How to Remove an Overdrive

How to remove an Overdrive from a Dana 18 transfer case:
1. Remove the five Outer mounting bolts Only, These should have a 9/16″ head. these attach the aluminum housing of the rear assembly to the transfer case only. Do not remove anything else(as long as the linkage pin is removed from the ship shaft already).
2. Now you should be able to get that aluminum housing to come back a little, so that you can put a flat blade / mini prybar in-between the aluminum housing and the transfer case.
3. Be careful not to damage the aluminum housing when you pry from each side of it.
4. What’s happening is a cage bearing inside of a part called a spyder blank (part of he complete planetary) shrinks and conforms to the shape of the cage bearing housing making it a tight fit.
5. You have to pry evenly because if  you don’t you may make it tighter to remove. When you have it back far enough that your screwdriver is too small, then add a piece of wood or a tool as a shim and continue until it is removed. This is the only way to remove the rear assembly without causing possible damage to other parts.
6. Removing additional parts from the aluminum housing at this point is not advised.
7. Next remove the internal, odd square type,  snap ring inside the planetary/barrel assembly inside the t/f case by compressing it lightly inward. A small flat blade or pick can help.
8. The next part is the tab washer. Now this part serves the purpose of a lock washer as it locks the drive nut from turning (unscrewing) when the OD is installed. It may be tight, if so carefully use a 3/8” extension and wiggle it inside the tab washer and that
should allow you to remove it.
9. Once the tab washer is removed, take a ½” extension and unscrew the drive nut inside the planetary to remove this from the transfer case. The drive nut will not come out as it is locked into the planetary assembly. NOTE: If this is extremely difficult get a high quality extension such as snap-on or Williams, even grinding the end more flat to increase contact depth of the tool if needed.
10. If you have an extremely difficult removal and need some help, don’t hesitate to give me an e-mail or a call and I will try to help you with it.
11. Do not use a torch.  Do not remove any other bolts other than the 5  3½” long bolts. Worst case scenerio, remove the entire transmission/transfercase assembly and send it to me on a pallet if you’re worried about causing damage. We welcome the challenge.

These two complete pieces should be what you see once it is fully removed.

If this is what you see, you will likely need to reassemble the housing in order to pry it off with the shaft.