Prepping a 3/4 Ton D44 for a TNT Truss

[scorpion]

There have been a few good write-ups on our trusses over the past couple of years but none to date and the authors of them have done a good job documenting the little tricks yet there still seems to be quite a few questions as to the easiest way to successfully do this install. The general tech discussion area was selected because the install of a truss, given the procedures, should not be considered advanced fabrication and engineering as no fabrication or engineering is required to successfully do the installation.

This particular install documents the installation of a T&T Customs Heavy Duty Truss on a Dana 44 3/4 ton housing. This housing is fairly simple to identify by noting just a few details of the housing.

The obvious first indicator is, of course, the Driver’s side location of the center casting and that the casting itself is a high pinion. The second indicator is the 2 leaf spring mounts. First is welded directly to the long tube (passenger’s side) and the cast in spring mount on the driver’s side.

This dana 44, when compared to other high pinion Dana 44’s, is unique because it has an overall measurement 1 inch longer on the passenger’s side only. The only drawback of using this differential is that the passenger side axle shaft is 1 inch longer and, when looking for replacements, can only be found in vehicles running this specific differential or ordered from an aftermarket manufacturer like Alloy USA.

 

[scorpion]

The installation of the truss is not a difficult task and can be done fairly quickly if the tricks are made public. . The general tech discussion area was selected for this information because the install of a truss, given the procedures, should not be considered advanced fabrication and engineering as no fabrication or engineering is required to successfully do the installation.

The first step is to remove the perch on the passenger side of the differential. The most common way to do this is to use a grinder to grind away the welds on either side of the perch. Avoid digging into the tube itself and focus your efforts on the perch. As you begin digging into the perch, you will see a hair-line crack develop which lets you know you’re beyond the penetration of the weld. As soon as it is exposed on either side, a BFH and a few good whacks will knock it off.

Step two is fairly easy. As illustrated in the picture below, we’re going to need to remove the front ear off of the driver side spring mount.

 

[scorpion]

The measurements of this ear are as follows. On the front, measure down on either side of the face (front side) 7/8” and mark a line. On the top, measure in 9/16” in and mark your line.

 

[scorpion]

On the outside of the casting, make a dot ½” down from your top line. Now connect your face and top lines to the dot you just made. This is the material you are going to remove.

 

[scorpion]

There are a few ways you could remove this material but, by far, the easiest is to use a cut-off wheel and a steady hand. Follow the illustrations below.

 

[scorpion]

The same process will be repeated in the rear. Measure in on both of the ears 1.25” and mark the top of the casting. You are going to remove the two ears completely but it is unnecessary to remove any more if you don’t want/need to.

Mark a line on the back at the root of both ears. And on the outside, connect the root line to the line on the top as illustrated below.

 

[scorpion]

This time a single pass removes all of the material necessary.

With both of the spring pads out of the way, dropping the truss onto the housing takes only a second. It may be necessary to use a flapper/grinder disk to make slight modifications to the driver’s side if you cannot get the truss to sit at your desired angle prior to welding it on but these notes should save you time and make the install go much smoother. The truss should be set with the top parallel to the ground (or the face perpendicular to the ground). Using a $10 angle finder commonly found at Home Depot will do the trick.

 

[scorpion]

Once the angle of the ¾ Ton Dana 44 Truss, your coil buckets, upper control arm mounts, and trac-bar bracket (if requested) are already installed on the truss for you and no additional welding, measuring, or angle finding are necessary. The last part of the equation is locating the lower control arm mounts. Depending on lower control arm geometry, it is possible to mount the lower boxes where ever they work for your application. In some cases it is necessary to mount the driver’s side in a location that is not possible due to the center casting. Some have ground the bracket to fit over the surface of the casting and others have removed the casting to expose tubing to weld the bracket to. 87XJCO, a fellow NAJXA member, documented an excellent way to make accommodations for the driver’s side bracket.

By marking and removing the casting (which was only added to the center casting as a way to mount the leaf spring – otherwise not necessary), he use a cut off wheel and surgically removed the unwanted cast.

 

[scorpion]

Once the material was removed, the control arm bracket could be easily welded where it is supposed to be located. No tape measure is necessary to locate this bracket. The inside tab should be perfectly lined up under the inside of the coil bucket on either side and the top of the tab should be level to the ground.

You are now ready to burn the truss home. It is recommended that the truss be stitch welded to the housing alternating front to back and side to side. Heavy tacks are recommended near the knuckle end and inside near the casting, both front and back, prior to starting to stitch. This will prevent the truss from walking on you during your first couple of welds as heat can pull the truss around. Make sure you get penetration however be conscious of the amount of heat you put to your differential at any one time. The truss will help prevent your housing from bending but only after it's fully installed.

 

[scorpion]

There appears to be quite a few questions regarding the use of our truss as well. All of T&T Customs’ differential trusses are designed to work with both factory and aftermarket suspension systems. Any kit that can be mounted to the factory brackets can be used with our trusses not just the ones we manufacture. Post up if you have any questions about trusses in general, swapping in diffs, or installs.

T&T Customs

Special thanks to 87XJCO for content.

 

[xcm]

just wanted to thank T&T for their contrib to ....
AND get this bad boy back to the top!

 

[BonesBrosChris]

Thanks for the write up "Scorpion"

 

[Bouncy]

I wish all this information and pictures were available when my truss was mounted.

Great write up.

Note to TNT...The spring perches could use a bit more plate to support the entire spring base instead of only 2/3rds roughly. It doesn't look good having spring hanging off in mid air. Otherwise a good kit.

You may also want to note the axle will be off center unless you cut down the long tube. I believe its off by 1 inch roughly from being centered. Something I knew would happen since I didn't want to shorten the long side tube.

 

[brett3xx]

does anyone have any of these pics saved? there not working anymore?

 

[SoIL4x4]

does anyone have any of these pics saved? there not working anymore?

X2

 

[pm1]

Yes. Anyway to get the pics up again?

 

[XJ jay]

bump