Ford Toploader transmission

Toploader Transmission
Overview
Type	3 or 4-speed manual
Manufacturer	Ford Motor Company
Also called	Ford Design 4-Speed 3.03 (3-Speed) Top Loader
Production	1964–1973
Chronology
Predecessor	Borg-Warner T-10 Dagenham 4-speed

A Toploader transmission is a manually shifted gearbox built in both three-speed and four-speed configurations, introduced in 1963 by the Ford Motor Company to replace the BorgWarner T-10. Officially designated as the 3.03 three speed or Ford design four speed, it was used in most Fords and Mercurys from 1964 until 1973, as well as in many 1960's GM musclecars, and some foreign models.

The Toploader name came from the fact that the access plate to the inner workings was located on the top of the main case, as opposed to side access on most comparable gearboxes. The designation 3.03 is the centerline distance between countershaft and mainshaft. The transmissions can be distinguished by the number of top plate fasteners: the four speed has ten, while the 3.03 has nine.

In the early 1970s, production transferred to Mexico, and this transmission became the Tremec T-170, HEH, or RUG depending on the year(s) of production. The Tremec T150 transmission is a Toploader with the addition of a cast top cover and a floor ("cane") shifter.

Design

Both the three and four speed top loader gearboxes were designed to function in constant mesh, due to synchronizer sleeves being used instead of sliding gears, and be fully synchronized, with the exception of reverse. Forward gears are helical-type, while reverse gear and the exterior of the first and second synchronizers sleeve are spur-type gears.

Applications

Toploader 4-speed w/ Hurst shifter

Renowned for its high-performance strength and durability, the Toploader (particularly the four-speed) was used extensively in racing, and equipped many "A-list" cars such as the Mustang, Talladega, AC Cobra, AC Frua and Sunbeam Tiger. Overall, the Toploader was used in 133 different models, including the Ford Fairlane, Falcon, Galaxie, Ranchero, Torino, Bronco and the Mercury Comet, Caliente, Cyclone, Cougar and Marauder.

Sourcing parts from competitors was common practice in those days. GM used the 3.03 Toploader in its 1960s Oldsmobile, Buick and Pontiac musclecars, but marketed it as the Dearborn HD 3-speed (even with FOMOCO still cast into the case).

Specifications

Shafts in a 3-speed manual automobile gearbox c. 1935

Toploaders were designed for two specific applications: small blocks like the Ford Windsor engine, and big blocks like the Ford FE engine and Ford 385 engine series. Some big blocks required a larger "input shaft" to withstand the torque.

The Toploader is constructed of a main case and a tailhousing. The 10" long case encloses the gears, input shaft, and counter-shaft. The tailhousing encloses the speedometer gear and output shaft, and is cast with mounting bosses for the shifter.

Shifter position varied, so Tailhousings measure 14", 15 1⁄2" or 17", depending on the application. Generally, Falcons and Comets had shifters mounted forward along the housing, Mustangs rearward, and Fairlanes and full size Fords in-between.

Toploader 4 speed

Application	Engine used (cid)	Toploader Length	Input shaft OD	Splines, input	Splines, output
Cougar	289, 302, 351	26"	1 1⁄16"	10	28
Falcon, Comet	170, 200, 260, 289	26"	1 1⁄16"	10	28
Fairlane 1964-65	170, 200, 260, 289	25 1⁄2"	1 1⁄16"	10	28
Fairlane 1967-68	200, 289, 390	26"	1 1⁄16"	10	28
Maverick	200, 250, 302	26"	1 1⁄16"	10	28
Mustang 1964-73	170, 200, 289	26"	1 1⁄16"	10	28
Ranchero 1967-68	200, 289, 390	26"	1 1⁄16"	10	28
Tiger, TVR	260, 289	27 1⁄2"	1 1⁄16"	10	28
Fords, Mercurys	200, 289, 390	29"	1 1⁄16"	10	28
Ranchero 1969 up	302,351C, 428, 429	29"	1 3⁄8"	10	31
Fords, Mercurys	428, 429, Boss	29"	1 3⁄8"	10	31
Mustang 1968 up	427, 428, Boss	26"	1 3⁄8"	10	31
Cobra 1965 up	427, 428

Note: 1964 and early 1965 Toploaders came with 25-spline output shafts which subsequently proved to be defective and were quickly replaced.

Gear Ratios

Toploader 3 speed - Close

	1st	2nd	3rd
Ratio	2.42	1.61	1.00

Toploader 3 speed - Wide

	1st	2nd	3rd
Ratio	2.99	1.75	1.00

Toploader 4 speed - Close

	1st	2nd	3rd	4th
Ratio	2.32	1.69	1.29	1.00
Tooth Count	32	28	25	23
Counter Gear Tooth Count	15	18	21	25

Toploader 4 speed - Wide

	1st	2nd	3rd	4th
Ratio	2.78	1.93	1.36	1.00
Tooth Count	32	31	25	23
Counter Gear Tooth Count	15	21	24	30

Note: Gear ratio is determined by tooth count on second gear. Close ratio has 28 teeth, wide has 31.

External links

• Website on the Toploader 4-speeds
• "Mustang Monthly" - How to Rebuild a Toploader Four-Speed
• http://www.tbtrans.com/ford_toploader_4_speed_trans.htm