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What is a Crossmember?

What is a Crossmember?

A Transmission Crossmember Resists Deflection and Twisting

G Force Performance is the exclusive manufacturer our patented transmission crossmember line explicitly designed for the Make, Model and Year of your vehicle. We are also a well-known producer of transmission adapter plates, flywheels, transmission swap kits, and other automotive parts needed for transmission conversions. From our first transmission crossmember patent, we concentrated on making exceptional parts that support car enthusiasts with achieving their automotive objectives.

G Force Transmission Crossmember and Next Generation Crossmember

Today, G Force Performance engineers continue to live up to our reputation by creating innovative designs and manufacturing top-of-the-line parts. Consequently, we spearhead innovation in the automotive aftermarket throughout our transmission crossmember line and for our various types of adapters, motor mounts, and transmission conversion kits.

 To understand what a crossmember is, you must first know a little about a transmission swap.

Transmission Swap Defined

Installed G Force crossmember

Basically, a transmission swap involves switching the OEM transmission to a different one. Frequently the alternate transmission was not offered as an option for the vehicle. Usually, the term swap refers to the most common type—an automatic to a manual transmission conversion. However, swap can also mean any change for performance advantages, whether manual to manual, automatic to automatic, automatic to manual, or manual to automatic. Any combination is viable, and each has its challenges and benefits.

Why Swap?

Car enthusiasts choose to swap transmissions for lots of reasons—
  • For improved fuel efficiency
  • To eliminate recognized OEM vulnerabilities
  • To get a vehicle running again
  • For better performance benefits
  • To better handle heavy load situations
  • As part of a motor swap

An Example of Transmission Available Options

There is almost always more than one transmission option for any swap scenario. For the beginner, the choices can be confusing. As an example, the 4L60, 4L60E, and 700R4 are all 4-speed automatic 

transmissions. In actuality, they are modifications made to the same transmission produced by GM from 1982 to 2013 for use in trucks and rear-wheel-drive cars. However, a careful look exposes the distinctions. In 1982, the 700R4 started to replace the TH350 3-speed transmission. By 1987, the original design issues were overcome, making the 700R4 much more reliable.

Then in 1990, even though it was effectively the same engine, GM altered their naming conventions, and the 700R4 transmission became the 4L60. Three years later, it was introduced as the 4L60E when GM modified this transmission from mechanical controls to electronic. Because of that switch, certain adjustments like altering shift points and torque converter lockup were more straightforward. These changes, among others, now could be made through a software program. Making the same adjustments on earlier versions of this transmission required taking the transmission apart to make the same modifications mechanically—a time-consuming process.

What the Experts Say

Many authorities on automotive transmissions regard the 700R4, 4L60, or 4L80E as some of the best 4-speed automatic transmissions ever manufactured. Not surprisingly, it is a common transmission swap. The 4L60 often is chosen for fuel economy improvements and the fact that its first gear ratio of 3.06:1 delivers better acceleration and superior off-road driving. Experienced car enthusiasts and novices choose it because of its popularity and longevity on the market. However, many fans still favor the 4L60 or 4L80E transmission because of the improvements made to it over the years.

Other Options

However, other options to replace the 700R4 are available, and examples include the GM Tremec, TKO-500, TKO-600, and GM-T5. Anyone completing a swap, especially the inexperienced, should investigate their transmission options thoroughly before deciding. 

 You can learn more about a LS swap; check out our FAQ here. The Chevy S10 is also a popular swap. Learn more about an S10 conversion here.

What About the Crossmember?

Because of transmission swaps' popularity and sometimes its necessity, many aftermarket parts are manufactured to make a conversion easier. G Force Performance Products specializes in designing, engineering, and manufacturing parts for transmission swap aftermarket. We offer a comprehensive transmission crossmember line and associated components for a swap, such as transmission mounts, adapter kits, and other accessories.

What is a Transmission Crossmember used for?

Transmission Crossmember Collection with G Force patented dual hump design

A Crossmember is a steel-reinforced bar that bolts across the vehicle to support the transmission. Strength, durability, and a good fit are critical to proper handling and body panel alignment. Also, the crossmember must be strong enough to resist deflection and twisting. That’s why G Force Performance has extended our crossmember line to include various body types, transmissions, and motor combinations.

Most importantly, a G Force Performance crossmember is guaranteed to fit like your factory transmission crossmember. Unless there are unusual circumstances, reworking the mounting locations is not needed. We’ve removed the need for welding or cutting for a perfect fit by engineering a bolt-to-frame design.

Each G Force transmission crossmember includes installation instructions, and most come with mounting hardware. Rest assured that G Force Performance established stringent standards to ensure each transmission crossmember stands up to stresses of even the most strenuous load. In addition, our double-hump design allows plenty of room for your exhaust system.

Because Sometimes Weight Matters

For a lighter weight crossmember option, G Force re-engineered four of our most popular transmission crossmembers because sometimes weight matters.

For car buffs, as well as race car drivers, weight is a significant factor in part selection. Weight impacts every alteration made to their cars. Lowering curb weight (the total weight of the car without a driver) has benefits, and a lighter weight transmission crossmember is one of many aftermarket options that can lessen the load.

Why is Weight Important

Any quantity of weight added or deducted from the vehicle has a bearing on performance. When carefully eliminated to balance out the load, a reduced curb weight makes better handling, faster braking, and more rapid acceleration possible. Less weight ultimately reduces emissions and fuel consumption because the engine doesn’t have to work as hard to move the car.

Generally, a ten percent weight reduction has an equivalent effect on the force needed to slow down or speed up an object, and the same rule pertains to vehicles. Simply said, with everything else being equal, a balanced weight reduction means a better lap time for the road racer or drifter.

We Heard Your Requests

The result, four new lighter weight transmission crossmembers

G Force Next Generation Light Weight Crossmember selection

While G Force has a strong reputation for the durability, strength, and reliability essential to our crossmember design, our customers requested a lighter weight option to help them balance their vehicles' curb weight. As a result, our engineers revamped four of our crossmember bestsellers and reduced their weight by at least 20%.

To ensure the next generation crossmembers meet G Force standards, they were independently tested for Load vs. Deflection. The test results showed a negligible difference in strength when compared to the legacy product.   

Above all, each lighter weight transmission crossmember retained the traits that make G Force a leader in the suspension and transmission industry aftermarket. Keep in mind, enhancing our parts does not stop at fitment. Our specifications ensure that the next generation of products tolerates the challenges of the racecourse or road.

For example, when compared to the original RCG-700 crossmember, the RCGNG-700 Next Generation version registered only a minimal change during the Load vs. Deflection testing—a difference too small to be seen by the naked eye. At the typical load for an installed transmission (200 lbs.), the legacy crossmember deflection measured 0.075” (up), 0.096” (down) as compared 0.089” (up), 0.111” (down) for the lighter weight version (see graph below). Similarly, tests of other Next Gen crossmembers showed comparable results.   

Load vs Deflection Test Results

G Force Next-Gen Transmission Crossmember Details

The four next-generation Crossmembers fit popular years and body types, including 1964 – 1967 and 1968 – 1972 A Body as well as 1984 – 1988, 1978 – 1988, and 1978 – 1983 G Body vehicles.

Complete information regarding make, model, year, transmission for each legacy and Next Generation crossmember is available in the product details.

What is the G Force Crossmember Difference?

There are a variety of reasons why our customers choose a G Force crossmember, and here are just a few.

 

Bolt-to-Frame Installation

 

G Force specifically developed each

crossmember for your Year, Make, Model, and transmission combination. Therefore, when you select a G Force crossmember, we guarantee it fits the same as your factory transmission crossmember.

When you opt for G Force, you use the existing mounting locations and hardware without modification. Our bolt-in construction means cutting, and welding is not required making your installation a breeze. Plus, installation instructions come with each transmission crossmember and include all the details you need.

Next Generation Crossmember Load vs Deflection

Tested for Strength

 

Product design and engineering do not stop at fitment, which is why we set our standards high. And, because of that, you know your G Force crossmember will hold up to the most demanding loads and road challenges.

Every G Force Crossmember is Made in the USA

Each crossmember is proudly made, assembled, and packaged in the United States, guaranteeing our customers receive the highest quality product for their needs.

New Hardware Included

We’re car enthusiasts as well as automotive manufacturers, which means we understand that working on classic vehicles means old bolts. For easier installation, G Force includes installation hardware with almost all of our crossmember kits, and it’s just a little thing we do to make sure your project goes smoothly.

Double-Hump for large-diameter dual exhaust

We believe a crossmember that doesn’t retain its functionality isn’t worth installing. So, we take the extra step to provide our “Double-Hump” design to make certain there is enough room for your aftermarket or factory exhaust system.

A G Force Crossmember is Engineered for Performance

Our crew of enthusiastic engineers concentrates on developing top-quality products for our customers. Each part is thoroughly tested and designed for proper fitment, durability, and strength. G Force crossmembers continue to revolutionize the suspension and transmission industry.

Exceptional Support and Customer Service

G Force Crossmember Collection

Although we design products focusing on ease of installation, we know that every project has its challenges to surmount. You can be sure that our Customer Service Team has the experience and knowledge to help with your selection of the best crossmember and transmission swap kit for your project. In addition, we can assist you with purchasing the right transmission crossmember for your project. Our Make, Model, Year search at the top of our home page is the best place to start. If you still have questions, there is lots of information below, which is also available in our online guide, or you can always chat with us.

How to Choose the Right Crossmember

Please note that G Force created the Transmission Group Chart to make finding the proper Crossmember for your project easier. For reference purposes, please use the charts and tables below to find needed information such as the appropriate Transmission Group, Body Classification, Transmission Notes, and the Crossmember Part Number you need for your project. Plus, following the “How to” section, you’ll find our complete cross-reference guide.

Using the Transmission Crossmember Specifications chart:

Step 1- Begin by finding the Body Classification for your vehicle. The Body Classification also is referred to as ‘Body Type.” If you don’t already know yours, look for the year, make, and model of your car in the Body Classification Notes below or find it on our full list of body types. Once you've found your car, jot down whether it's an A, C, E, F, G, S-10, X, Y, etc.

Step 2- Look in the Transmission Group Chart for the section for the Body Classification for your vehicle. If it is listed under multiple Body Types, match the model year for the correct classification.

Note that different transmissions can share measurements such as the same overall lengths. They often require the same transmission crossmember. We created the Transmission Group Chart by grouping the transmissions that can share the same crossmember.

Step 3- After you’ve found the correct line for your Model Year and Body Type on the chart, note the Transmission Groups that fit your Body Classification. On this line, you also will find the Crossmember Part Number associated with the appropriate Transmission Groups. Keep it in mind for Step 5; you'll refer back to then.

Step 4- Now, look up your transmission in the Transmission Notes section and jot down the associated Transmission Group. If you’re not sure which transmission you have, look at our list of Popular Transmission Pan Patterns to see if you can identify your transmission.

Step 5- Refer to the Transmission Group Chart (found in step 3) and jot down the Crossmember Part Number that matches your Transmission Group and Body Classification.

Step 6- Congratulations! Now you can place your order! The final step is to search for the Crossmember Part Number you wrote down in Step 5 and add it to your cart. Complete the checkout process, and your new transmission Crossmember will be on its way to you.

Let’s work through an example.

For this example, we'll assume you own this car

Make: Chevrolet
Model: Monte Carlo
Year: 1975
Transmission: TH350

The Monte Carlo falls under two Body Classifications, "G" and "A," subject to the model year.Body Classifications for this example: 

GM A BODY: Intermediates, i.e., Malibu, Monte Carlo, El Camino, Skylark, GS, Cutlass, GTO, Regal, Chevelle, etc. 

GM G BODY: Intermediates, i.e., Chevelle, Monte Carlo, Malibu, El Camino, GS, Skylark, Cutlass, Regal, GTO, etc. 

However, your model year is listed for the "A" Body only. GM G Body was launched in 1978.

Body Classifications for this example: 

G Force Crossmember

GM A BODY: Intermediates, i.e., Chevelle, Monte Carlo, Malibu, El Camino, GS, Skylark, Cutlass, Regal, GTO, etc. 

GM G BODY: Intermediates, i.e., Malibu, Monte Carlo, El Camino, Cutlass, Regal, Grand Prix, etc.

However, when you look at these sections of the Transmission Group Chart, you'll see your model year listed for the "A" Body only. The earliest year for the GM
G Body is 1978.

Transmission Group Chart for this example:

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Transmission Notes for this example

GROUP GM-1: TH350, MUNCIE, POWERGLIDE, T-10, SUPER T-10, SAGINAW, TH200, etc.

GROUP GM-2: 700R4, 4L60, 4L60E, TKO-500, TKO-600, etc.

GROUP GM-3: 2004R, TH400 SHORT TAIL, etc.

GROUP GM-4: 4L80E, 4L85E, etc.

Using this information, the possible Transmission Groups for your car are GM-1, GM-3, GM-2, and GM-4. Also, the possible crossmember part numbers are RCAL, RCAL-700, and RCAL4L80.

The next step for determining the correct Crossmember Part Number is to find your transmission (TH350) in the Transmission Notes section.

It’s listed under GM-1. The last step is to look up the Crossmember Part Number for the GM 1 Transmission Group—refer to the Transmission Group Chart. A section of the chart is shown above. For our example, the correct Crossmember Part Number is RCAL.

It’s easy to find the right Crossmember and G Force customers pick our crossmembers for toughness, stability, and hassle-free installation. 

CROSS-REFERENCE GUIDE

Lookup the proper Crossmember for your project

Body Classification Notes:

The most popular makes and models are shown below. Find a complete list on the Car Body Types page.

GM A-BODY: Intermediates, i.e.,  Malibu, Monte Carlo, El Camino, Skylark, GS, Cutlass, GTO, Regal, Chevelle, etc.

GM B-BODY: Caprice, Impala, Bel-Air, Biscayne, Electra, Le Sabre, Catalina, Bonneville, Delta 88, Starfire, Delmont

GM C-BODY (Truck Series): C10 Pickup

GM C-BODY: Full Size, i.e.,  Electra, 98, Deville

GM E-BODY: Riviera

GM F-BODY: Camaro, Firebird, Trans Am.

GM G-BODY: Intermediates, i.e., Malibu, Monte Carlo, El Camino, Cutlass, Regal, Grand Prix, etc.

GM S10: S-10 pickup, S15 pickup.

GM X-BODY: Nova, Chevy II, Ventura, GTO, Omega, Apollo.

GM Y-BODY: Corvette C3 gen

GM UNIVERSAL Kit

Olds Bravada

Ford Mustang

TRANSMISSION NOTES

The most popular transmissions that share the same Crossmember are listed below. Find a complete list on the Transmission Groups page.

GROUP GM-1: TH350, MUNCIE, POWERGLIDE, T-10, SUPER T-10, SAGINAW, TH200, etc.

GROUP GM-2: 700R4, 4L60, 4L60E, TKO-500, TKO-600, etc.

GROUP GM-3: 2004R, TH400 SHORT TAIL, etc.

GROUP GM-4: 4L80E, 4L85E, etc.

GROUP GM-5: OEM T-56 (SWAP FROM LATE MODEL F-BODY)

GROUP GM-6: 6L80E (Slip Yoke), 6L90E (Slip Yoke)

GROUP GM-7: 8L90E (Slip Yoke)

GROUP GM-8: 700R4 (Tailshaft Mount Trans Mount), 4L60E (Tailshaft Mount Trans Mount)

GROUP F-1: AOD, TREMEC, etc.

Transmission Group Charts

GM A-Body Chart

GM B-Body Chart

GM C-Series Truck Body Chart

GM C-Body Chart

GM E-Body Chart

GM F-Body Chart

GM G-Body Chart

GM S10-Body Chart

GM S10 Blazer & Jimmy Body Chart

GM V-Body Chart

GM X-Body Chart

GM Y-Body Chart

GM Universal Kit Chart

Old Bravada Body Chart

Ford Mustang Body Chart

G Force has put together lots of helpful information about our crossmember products. Check out these pages to learn more.

What if you do not have the correct transmission crossmember for your build?

G Force Adjustable Transmission Mount

If you do not have the correct transmission crossmember for your build or have installed a transmission that positions the transmission mount forward, selecting a crossmember combined with a G Force Adjustable Transmission Mount may solve your problem.

The first thing to consider is the engine conversion itself and how it has affected the drivetrain location. With some engine swaps, the engine is relocated forward between 1" and 2". Our adjustable transmission mount alignment of the crossmember when the drivetrain is moved forward.

If you want to know more about a transmission swap or a transmission crossmember, you may find these blog articles from G Force useful.

 Learn about a LS swap, Cummins conversion, G Force crossmember, and more.

Transmission and Crossmember Technical Information

 Discover the G Force crossmember, transmission mount, LS swap, Cummins conversion, and motor mount difference.

Our Commitment

Happy customers are the highest priority at G Force Performance. We carefully test and design our products for strength, weight, and fitment without compromise. We continue to lead the transmission and suspension industry with our innovative products. Our dedicated crew is ready to assist you with the application support you need. 

Questions?

Live Chat or give us a call at 330-753-5300

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