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New Body, Motor, Transmission & Transfer Case Mounts for an Old 4x4

Posted in How To: Body Chassis on October 19, 2017
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We love old 4x4s. Maybe it’s because they’re easy to work on and remind of us a simpler time and a calmer pace of life. Maybe it’s their smell, shape, look, and style. Or maybe it’s some unknown magnetism that they develop cruising down backroads around the USA. Whatever the reason, we love them.

What we don’t love is the toll that time and use take on our beloved classic 4x4s. Metal rusts. Rubber deforms, dries, cracks, and rots. Pretty soon our old 4x4s don’t perform the way they once did. The good news is most of this can be fixed. Rusty metal can be treated or cut out and replaced, and bushings can be rebuilt or replaced with better, modern materials that not only revive but improve our old 4x4s.

Enter Energy Suspension. For the past 30 years Energy has been reengineering rubber OEM parts, producing products in polyurethane that meet and exceed the properties of original-equipment rubber parts. Such products as body mounts, suspension bushings, and drivetrain isolation mounts (engine and transmission mounts) are offered for a wide variety of vehicles both foreign and domestic. Energy does this by studying the OEM parts and tweaking the design by using durable polyurethane rather than rubber. Polyurethane has many benefits over traditional rubbers, but the most important are that it can easily be tuned for different harnesses and it’s less susceptible to damage from oils, other automotive fluids, road salt, dirt, and other debris.

With a passel of old 4x4s in the 4WOR fleet it was high time we upgraded one with some parts from Energy Suspension, and we hope to install more soon. Follow along as we de-rubber the squished, rotted bushings in our 1970 Chevy Suburban, Dino, with high-quality polyurethane replacements from Energy Suspension. And if you don’t own a Chevy don’t worry—parts are also available for old Fords, Dodges, Hummer, Jeep, Isuzu, Lexus Nissan, Toyota, Scout, Suzuki, and more.

We started upgrading our old 4x4’s rubber wear parts to Energy Suspension polyurethane by hosing down with high-quality penetrating lube all the nuts and bolts we knew we were going to be taking apart. Doing this a week or so in advance allowed the penetrating oil plenty of time to loosen up any rust on the bolts. Our old truck is fairly rust free but still showed plenty signs of the cancer. We knew the body mounts were going to put up the biggest fight, so we started with them.
Only work on one side at a time. You can loosen the body mounts slightly on one side of the vehicle and then remove the body bolts of the other side. The lower bushings remove easily, but the bushings between the frame and the body require lifting the body. We used a floor jack and a couple large pieces of wood. Make sure you’re using a strong part of the body to lift it to prevent damage. Having a pair of clear safety glasses is a must since dirt, rust, and little bits of the old body mounts seem to like nothing more than falling into your eyes.
Many vehicles have body mounts that are only accessible from inside the truck cab. Four of these bolts had a couple heavy tack welds to Dino’s floor. We used a hobby rotary tool to cut the heads of the bolts and then cleaned up the weld with a pneumatic grinder. The Energy Suspension body mount kit came with new bolts to replace any and all factory hardware.
With the old bolts out of the way and the body slightly raised, we were able to fish out the rotten old upper body mounts one or two at a time. Remember you have to loosen the body mounts on the side opposite where you’re working to allow the body to lift enough on your side and also to avoid damaging the mounts. Otherwise there probably will not be enough clearance created on the side you’re replacing to fit the new bushings between the body and frame.
With the opposite side bolts loosened but not removed, we got just enough clearance to allow the new, unsquished Energy Suspension body pucks in place.
The comparison is stark between the old original body mounts and the new ones from Energy Suspension. The factory rubber bushing was very collapsed, hard as a rock, and brittle. The space inside the sleeve is apparently a trap for moisture and thus rust. The Energy steel parts are coated to prevent rust, and you can see that the polyurethane parts are reinforced with steel components cast into the body of the bushing.
Check out this factory body bolt on what is only a moderately rusty truck. It’s just about rusted through. If that rusts all the way through, the body can flop around on the frame and cause body damage, strange ride characteristics, and spectacular failure during an accident.
The body mounts under the radiator core support were in really bad shape. The rubber was rotten and ready for the trash. Any of these collapsed factory bushings can cause the body to lean to one side or front to rear.
Any truck that has been used extensively off-road or one that has over 150,000 miles (Dino has had both) probably has wear not only in the body mounts but the drivetrain mounts too, so we decided to upgrade our engine and transmission/transfer case mounts with poly components from Energy Suspension. With that, we moved the floor jack under the engine and first pulled the engine isolation mounts. These mounts were in pretty good shape, but an ounce of prevention is worth, um, not being stranded on the side of a dirt road or trail. A comparison shows the Energy Suspension parts are well thought out, including eliminating the captured nature of that lowermost motor mount bolt hole. What was GM thinking?
With the old engine isolator mounts out, the new polyurethane units are easy to install. The kit comes with preload spacers that must be used. As a result, we swapped to slightly longer Grade 8 bolts and lock washers.
The transmission and transfer case mounts were comically easy to replace on our 1970 Suburban. The new and old parts look similar, but we know the new parts are superior mostly because the old parts were absolutely soaked in gear oil, which can cause them to break down over time and easily tear when given a healthy dose of rotational torque.
We used a floor jack under the transfer case to lift the drivetrain, and with a couple of wrenches and a pneumatic impact we soon had the old mounts out and the new mounts in. Our Suburban has these locking tabs that had to be bent to allow removal and to prevent the bolts from backing out.
Our 4x4 has an NP205, which can handle huge amounts of force. One thing that helps these parts survive is the way they are mounted to the frame. Four donuts help isolate the drivetrain from the frame and prevent torque twist from moving the transfer case, transmission, and also the engine. The Energy Suspension kit came with four new polyurethane donuts, and new steel spacers. We reused some of the bolts and all the brackets and upgraded the two 3/8-inch bolts that go through the side of the frame to Grade 8.
Aftermarket tie-rod ends often come with questionable rubber boots that crack and fall apart quickly. That’s not good, and Energy Suspension has a solution to this problem in the form of polyurethane tie-rod end boots. These boots are made out of polyurethane and will last a lot longer than the cheap replacement rubber boots.

Sources

Energy Suspension
San Clemente, 92673
888-913-6374
http://www.energysuspension.com

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