This is my first foray into any transfer case. Thankfully it turns out that they’re quite a bit simpler than I thought they would be. I don’t know if the gear driven cases are any more complicated, but my guess is that they’re even simpler.
I’m using the D&D Machine kit from Duffy (he also makes the “Box For Rocks” kits for the Jeep stuff as well). The kit really is quite simple to put together (heck, even a goofball like me managed to get it done without too much of an issue). If you really had to hammer though it, you could probably knock this project out in a day easy (day + plus whatever time you need for the form-a-gasket to cure).
Rear case portion of this is stupid simple to put together (BW1354 case). But before you can slap it together, you’ll need to do something about the breather as it will be in the way of the dobuler adapter plate. Either drill and tap a new one, or make a 90° elbow work as I did. Remove the stock breather and do a little clearance grinding on the case:
After you’ve done some grinding to get rid of the excess T-case stock, you get to start trimming the block off plates to fit. This is the one spot I’m a little disappointed in the kit. It would have been nice to have the plates a little closer to the right size (minor complaint, I realize that).After whacking off about 3/8” off the plates, and doing some rough grinding:
You can either have these welded on, or just use some form-a-gasket to seal them off. I opted for the latter as this is just an Aluminum transfer case, I want to be able to pop these blocks off in the future if something were to happen the doubler case.
After the sealant has set on the front case, slap some sealant on the surface between the adapter plates and screw them together. This is my only other complaint about this kit. Instead of having the shift rail screwed to the back side of the adapter plate (another place to possibly leak). It would have been nice to have the rail ‘float’ instead which would allow you to pull the shift fork out while tightening down these screws. Getting under the shift fork is a pain for folks with big hands! TIP: Drill a hole in the sift fork to allow you to get to the allen bolt underneath it (I forgot to do that, it would have made life easy). This is also the point in which you get to decide to clock the rear case if you want. I left mine stock at this point to keep from having to clearance the cab too much:
Plop the shaft in and slide the planetary set back into the front of the case (It helps to rotate it as you insert it). Don’t force it! It will slide in easily once everything lines up. Give everything a spin to makes sure it feels good while you’re at it. (And yes, you’re allowed to giggle as you make it spin in double low while its on the bench).
Now you just need to address the vent tube for the front case. In the latest revision of this kit, Duffy put a tapped hole on the adapter plate to be used for a vent. Since that hole sits higher than the stock vent, it’s wise to just plug up the stock vent tube hole:
For the Main vents, I made them “T” into each other to less the amount of lines running around under my truck. At this point I think I’m going to run the vent line out back behind the cab, but that’s subject to change once I get the doubler under the truck.:
Fill it up with fluid (about ¾ of a quart) and slap it in the truck (I don’t have it in my truck yet so no pics). It looks like I’m going to get lucky with the linkage as my case came with the 1350 linkage for the AL4D. So it should work with my M5OD tranny and make life simple. If not, I’ll make it work.
As a side note, when looking at the guts of the 1350 and the diagram of the 1354E. I’m thinking it might be possible to take the mechanical linkage out of a 1350 and make it work in the 1354E case to lose the electric shift motor. If I come across a couple of cheap cases in the future, I might have to give this a try.
As another side note, If you have a spare 1354 laying around, you can pull the Planetary, shift fork, and slide gear to upgrade form the 4 gear set to the 6 gear set (1993+ 1354’s). I didn’t have that luxury, so I’ll just rock the 4 gear set. If it breaks, I’ll worry about it then.
The doubler adds 6.75″ to your driveline