November 2020 – Gearstar

Would you like to know how to swap a TH200 4R transmission into early muscle cars for easy overdrive? If that is a yes, let us show you how to go through the whole process. First off, it is worth noting that the TH200 4R transmission is worth the time and effort you will put into swapping it into that ride of your choice.

The reason lies in the ruggedness of this transmission, which can be compared to the 700R4. In line with that, a few modifications to the TH200 4R will see this transmission nicely fitted into almost all Chevy chassis. You will also be spending less to get this transmission since it is the least expensive overdrive automatic.

Advantages of Using a TH200 4R Transmission

There are several advantages of using the TH200 transmission to swap into a muscle car:

1. As Strong as the TH700-R4

The TH200 4R shows the same torque capacity and durability evident on the TH700-R4. And the TH700-R4 is a performance automatic overdrive that has earned a lot of attention.

2. Gear Ratio

The TH200 4R has a better first-gear ratio. Specifically, this transmission uses a 2.74:1 First-gear ratio, and in comparison to the TH350’s ratio, it is more profound. Nonetheless, it is less deep than the TH700-R4’s 3.06:1 ratio. Also, there is a less severe RPM drop of the TH200 4R’s engine between first and second gear, and as such, the car accelerates after the gear change. It may also interest you to know that overdrive ratios between the TH200 4R and the 700-R4 are almost similar. These ratios are 0.67 and 0.70, respectively.

3. Compatibility

The TH200 4R is also a suitable replacement for powerglide/TH350 transmissions. It has the same basic overall length as the powerglide or Turbo 350 automatics. In line with that, it uses a similar 27-spline slip-yoke as a powerglide or a TH350 transmission. You will also find standard flexplates on this transmission. Accordingly, here is how to swap the TH200 4R transmission into early muscle cars.

How to Swap TH200 4R Transmission into Early Muscle Cars

The TH200 4R can easily be identified from other transmissions, including the TH350 and TH400, thanks to its unique pan design. And when it comes to swapping this unit into muscle cars, you need to choose a well-used TH200 4R. With that in mind, here is what you need to begin:

1. Universal TV Cable and Bracket

You will need to purchase a throttle valve (TV) cable and two different cable brackets. The cable brackets will be used for the Holley or Carter/Quadrajet Carburetor. It is essential to get these dedicated brackets to ensure good positioning of the TV cable to the primary throttle shaft.

2. Throttle Valve (TV) Cable

We’ll like to emphasize the throttle valve (TV) cable, on which the TH200 4R relies on. This cable serves as a replacement for the vacuum modulator valve and the kick-down linkage. It is essential to install and connect this cable properly. The connection between the TV cable and the transmission is made on the passenger side using a small hook. On the other hand, you can run the Turbo 350 or a powerglide without the kick-down cable, unlike the overdrive transmissions like the TH200 4R and 700R4 that need the TV cable adequately connected and adjusted. The TV cable helps to baseload on throttle position, which makes it essential. Not adjusting the cable properly, the clutches may get damaged within a short time due to high load with low trans pressure.

3. TV Cable Adjustment

You may want to carry out a TV cable adjustment to ensure that the cable is tight with the carburetor at wide-open throttle (WOT). What this adjustment does is to create maximum transmission-line pressure at WOT. Nonetheless, harsh part-throttle upshifts may be created if the cable is too tight. As such, you can loosen the cable to reduce inline pressure to soften the harshness slightly. A dimension you should consider is the distance from the throttle shaft to the TV cable connection.

4. Torque Converter

Swapping to a TH200 4R requires that you select the right torque converter. You can opt for a modified converter that is smaller with a higher-stall and lockup-style converter. The latter differs from a stock torque converter that is heavy. There are torque converters that support 2,600-4,000 stalls, and these can lock up under cruise conditions. They are also ideal for hot street cars with a big cam and deep gears. It is entirely possible to interchange TH200 4R converters with some early 700-R4 transmissions. In contrast, you cannot interchange Turbo 350, 400, or powerglide converters with the TH200 4R. On the other hand, it is easy to tell apart lockup converters using the converter’s flat flexplate side.

5. Wiring Kit

There is a universal lockup wiring kit you can use to retrofit TH200 4R and 700R4 automatics. The aim of doing this is to engage the lockup converter in fourth gear and, at the same time, disengage the lockup under the acceleration of downshifting. Over and above that, the kit offers a manual override option, which is beneficial if you opt for a lockup torque converter.

The Bottom Line

The steps above will get you started with swapping a TH200 4R transmission into early muscle cars. You will be working with a durable and robust transmission that comes with other advantages. It will withstand the impact on the road while you race; hence, it is worth using this transmission in the first place. Now try these installation tips above to see how well they work for you.

The Ford 4R70W transmission history and evolution has been an interesting one. It began with more fuel-efficient cars, given the high gasoline cost to run these vehicles. There was also a low supply of fuel, which made it expensive to drive heavy automobiles, large-displacement carbureted V-8s, 2- and 3-speed straight-drive automatics, and other cars.

As such, car manufacturers, including Ford, had to include components that will make cars run longer but with less fuel. One such modification led to the Ford 4R70W transmission launch, an upgrade to the Ford AOD transmission. Here is all you need to know about the 4R70W’s history, evolution, and how it differs from the AOD transmission.

History of the Ford 4R70W Transmission

The 4R70W denotes:

- Four-speed
- Rear-wheel drive (RWD)
- 700ft-lbs (input torque in ft-lbs x 10)
- Wide-ratio

The history of the 4R70W transmission can be traced to Ford’s automatic overdrive (AOD). AOD was launched in 1980, and it was the first domestic automatic overdrive transmission targeted at providing fuel-efficiency. This transmission featured hydro-mechanicals and direct overdrive lockup to mitigate wasteful slippage. The AOD also featured Ravigneaux geartrain components that made it rugged. However, there was still a need for improvement since the AOD had durability problems, especially in its overdrive unit.

Accordingly, the AOD Electronic Control (AODE)/4R70W was launched in 1991 to tackle these problems. The AODE was also meant to provide a more cohesive functioning of the engine and transmission. It is worth noting that the name AODE was maintained between 1991 to 1992 before introducing the 4R70W (which is also an AODE) in 1993. The 4R70W was fitted behind the 4.6L dual overhead cam (DOHC) V-8 in the new Lincoln Mark VIII and some F-Series trucks launched in the same year.

Functions of the Ford 4R70W Transmission

The 4R70W is also an AODE transmission; as such, its features are like an AODE. Some of these features help to identify the transmission from an AOD, and they include:

1. Gear Ratios

- First: 2.84.1
- Second: 1.55:1
- Third: 1.00:1
- Overdrive: 0.70:1
- Reverse: 2.23:1

The 4R70W differs from the AODE in terms of gear ratios. This transmission has lower gear ratios in first and second gears, which brings about improved acceleration. The 4R70W planetary gearset, with its improved first-gear ratio, also offers better acceleration. In line with that, the 4R70W gearset can be swapped into an AOD if you are out to get better 2.84:1 to 1.55:1 1-2 upshift and holeshot.

2. Locking Torque Converter

4R70W uses a locking torque converter, which differs from the split-torque overdrive unit lockup feature evident on the AOD. According to Ford, a locking torque converter was to build a more cohesive engine and driveline package. A throttle tip-in while you are in overdrive, causes the converter clutch to disengage, and the latter leads to improved acceleration and torque multiplication.

3. New-and-Improved Valve Body

You will find a new-and-improved valve body in the 4R70W transmission. There are also two computer-controlled solenoid packages, and these have two shift solenoids and a converter clutch solenoid. Ford claims that this valve body is thicker, which offers more strength and durability. These valves are also made of aluminum, unlike steel in AOD, to offer decrease weight and improved sealing. Other components of the 4R70W are:

4. Front Pump

The 4R70W has a front pump made of aluminum, and it also has a steel rotor to provide better flow at idle and increased lubrication and pressure.

5. Speedometer Drive

Given that the 4R70W is an AOD-based transmission, it also features a speedometer drive.

6. Backup Light/Neutral Safety Switch

The 4R70W transmission has a backup light/neutral safety switch. The output shaft speed sensor is located above the switch, and it functions alongside the PCM to enable the engine and transmission function cohesively.

7. Output-Shaft Speed Sensor and Plug

The 4R70W has its output-shaft speed sensor and plug stationed on the driver’s side. On the other hand, the multiplex plug serves as a backup light/neutral safety switch on the transmission driver’s side.

8. 4R70W Multiplex Plug Connection

The 4R70W has a multiplex plug connection, which enables controlled AOD to operate seamlessly with engine operation. A TV cable is not used to move out of adjustment but electronics to offer precision function.

Evolution of the Ford 4R70W Transmission

Better transmissions are being made from older ones, which does not come as a surprise that the 4R70W has evolved. In 2003, the 4R75W and 4R75E were launched as better variants of the 4R70W. These modified versions have better computer control, given that they use input and output shaft sensors. What is more, better improvements can be attributed to shifting power via the valve body. These enhanced variants also have a more durable overdrive drum, improved front pump, and torque converter.

Other improvements made on the 4R75W and 4R75E include:

- Improved input shaft sensor.
- Gearset durability and torque capacity improvement.
- Refined vehicle speed sensor to fine-tune performance while driving.
- Twenty-four tabs on the 4R75’s ring gear to offer for more precise shift control.
- More programming in the powertrain control module (PCM) to allow use in drive-by-wire vehicles.
- The 4R75W and 4R75E feature two shaft sensors for input and output shafts. However, the 4R75-series transmission comes with a different main case to support both sensors.

The Bottom Line

The Ford 4R70W history and evolution show how far it has come and the updates it underwent to be better than its predecessor. It uses fuel efficiently and makes room for other improvements, which makes your driving experience more enjoyable. Although this is an old transmission, it is still a formidable competitor to newer transmissions from Ford.