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post #1 of (permalink) Old 04-11-2002, 08:48 AM
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Dana 20 low range conversion

I currently have a Dana 18 mated to an SM420 with an AA Adapter. I am interested in converting to a Dana 20 so I can change out my rear axle to a centered diff.
Has anybody swapped the gears from an 18 to a 20? I need to know if I can do this and still use my adapter for the tranny. The adapter uses a new main shaft for the tranny so I want to be sure that the 18 input gear will work in the 20.
Will any Dana 18 gears work for this swap or do I need to check to see if I currently have a compatible 18.
Any advise on this is greatly appreciated.

Also, if anybody knows any good web-sites covering this topic please let me know.

Thanks for your input.
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post #2 of (permalink) Old 04-12-2002, 06:37 PM
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Re: Dana 20 low range conversion

You'll need a D20 case and a large front bearing adapter. You will need to grind the D20 case a little to clear the larger gears out of the 18. You'll also need a bronco rear upper sliding gear, 18-8-58 for the rear drive. Make sure the intermediate shaft from your 18 matches in diameter with the 20. You could always bolt on the 20 case as long as you got the right input gear, but the 20 low is only 2.03 compared to the 18's 2.46. Be careful not to mix gears, there are two different gear pitches between the cases. Check out the info base at Novak adapters, it'll get you all the info on the 18 and 20 that you'll need.
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post #3 of (permalink) Old 04-12-2002, 07:23 PM
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Re: Dana 20 low range conversion

Do a search at the regular off-road.com website. They have a write up on this. I was thinking about one of the aftermarket kits myself--drops the low range to 4:1 according to the advertisment. Not sure of the cost of it yet.
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