I see this question has been posted a couple of times but it hasn't been answered so here goes again:

I've pulled a Dana 21 single speed t-case from my '72 F-100. A search of the web led me to believe I could swap in a Dana 20 out of an older Bronco to get low range. I got a good t-case off the internet but now that they are both sitting on my work bench I have a problem. The output shaft on the truck (4-speed, T18, I believe) does not match up with the gear on the Dana 20. I took the correct gear out of the Dana 21 in the hopes I could transfer it into the 20, but I'll admit I haven't been able to figure out how.

Anybody done this or have any ideas? This is my snowplow and snow's coming...

 

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Most swap info I have come accross for swapping a T18 or NP435 into a Bronco with the Dana 20 has said to use a 2wd transmission, not a 4wd, because of the different output shafts on the tranny. There are kits for Broncos to hook up a 4speed to a Dana 20 in a Bronco using the 6 cylinder adapter housing and a 2wd 4speed. You may want to contact www.advanceadapters.com, www.wildhorses.com or www.broncograveyard.com and see if they can come up with something for you.

An easier way to get the low range in your truck would be to use an NP205 instead. Should have no problems hooking the 205 up to your 4speed .

 

Ahh crud. I went with the Dana 20 thinking a Ford Bronco and a Ford F100, same year, would be an easy swap. D'OH! I've heard that 2WD/4WD thing before.

Is the NP205 a direct bolt-up, in case I have to abandon this Dana 20 and start all over? Again, I'm pretty sure the tranny is a T18, but it might be a NP435 (can't scrape enough of the oil and grime off the case to see if the cover is aluminum...). The truck is a bit of a parts bin ('69 motor, '72 chassis, '77 cab, '75 bed...) but it takes a lickin' - just need a bit more traction for when the snow's three feet deep.

 

I have a 435 that had a Dana 21 on it and the output shaft is different than a 435 for a 205 transfer. The best thing would be to find a trany and transfer together and put it in. You will need to do some driveshaft work too.