Has anyone done this? How? (Looking for a flat skid plate, already move motor mounts)

First: Make a ring out of ¼” flat plate to fit between the adaptor and D20. Rotate the D20 to all most to the next hole, mark holes on metal ring. Drill holes and then bolt the adaptor to the ring, then bolt D20 to the ring. This is a do-able option, but it places the D20 back ¼”. Is this harmful? I got this idea from a company doing the D300 for Jeep. Even E-mailed the company with this idea and they showed no interest other than to buy their product. I was less than impressed.

Second: Take apart the Dana 20 t-case and re-drill the holes the adaptor bolts to. Well I picked up and extra D20 and opened it up. The D20 has bosses where the bolt screw into the case, so this option doesn’t seem possible and the new holes would have ½ the metal to hold them.

Third: Find a EB D20 that has a completely round adaptor. Then drilling new holes in the adaptor would be an option. Well after looking at over 12 EB D20 for sale I have yet to find this elusive EB D20 with the round adaptor. They all have the adaptor with the bumps that stick out for every hole. I’ve a good friend that has the early D20 from a 66 EB, so I know they are out there, however I was hoping for a C4 one.

Forth: Rotate the D20 one bolt hole rotation. This would clock the T-case 60 degrees, about 10 past horizontal (it’d point up towards the body 10 degrees). This would increase the front u-joint angles on the drive shaft and I’m already worried about this since I’m raising the t-case to level with the frame.

Fifth: maybe I should just do the C4-203-D20 thing after all. (If I win the local lotto, but it looks do-able)

So, any other ideas? (No cheap cops-out posts talking about having some shop do it for BIG$$ or just spend BIG$$ on a kit from company x)

its been a while since I've looked at a bronco d20, but I know that your first plan of making an adapter ring probably wouldn't fly on a jeep 20 even if the bolt pattern was round. Since it uses a bull gear and not a splined out put shaft it would probably cause some gear meshing issues. Do bronco d20's use bull gears? I seem to remember a bull gear on a shaft that hooks onto a splined output on the tranny, but I'm pretty sure I was drinkin beer when it was assembled

The T-shift 20s I've been using and rebuilding have a circular bolt pattern on he front mounting surface, so they can be clocked.

The limitation would be the shift rails. But it can be done with a re-indexing plate like you mentioned.

I would be interested in that as well. I am planning on going to an atlas for a little extra clearance than the dana 20. I think if I push it up against the body (or close) I can get it almost flat. I need to pull mine and see if the AOD adapter from AA can be redrilled.

Originally posted by Charly
The T-shift 20s I've been using and rebuilding have a circular bolt pattern on he front mounting surface, so they can be clocked.


I'm aware they are round, if you read a little further in to my post I said it would probably be a bad idea since it uses a bull gear as opposed to a splined output shaft and that would not let the gears mesh properly. Does anyone have any experience w/ that one?

about the easyest way i can come up with it get a steel adapter, clock the case, and weld the too together(nothing really goes wrong in there anyway). The machining of the plate you talking will be a lot of time invested

here is a pic of mine, its not clocked but the skid plate has become a high cleaance one
http://sierrabronco.com/vShoppingCart-PayPal/skidplatecrunch.jpg

The input (bull) gear is internally splined and sits on the spud shaft, which is supported by a bearing in the "adapter". The end of the spud shaft rides in 13 roller bearings in a counterbore in the output shaft.

So, it doesn't matter, it can be clocked.

Charly

CJ5-man wrote: its been a while since I've looked at a bronco d20, but I know that
your first plan of making an adapter ring probably wouldn't fly on a jeep 20
even if the bolt pattern was round. Since it uses a bull gear and not a
splined out put shaft it would probably cause some gear meshing issues. Do
bronco d20's use bull gears? I seem to remember a bull gear on a shaft that
hooks onto a splined output on the tranny, but I'm pretty sure I was drinkin
beer when it was assembled
You are correct. The input gear for the D20 is attached to the adaptor. So
inserting a ¼" ring would pull the gears out of aliment. I can not see how
this can be corrected and done with longevity. One option would be to
machine of 1/8" from the adaptor and 1/8" off the D20 T-case. This would
keep the gears in the stock position, however it would weaken the adaptor
and D20 case. Another option would be to place the ¼" clocking flat plate
between the adaptor and C4. This would just cause the spline not to ingage
into the adaptor. I'll measure tonight how far male drive shaft of the C4
sticks into the female side of the adaptor. If I remember rights it's
around 1.5". At that depth I wouldn't mind losing a quarter inch. However
if it's a 1 total, I don't like the idea of going to ¾" spline engagement.
Charly wrote: The T-shift 20s I've been using and rebuilding have a circular bolt
pattern on he front mounting surface, so they can be clocked. The
limitation would be the shift rails. But it can be done with a re-indexing
plate like you mentioned.
I forgot to mention both cases are T-handle. Yes the EB D20 has a circular
bolt pattern, however it can't be as easily as you mentioned. Please re-read
the first post. I've bought an extra 20 for a spare case and have opened it
up for review of doing what you said.
inphobic wrote: I would be interested in that as well. I am planning on going to an
atlas for a little extra clearance than the dana 20. I think if I push it up
against the body (or close) I can get it almost flat. I need to pull mine
and see if the AOD adapter from AA can be redrilled.
I've a 2.5" body lift (No pucks though) so that with a torch and BFH should
make enough room. Not sure how much larger the Atlas II is.
welndmn wrote: about the easyest way i can come up with it get a steel adapter,
clock the case, and weld the too together(nothing really goes wrong in there
anyway). The machining of the plate you talking will be a lot of time
invested here is a pic of mine, its not clocked but the skid plate has
become a high cleaance one
I see your point. I just expect to brake the t-case someday, so I want to
stick with a bolt-together system. Plus of the 12 t-case I've seen for
sale, only one has had a C-4 adaptor plate with it.

Looked at the adaptor and C4 side. If I'd make a plate for between the two, at least one hole couldn't be bolted down.
So I'm not happy with this option.

Any other options?

The Early Bronco Dana 20 female adaptor has 3.5" of depth. However the spline count is 1.5" is at the start of the insert.

Just wanted to seeif any more research had been done on this. I am getting closer to attempting this on my own. Thanks, Jake

I guess you could just tilt the whole engine trany transfer case combo in the frame

Anybody thought about contacting Go2Guy for one of his rings? it will fit the bolt patern on the t case I don't see why it wouldn't work.

I'm no ford expert but here goes- if like on the Jeep 20 you are misaligning 2 helical gears by the thickness of the spacer forget it.

If, like the Jeep 300, you simply lose some spline engagement no big deal- as said I'd be looking for an inch or so. Think about how much spline engagement in hubs etc, way after the torque multiplication of low range and the ring and pinion- even less than an inch does not look so bad.

Talk is cheap- if someone want's to "borrow" a ring to mess around and see if it will work PM me and we'll work it out- it's worth it for a learning exercise. BTW- these are machined backwards from the 300 ring for driver side- I do have the ring in stock- some guys are clocking their 231's even flatter.

Thanks,
Ken Blume
Go-2-Guy Engineering

so why not take the adapter down to a local machine shop and have them cut and twist it. cut it and put indexing rings on it? If you did it closer to the transmission side you'd have to make a new cross member to mount it but that wouldn't be too bad. I bet they'd do it for $150 or so if you left it with them for some time. What do you guys think about that?

-Jack

Originally posted by IronBenderII
so why not take the adapter down to a local machine shop and have them cut and twist it. cut it and put indexing rings on it? If you did it closer to the transmission side you'd have to make a new cross member to mount it but that wouldn't be too bad. I bet they'd do it for $150 or so if you left it with them for some time. What do you guys think about that?

-Jack Will not work on the Tranny side, not nice an round like the T-case. Thanks for the idea though.

I ended up twisting the entire case to the next bolt hole, it sits up 10 degrees but I'm willing to live with that.

it should work to cut it in the middle, machine 3/8 of an inch off of each side, put an indexing ring on it and weld it up. If not, why? I wouldn't do this at home because it's cast and it's tricky to weld. But a machine shop shouldn't have a problem with it.

-Jack

This page may be of some interest to you

http://www.broncoii4x4.com/dana20-21/dana20-21.htm

Looks good, but I don't know what the hell I'm looking at. No explanation to go along with.

So does the 21 adapter fit a Bronco adapter and clock it up?

-Jack

D21 supposedly uses a different size bolt circle (smaller on the D21 I believe). I remeber reading that someone was going to try to hook a 435 up to a D20 thru a D21 adapter to keep from paying the $$$ for a custom adapter.