Dana 18 Gears In A Dana 20 For A 2.46:1 Low

First off I’d like to thank Nickmil whose original post made my successful build possible.

The purpose of this post is to clarify and inform members how to change the gears in their Dana 20 transfer case to a higher numerically 2.46:1


Here is a list of what is needed to make a 2.46-1 low range model 20:

If you find a used Dana 18 with a 1 1/4” intermediate shaft you can get most of the gears that way. If like me, some of your donor Dana 18 gears were damaged you can order all the gears new from Novak Adapters. The downside is that it greatly increases your cost. Gears cost between $90.00 and 160.00 each. I had two of the five gears so I spent a total of about 350.00 on gears.


1) stamped number on the gear: 18-8-23, a 29 tooth 6 spline input gear Novak Adapters PN: 809297

2) stamped number on the gear: 18-8-22 Novak Adapters PN: 809290

3) stamped number on the gear: 18-8-24 Novak Adapters PN: 809291

4) stamped number on the gear: 18-5-9 intermediate gear Novak Adapters PN: 809293

5) stamped number on the gear: 18-8-37 slider gear from EARLY Bronco 20 Not Available from Novak it appears to be exclusively available from Tom’s Off-road Tom’s PN: 5014RS

https://tomsoffroad.com/parts/66-72-ford-bronco-dana-20-transfer-case-rear-slider-gear

“The rest is bolt up except you may have to grind some on the case (most do) to clear the slider gear. Sometimes you have to grind the pan rail/opening to get the intermediate gear in also depending on which assembly order you go in. I'd recommend checking it so down the road if there is a problem you don't have to disassemble the whole transfer case to get the intermediate gear out. Nickmil.”

 

Thanks for posting this. I bought the Bronco gear to do this swap in my Commando but I haven't actually done it yet, I'm waiting for my AT swap.

 

I kinda went down this road except I built a D 18 in a 20 case, nothing real trick there, it's the same case but the later dana 20 seemed to have more "meat" in the casting.