th400 and a dana 20xfr case

[Zorm]

found a dana 20 I might want to swap the current xfr case behind a th400. The dana 20 is mated to a T-15. Would it be a bolt on to the 400 maybe with an adapter or would I need to make changes? I really don't want the 78 chero to always be full time 4x4

thanks for thoughts

[lkmarsh]

Others here and elsewhere have labeled the factory Dana 20 to TH400 adapter
weak. By now they might be hard to find.
Aftermarket adapters are available and expensive.

[Zorm]

right,I have found s few adapters that are aftermarket and are stronger then stock. So, has anyone done this swap? any changes to the tranny?

[Tigger4X]

I think Advance Adapters has tech info on the Th400/Dana20 combo. Coming from a manual you might have to swap out the bull gear(?) inside the Dana. I changed out my QT for a Dana20 and twin sticked it. I don't recall exactly what I had to do thoigh.

One thing I do know for sure is that there are two different pitches of the gears on the Dana20 and that they need to match the ones on your TH400. Im pretty sure I read it on the Advance Adapters website, and not the Novak site.

[rang-a-stang]

If you have a Quadratrac TH400, you will need to swap out the output shaft, too.

[tgreese]

The T-15 has a 6-spline drive gear (bull gear). You will need the 15 spline drive gear, Dana 18-8-40, Jeep 940472. Novak has a chart https://www.novak-adapt.com/knowledge/gear-table/

Looks like the intermediate gear tooth angle is different too. I'd expect the easiest way to use this transfer case is to buy Novak's adapter kit with 6 spline output to match the T-15 the transfer case was mounted to.

https://www.novak-adapt.com/catalog/adapters/transmission-to-transfer-case/th400-to/kit-124/

[babywag]

Best option find a matched used setup.
I found one sorta local iirc $250 for th400/d20/twinstick/aftermarket adapter
Bolted right in on '73 and no hunting down parts.
There are quite a few different parts/pieces on manual trans. vs auto trans. D20(s).

[J20 project]

Yup, 32 spline short shaft th400, D20 adapter between and 18-8-40 trans output/tcase input gear..... Other than that the D20 can take a cv style rear yoke if you get steep w/ lift kit, certainly cv style front. Stock shifter, stock floor pan, etc.

J20