Twin Stick Conversion

[mattt]

Got the bearing off the front output shaft and it's out of the case now. It took a beating all the way off. That bearing wasn't coming off without a BFH. But it's off, and now for the last shift fork/rail set screw. Still stuck like f**k. I beat a 5mm hex tip into the set screw because the 3/16" was a tad loose from the last two nights. Instead of turning out of the fork, it Ripped what little hex was left in the set screw away. I guess the next try is with a torx tip...hopin' for bite with that baby!

Viperwolf....Thanks a million for all your much appreciated help. If you ever make it to CA....I need to buy you a beer....or 12

Tomorrow.....hopefully finding a source for these set screws with the same taper.....

 

[mattt]

Got the last set screw(or what is left of it....not much) out on Friday evening, 1:04am. I tried every possible SAE and/or metric combo of allen wrench, allen socket, torx tip. That thing was in there. At one point, I had an allen tip snug in the set screw, and thru a series of adapters had a 1/2" drive, 2' breaker bar on the end. The screw wouldn't turn with that combo even....it broke the 1/4" to 3/8" adapter I had in the mix instead of spinning the set screw out.

What finally got it out was drilling and a large ez-out. I hate resorting to these and didn't until I had no other options. I've had too many bad experiences with broken ez-outs.

Looking at the rear shift fork, I have some wear on one side of it at the tips. Pics attached. Is that normal wear for a 40+ year old shift fork? Or, does this point to some other problem that I need to look into. I have no idea....but it was functioning and engaging 2hi, 4hi & 4lo. It was always a bit tough to shift but I always chalked that up to age.

 

[Viperwolf1]

Tough to see in the pics. If the fork is loose on the rail it will wear the tips at an angle because the fork gets cocked between the rail and the gear. Might also get some wear marks on the side of the fork near the casting numbers. See the pics below. I didn't reuse this fork.

 

[mattt]

It's worn evenly across the fork. Where it is worn is the flared out foot on one side of the fork. It was not loose on the rail. The raised foot is there on one side, but worn away on the other side. The foot on each side is what fits in the groove on the sliding gear.

 

[Viperwolf1]

I see what you mean. Maybe the shifter was out of adjustment and it was putting pressure on the rail and fork. It doesn't look all that bad though. I'd use that fork in the front drive side probably. It should see less wear there.

 

[1970mule]

Good thread! I have a 1970 with a T-shifter. How much easier will it be to shift in four wheel drive with the twin stick (without the internal changes)? Thanks

very easy, and you can tell exactly what range your in all the time, easy good mood to do.

 

[Viperwolf1]

I see what you mean. Maybe the shifter was out of adjustment and it was putting pressure on the rail and fork. It doesn't look all that bad though. I'd use that fork in the front drive side probably. It should see less wear there.

With the additional pictures it looks worse than I thought. Now I'd replace it. That's the kind of thing that happens when people use bungie cords to keep a transfer case from popping out of gear.

 

[mattt]

Picked up some good set screws, and a good used shift fork. Starting to slap this thing back together.

Is the "Dana 20 Manual" that is referenced in multiple threads here just gone...dead? Every link I click is dead. Thanks in advance.

 

[Pa PITT]

Matt I'm going to go look in my shop to see if ''You've stolen my Bronco'' Mine's Name is ''Snakebite'' and every thing I do to it goes like your Transfer case job has gone ..
...I didn't do the rails in mine because I felt it would go like yours is..
...Good Luck on finishing it up..
............................................
..Running Buddy added his JB twin sticks ..his is hard to gear out of 4 wheel drive at times .. He thinks it in the shifters and trans fer case.. I say it's in his locking hubs.. Can't get the hubs to unlock .

 

[Dbarnes72]

Picked up some good set screws, and a good used shift fork. Starting to slap this thing back together.

Is the "Dana 20 Manual" that is referenced in multiple threads here just gone...dead? Every link I click is dead. Thanks in advance.

I think I've got the thread saved as a webpage. Shoot me an e-mail at darrellbarnes@yahoo.com if yu want and I'll ship it back to you. Doesn't seem to want to drop on a message so will have to do it the hard way.

 

[mattt]

The saga continues Papitt....you might have a point! Have it all put back together, and something strange is puzzling me. There is one way I can hit rear low(shift rail all the way in) and front high(shift rail all the way out).
If I start with both front and rear in neutral and engage front high, the rear will NOT go into low, However, if I have both front and rear in low range, and say I want to disengage the front.....the front will go into neutral....but will also continue up to high range.

I didn't remove the pills. I ground the rear shift rail as detailed in the link I posted previously. From what I saw in the write up there was no mod/grinding to the front shift rail. All I can assume is that I ground a bit too far?????? This is the only cross up combination I can come up with. No other bad combo will engage.

One other thing I notice is how easily(little push/pull effort) the front shift rail shifts vs. the rear. The rear takes a harder pull/push to change gears. Is that normal operation?

As far done as I am with this....I don't think another tear down is in the cards right now. Guess I will just have to be careful. Is there something obvious I'm missing....or am I not shifting as it will shift once installed in the Bronco?

 

[Viperwolf1]

Sounds like you might have ground a little too much. The springs and balls put the tension on the rails. I always recommend replacing them during a rebuild because they'll lose tension afte so many heating/cooling cycles. You can also shim the spring with a small washer. The front side is easy to get to underneath.

 

[bronco-billy-66]

How big does the hole have to be for twin sticks with a 1inch BL? Got pics?

 

[mattt]

Sounds like you might have ground a little too much. The springs and balls put the tension on the rails. I always recommend replacing them during a rebuild because they'll lose tension afte so many heating/cooling cycles. You can also shim the spring with a small washer. The front side is easy to get to underneath.

Or not........I had a conversation with Jack O'Brien recently about low gears and all things Dana 20. After speaking with him for at least 1/2 hour on the phone(very generous with his time to say the least), I am referring to him as Mr. Dana 20. He knows them backwards and forward. I say that for one big reason.....we were discussing twin stick and the shift rail grinding mod......he interjected and said...."Be careful, you may find one combo of Hi-Lo that will engage when you do this modification."

He nailed it without my mentioning or explaining what mine is doing. He basically said that as these cases age, the minute(sp) wear on various items will allow the Hi-Lo
engagement. He chalks it up to wear in the shift rail bores in the case, wear on the interlock pills, detent balls, springs, the shift rails themselves and any combo of the above. He said most of it is from case bore wear that allows the shift rails to slightly deflect and engage Hi-Lo.

We also discussed the wear on the rear shift fork that is shown in a pic I posted further up in this thread. He attributes that to a design flaw that over 40+ years will rear it's head. He then said to not throw away the worn shift fork as they are no longer made so he re-conditions them to new spec.

He now offers for sale...new shift rails(modified or stock), new detent balls and springs with more tension, low range gears, HD rear outputs, and pretty much anything else you'd want to upgrade your Dana 20.

I found my discussion with him very informative, a bit relieving(that I didn't do something wrong when grinding the rail), and educational in all things Dana 20.

 

[MTBronc]

very easy, and you can tell exactly what range your in all the time, easy good mood to do.

To do this conversion, what does a guy need to buy? I just bought a '70 without a twin stick and want to install one but I am a total newbie to EB's. What advantages and disadvantgages come out of just installing the twin sticks?

 

[cougarmandan]

Where does a person buy the new shift rails at? I got a twin stick to go into the T-shift and I have pretty much the whole EB apart right now so I haven't got to tranny/transfer case.

Also, on a side note, I saw some twin stick knobs that that had the Bronco logo on them as well as the shift patterns a while back and I for the life of me can't locate them on the net. Anyone know where I saw them at?