sp_number.jpg‎]]
[[Image:64_Nova_3_sp._shift_levers.jpg‎]]

From a 1964 Nova 342 Saginaw.

==Four speed==
Manual Transmission Identification & Description 
 
[[Image:Muncie_M20_4_speed.jpg‎|Muncie]]
[[Image:Saginaw2.jpg|Saginaw‎]]
[[Image:Borgwarner.jpg‎|Borg Warner]]

The Muncie reverse lever is in the extension housing, and the cover has 7 bolts. While looking at the cover, 3rd/4th gear lever is on the left. 1st/2nd gear lever is on the right.

The Saginaw reverse shift lever is on the cover, and the cover has 7 bolts.

The Borg Warner has a 9 bolt cover.

===Borg-Warner===

===Muncie===
See: [http://www.yearone.com/updatedsinglepages/Id_info/muncie.asp Muncie 4-Speed Identification], [http://www.nastyz28.com/2gcog/trans.html Camaro Transmission Information and Restoration], and [http://www.yearone.com/yodnn/tech/VehicleInfoDecoding/GMMuncie4SpeedDecoding/tabid/349/Default.aspx GM Muncie 4-Speed Decoding].

===Saginaw===

==Five speed==


==Six speed manual==
GM used three basic 6 speed manuals over the years: the ZF S6-40, the Borg Warner/Tremec T56, and the New Process/New Venture NV5600 in trucks.

===German ZF S6-40===
Starting with the 1988-96 Y-body (Corvette), a German ZF 6-speed was used, designated S6-40.  It was stout and reliable, but its limited use and short production run didn't support wide aftermarket solutions.  In fact GM didn't even stock service parts for the transmissions, instead opting to provide remanufactured units instead of repairing them.  Although it ended up costing GM less in the long run, it was a concept not warmly received by the public.  Early models were rated for 400 ft-lbs, and later models were rated to 450 ft-lbs.  ZF 6-speed ratios are as follows:

Reverse - 2.50
/First - 2.68
/Second - 1.80
/Third - 1.29
/Fourth - 1.00
/Fifth - 0.75
/Sixth - 0.50

[http://i162.photobucket.com/albums/t264/curtis73/explodedZF.jpg Exploded view of an S6-40 transmission].


===Borg Warner/Tremec T56===
Starting with the 1992/1993 F-body (Camaro, Firebird, Trans Am) the six speed was a Borg Warner-designed, Tremec-built T56 transmission. Although the basic design, case, and internal operation were the same, three different ratio gear  sets were available in GM applications. In 1993, F-body cars were equipped with two optional rear axle ratios; 2.73 and 3.23. Beginning in 1994, all T56 cars used the same ratio gear set regardless of rear axle ratio. 1992-1993 T56s with the lower gear sets had a slightly lower torque capacity in the 350 lb-ft range while 1994-later (high) gear sets reduced the side loads on the case and were rated to 450 lb-ft. T56 use continued like this until 1997 when it also started being used in the Y-body (Corvette) as a rear-mounted transaxle, and continued on in F-bodies behind the LS1 until the end of their production.

Of note is the fact that all T56 transmissions share an interchangeable main case; even those found in Holdens, Fords, Vipers, and Aston Martins. What differs is the front adapter plate, tail shaft housing, shifter, and input/output shafts. Internally, there were some interchangeable differences, like the type of shift forks and syncronizers used, but for the most part, all T56s are built on the same stout center section. Gear ratios are as follows:

====1993 F-body, 2.73:1 axle====
Reverse - 3.28
/First - 3.36
/Second - 2.07
/Third - 1.35
/Fourth - 1.00
/Fifth - 0.80
/Sixth - 0.62


====1993 F-body, 3.23:1 axle====
Reverse - 3.28
/First - 2.97
/Second - 2.07
/Third - 1.43
/Fourth - 1.00
/Fifth - 0.80
/Sixth - 0.62


====1994-current GM production====
(edit when they quit using it)
Reverse - 2.90
/First - 2.66
/Second - 1.78
/Third - 1.30
/Fourth - 1.00
/Fifth - 0.74
/Sixth - 0.50


[[http://i162.photobucket.com/albums/t264/curtis73/tremect56.jpg A photo of a Tremec T56]]. Note the multiple options for shifter mounting positions.

===NV5600===
Designed by New Venture, this stout truck six speed is up to the task of living behind engines like the Duramax and 8100 Vortec. For obvious reasons it has little application in hot rods due to its huge size, excessive weight, and truck-like gear ratios.

[http://i162.photobucket.com/albums/t264/curtis73/IMG_1564-copy.jpg A photo of an NV5600]

==Overdrive units==
See this pictorial article for information on rebuilding these overdrive units: http://www.classictruckshop.com/clubs/earlyburbs/projects/t85n/rebuild.htm.

==Automatic transmissions==
*'''General Identification'''

Bell housing patterns

Photo of the Buick, Oldsmobile, Cadillac, Pontiac bolt pattern bell housing. Notice the valley between bolt holes at the top of the bell housing.
 

[[image:BOP_bell_pattern.jpg]]


Photo of the common Chevrolet bolt pattern bell housing.  The pattern has a peak between the bolt holes at the top of the bell housing.

[[image:Chevy_bell_pattern.jpg]]



Transmission Identification By Pan Shape

[[Image:Pan_id.jpg‎ ]]


{| style="background:yellow"
! Image Number !! Transmission(s) !! Pan Bolts 
|-
! 1
| Aluminum Powerglide 
| align = "center" | 14
|-
! 2 
| TH200 (Metric), TH200C (Metric)
| align = "center" | 11
|-
! 3 
| TH250, TH250C, TH350, TH350C, TH375B
| align = "center" | 13
|-
! 4 
| TH375C, TH400, TH475, 3L80, 3L80HD
| align = "center" | 13
|-
! 5 
| TH200-4R 
| align = "center" | 16
|-
! 6 
| TH700-4R, 4L60, 4L60E 
| align = "center" | 16
|-
! 7 
| 4L80E
| align = "center" | 17
|}


Transmission Dimensions

[[Image:Transmission_dimensions.jpg‎ ]]
 

Typical Application Information

[[Image:Transmission_guidelines.jpg‎]]

== Two speed automatic==

===Powerglide===

The Powerglide transmission was used in Chevrolet vehicles, even Corvettes.  The 2 speed automatic used in Buick , Olds and Pontiac vehicles was known as the Super Turbine 300 or ST-300.  The ST-300 transmission was similar to the Powerglide but few parts were directly interchangeable.  

The ST-300 was also produced with a variable pitch torque converter. This converter could change stall RPM with an electric solenoid inside the transmission that was activated by a switch usually mounted on the throttle linkage.

==Three speed automatic==

===THM-350, THM-350C, THM-375B===
the T-350 trans was built in 5 different lengths. Two were 4x4 applications. Tail housing lengths of the two wheel drive  were 6 inch , 9 inch and 12 inches.  The 12 inch length is not very common. It was used mostly in station wagons of Buick - Oldsmobile brands

===TH-400(3L80), THM-375C, THM-475(3L80HD)===
1987-up 3L80HD is the HD version of the TH400 found in light trucks.  It has 27 spline output shaft and is 34.5" long over all in 4x2 version. common tag code on these is LJA.  Found cast on the bell housing in medium size letters is 'HD'.  1964-1990 are the years of the TH400 transmissions.  1987 was the year the transmissions were renamed to the new alpha-numeric values.

==Four speed automatic==

===TH-200-4R===

This 200-4r transmission is the same length as a 6 inch tail housing T-350 transmission.

The 200-4r requires a TV cable hook up at the EFI - carb with the correct geometry for correct operation.

===TH-700R4(4L60)===

===4L60E===
4l60E is an electronic shifted and pressure controlled version of the 700-r4 / 4L60 transmission.

===4L80E===

==Five speed==

==Comparisons==


[[Category:Transmission]]