As we mentioned last month, we had decided to go with the folks at T&T Customs for the suspension on the Grand because we had seen some of their work and were impressed. Bob Levenhagen, the chief designer, wanted us to come to their Cheyenne, Wyoming, shop and let them do the installation. But we finally decided that Bob would drive over here (Montana) with the parts and pieces and do the install at our shop. This made it a lot easier on us not having to haul a whole bunch of stuff to Wyoming, such as the front and rear ends and tires and wheels.
When he arrived, we had the Grand Cherokee stripped of all running gear and up on end lift jacks. While it made welding on some of the brackets a bit more difficult than being on a lift, the arms of the lift would have interfered with installing the chassis stiffeners. Just what are chassis stiffeners? As we all know, the ZJ uses what is called unibody construction where the framerails, often referred to as a "subframe," are part of the body and made of stamped and formed sheetmetal. This all works out just fine for highway use, and most off-highway use, but when you get into some serious four-wheeling, well, the body kind of flexes. This leads to cracks around the door pillars and other places that are not desirable. The chassis stiffeners greatly improve or, should we say, prevent this body movement.
1. All the old suspension mounting points must be carefully cut off and ground clean. There is no turning back from this point. | 
2. The chassis stiffeners are installed on each side and welded in place. You had better be an excellent welder to do this. | 
3. Mike cuts off the first-generation lower control-arm mounts from the bottom of the chassis stiffeners. |
Bob's first order of attack was to clean off the subframe rails of all the undercoating and paint-a very nasty job-and to torch off the factory suspension mounts. These don't have to be removed if you're only using the chassis stiffeners with most short-arm lift kits, but they must be removed for the T&T long-arm suspension kit. The chassis stiffeners are best described as a long piece of angle-bent steel with notches cut in the vertical sides to allow conformation to the unibody's subframe. They are held up against the subframe with the bolted-on factory crossmember and then bent into the proper position with a floor- or bottle jack before being welded in place. Keep in mind, you're welding 3/16-inch (7-gauge) metal of the chassis stiffeners to about 1/16-inch (14- to 16- gauge) unibody metal. Let me stress right now that your welding skills better be up to the job, as it is quite difficult. If there is any doubt to your skills, stop now and have a professional welder do the work for you; if it is done improperly, irreparable damage can be done. Bob turned out some of the nicest welds I have ever seen.
Next step was to start on the mounting locations for the control arms. I won't go into any real detail here, as you will see as you read on. The control arms are over twice the length of the original factory stamped arms and made of DOM steel with the uppers being 1.50 inches in diameter and a full 1/4-inch thick, with the lowers being 1.75 inches in diameter and 1/4-inch thick. The axle mounting end has high-density rubber bushings to absorb vibrations, and the frame-mounted end uses a custom high-angularity swivel joint that will provide 60 degrees of total movement and is adjustable for wear, as well as being rebuildable.
4. The new front crossmember is made of 5/16-inch steel plate and serves double duty as both a mount for the front lower control arms and the transmission/transfer case. It utilizes the factory crossmember bolt holes as well as two new ones that come in from the sides. | 
5. Shown here are the three additional bolts that hold the front crossmember mount. Sleeves are installed through the unibody's framerails to ensure extra support, even though the bolts also go through the chassis stiffeners. | 
6. For the new rear crossmember/lower control-arm mount, three holes were drilled through the chassis stiffeners on each side and threaded bungs welded in place. (One is in place in preparation to being welded.) The second-generation chassis stiffeners will have this done already. The first-generation upper-arm mount stayed in place as shown. |