700r4 vs. th400 transmission: Which One To Chose?

With the rollout of numerous automatic transmissions, there is a consistent argument on which is the best for your car. Hence, one of the popular arguments borders around 700r4 vs Th400 and which one is better. With different levels of horsepower, torque, and design, you might face some challenges trying to pick the best option for your car.

But we can make things easy for you!

You know 700r4 and Th400 are products of General Motors (GM) company. While there are huge differences between these two transmissions, they also come with similar features binding the hydromantic transmission technology.

Let’s break it down with a detailed explanation that explores the comparison Th400 vs 700r4, their similarities, strengths, and weaknesses. This will act as a buyer’s guide to help you make better decisions.

700r4 vs Th400 (Side by Side Compression Table)

Transmission4 Speed3 Speed
Manufacturing Year19821964
Type of vehiclesRear-wheel driveHeavy Engine Cars
OverdriveOverdriveNo Overdrive
Weight (without fluid)155 pounds135 Pounds
Gear RatioFirst Gear – 3.06
Second Gear – 1.63
Third Gear – 1.00
Reverse Gear – 2.9
First Gear: 2.48 – 1.00
Second Gear: 1.48 – 1.00
Third Gear: 1.00 – 1.00
Reverse Gear: 2:08 – 1.00
Transmission ModulationShift ModulationVacuum Modulation
Body Length (Inches)23 3/824 3/8

difference between 700r4 and th400 (6 key Differences)

Now, let’s compare these 2 transmissions coming from the two renowned brands based on their features and performance. And 700r4 vs Th400 transmission comparison will surely lead you to a final purchasing decision.

1. Design

The 700r4 runs in different versions, with modifications made on each upgrade to make it better. 

The 700r4 transmission started with a 27 spline input shaft, with upgrades made to 30 spline input. Th400 has a 32 spline count with a larger diameter material. On the other hand, 700r4 has a square oil pan, this is compared to Th400 which has a texas shaped oil pan. 

There are visible distinctions in the bolt patterns. 700R4 has a four-bolt rear output, a tailhousing/adapter pattern with 16 bolts. Hence, th400 has an irregular fluid pan shape, but with a nine-angle, 13 bolt pan design.

2. Overdrive

Th400 is not an overdrive transmission. This is a big difference which Th400 lacks, compared to 700r4. The overdrive feature is fitted to the fourth gear of the 700r4; this offers a 30% increase. 

The overdrive gives a better alternative to direct drive, stepping up the gear ratio of the car. This gives 700r4 a higher speed ratio than Th400. It gives cars with 700r4 the benefits of high speed at low engine power, less vibration and noise, and reduction of frictional effect that can cause engine wear.

3. Horsepower

The issue of horsepower in the comparison between Th400 vs 700r4 has caused a lot of controversies. The 700r4 and Th400- both can handle up to 650 HP. It boils down to why you need a transmission. 

Although you can build and modify your transmission to improve power, if you need something cool that can handle high-performance power, you should go for a Th400. You wouldn’t want to see your 700r4 breaking under intense pressure.

4. Strength and Performance

The primary aim of introducing the 700r4 was to improve a car’s performance and fuel economy. However, especially with an overdrive, 700r4 is not the best choice for a drag race. You can always think of them when you need a transmission for highway driving. 

The Overdrive in 700r4 also improves the durability of your engine and prevents it from wearing out faster. If you need a high-performance transmission for racing, Th400 is a better option. 

Choose 700r4, if you need a transmission for street driving or you ride a dual-purpose car. The overdrive has a great advantage on that.

Choose Th400, if you need a transmission for your trail rig or drives with the need for intense strength and pressure.

5. Usage

TH400 was mostly found in Jeep, Buick, 3sp auto Chevy and GMC trucks, Olds and Cadillac cars. They were a perfect choice for service, strength, and buildable performance in Jeeps and Jeep sports. TH400 was the household name for most heavy-duty cars. 

You can find 700r4 in most rear-wheel-drive cars. That’s too numerous to keep count. From Chevys, Suburban, Camaro, Corvette, Astro Van, or generally any cargo or custom van from the ’80s.

6. Mechanical Operation

Every transmission system has a construction specification that matches its application. Understanding how these works will give ample knowledge on if you can swap a 700R4 with a Turbo 400. Or, will the differences make them incompatible? 

Both transmissions have similar size and construction builds, but the Th400 works with a vacuum modulation. This is different from 700r4 which relies on shift modulation. This shifts control to the output shaft speed, and throttle valve.

th400 vs 700r4 (4 similarities)

1. Construction Material

700r4 and Th400- both are products of aluminum material. Although TH400 is made from pure aluminum, 700r4 is made from cast aluminum. 

The aluminum component of TH400 and 700r4 is fused with a bell housing pattern. 700r4 has a thicker case because it is exclusively for 4 x 4 trucks, but Th400 is for heavy drags.

2. Compatibility and ease to swap

Although TH400 and 700r4 do not come with a similar pan bolt pattern, they share similar alignments in their internal components. Although 700r4 has 16 bolts while TH400 has 13 bolts, with different pan designs, both transmissions use a similar flexplate. TH400 and 700r4 can ensure a 168-tooth flexplate.

3. Manufacturing Company

TH400 and 700r4- both are all products of General Motors. Then came in production in different years; 1964 for TH400 and 1982 for 700r4. However, they are both automatic transmissions.

4. Turbo Hydramatic Technology

The turbo hydramatic technology is more than a brand name for automatic transmissions. This technology oversaw the fusing of a turbine torque converter with a Simpson planetary gear train.

700r4 and TH400 maintain similar automotive technology. They are just upgrades and differences along the history line, in GM’s production of automatic transmissions.

Th400 and700r4: Which One to prefer?

With a detailed comparison of the strengths and weaknesses of Th400 & 700r4, which should you prefer? Well, you should choose the one that meets your needs. 

If you are a daily highway driver, 700r4 is a preferable choice for you. If you are a truck driver with great needs of pressure and strength, a trail rig, a mudder truck, an engine for drag racing, then you should stick to TH400.

People also ask

Can you swap a 700R4 with a Turbo 400?

Yes, you can. 700r4 has slight dimension differences with Turbo 400 which makes it easier to swap any of both in the same engine. 700r4 and Turbo 400 use the same flexplate, although with slight differences in the splines. 

With new driveshafts that match the required length, a good converter, a vacuum source for the modulator, a 700r4 to Th400 swap is possible.

You can borrow the help of a professional auto engineer to help you with the 700r4 to Th400 swap.

Can you run a 700R4 without a computer?

Yes, you can. You can run a 700r4 without a computer. You will need to correctly hook the TV cable to the carburetor with proper adjustment. 

Running a 700r4 without a computer eliminates the need for electronics, putting the transmission on a full manual valve body. It will perform fine without delay or a time-sensitive overlap. The TV cable will handle all shift points and line pressures.

Relevant post:

closing thoughts

There are two major questions you should ask yourself; why do you need a transmission? You need a transmission for speed over long journeys, fuel economy, or strength to handle intense pressure.

We have tried to make you informed thoroughly so that you can reach in your decision of choosing your most suitable one. 

Hopefully, our discussion will build a strong basis that will help you decide between Th400 vs 700r4, which you will prefer.


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Mahir Ahmed


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