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Automatic Transmission

700R4 “Bad Boy” Description 


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The 700R4 "Bad Boy" is generally used in vehicle applications where the vehicle will be used in beyond-stock 4x4, heavy duty or performance applications where overdrive capability is desired (30% O/D). The 3.06 1st gear sought after for 4WD applications The unit is well suited to aftermarket conversion applications as no external computer is required. We build these transmissions for applications behind GM, AMC, Jeep, and Ford engines, and have adapters available for almost all common transfer cases including Toyota units.

“Bad Boy” is a designation  High Impact adds to a custom built 700R4 automatic transmission to differentiate it from a stock replacement transmission. These transmissions are built for aftermarket conversions and applications where the demands placed upon the transmission far exceed anything General Motors ever built the 700R4 for.

There a number of standard upgrades included in all Bad boy units, such as an upgraded HD torque converter with furnace brazed turbine elements and HD lock up clutches, oversize sprags, upgraded pressure regulator and reverse boost valve, and internal modifications for improved oiling and shifting.

A Bad Boy is typically engineered and built for a specific application. Diesel applications require further pump upgrades. Racing applications require ability to handle hard shifts high RPMs as a matter of course. 4WD applications must operate reliably at crazy angles, and not slip, even at very low crawling RPMs. Towing applications must be able to withstand sustained high torque. 4WD and Towing both tend to exaggerate the heat loads. Shift firmness and shift points are calibrated to the application.

 Generally speaking, any High Impact  “Bad Boy” 700R4 transmission will withstand 450 ft-lbs of torque, 450 HP, 6000 RPM. It will then be further optimized for the specific application.

We also build “Bad Boy” extended versions capable of handling 600+ HP, 500+ ft-lbs/torque, 180MPH top speeds, full race high stall / launch desert racing and drag applications. Such transmissions are entirely custom, and are built and priced as such.

Lock-up vs. non-lock-up converter: 

If it is going to be used on the highway. use a lock-up converter. If it is competition-only, use a non lock up converter. Lock up will do you not good in racing, however a significant portion of your fuel savings on the highway is because of lock-up used with the OD. OD without lock-up tends to make a lot of heat in the torque converter. 

Our BadBoy 700R4 is available configured for computer controlled or  non-computer controlled applications. The non-computer control system will automatically lock up the converter whenever the trans goes into overdrive. Wiring and a switch can be added for full manual control of converter lockup in these BadBoy units.

Transmission Specifications:

Description: The General Motors 700R4 is an Automatic Overdrive transmission. At one point the name was changed to 4L60, but this is simply a later version of the same trans. It is available in two different bell housing bolt patterns: Chevrolet and Buick. It comes from the factory with a 27 spline output shaft. They are available in 2WD and 4WD versions. Note" The 4L60e is a different trans, is electronically controlled, and later units have different dimensions. 

It has a main case (Does not include tail housing or adapter) length of 23.375 inches.

Gear Ratios:

1st:= 3.06         2nd  =1.62       3rd =1.0        4th = 0.7

700R4 Conversions


Non-Computer applications

Our 700R4 bad boy is a popular conversion for persons wanting to retrofit an overdrive automatic into an older vehicle. It is one of two models that can be built in such a way as to require no computer whatsoever. (We also build a Ford AOD "BadBoy" for computer-free conversion)

Conversions in GM Vehicles

We carry conversion packages in GM vehicles from the Powerglide, Turbo 350 and Turbo 400 trans. We can also put together packages to convert from stick transmissions

Conversion in Jeeps

Our 700R4 "BadBoy" has also been a popular conversion  has also been a popular conversion in Jeep vehicles wanting an overdrive automatic. There is an overdrive automatic (AW4) used in Jeep vehicles, however it requires computer control which makes it much more difficult to retrofit into an existing vehicle. The 700R4 BadBoy will also allow you to hold the trans in 1st while the AW4 will not.

We have available packages, including adapters and linkages, etc, designed to retrofit a 700R4 into a Jeep Vehicle

Conversions in Fords and Dodge/Chrysler products

We have the adapters and can package systems to install this transmissions behind Ford 302-351 Windsor series engines and Chrysler Corp 318-360 small blocks

Crossmember and Driveshaft

When converting from a Turbo 350, the 700 is a couple inches longer. When converting from a Turbo 400, the 700 is a bit shorter. Compensating for this usually involves relocating the trans crossmember a little bit (in many cases, simply by drilling new holes in the frame rails) and having the drive shaft(s) length modified (by a driveshaft shop). 


In most cases, conversions use an aftermarket floor shifter to operate the 700R4. Units are made by B&M, Lokar, Genie and others. We carry and recommend the Lokar shifter for non competition applications. We use the Art Carr gated shifter for full competition uses.

Using a column shift: If you have a column 3 speed shifter, they generally can be rigged to shift the 700R4. The trans has it's shift position detents inside it, so by rigging the selector arm and final link of the shift linkage a bit, you can make it so park comes out at park, 1st comes out at 1st, OD comes out a bit left of "D" and 3rd comes out a bit to the right of "D". Works fine.


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Wiring Options For 700R4 "Bad Boy" Torque Converter

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