dana 20 twin stick

juggernaught

I was just informed by the shop rebuilding my '76 vintage dana 20 transfer case that they really did nit want to twin stick my transfer because they new of too many that "jumped" out of low range under load. How many other members have had or seen this problem? Is there a standard "fix"?

tufcj

The only ones I've seen jump out are improperly done. They need to add a detent in the shift rail that is the correct position and shape. Personally, I've never twin sticked a 20, but did the research. I'm running a twin stick 300, and could never go back to single. Bob tufcj

juggernaught

I'm not quite sure what a "detent" is. I have been told by several sources that it is not uncommon for a D20 twin stick to "pop out" under a load in LOW. Partially due to the fact that only one spring and ball assembly is now holding that shift rail in gear. My 4x4 mechanic is very knowledgeable and I respect his opinion on this upgrade. I will be calling the venders on any upgrades necessary to help with this issue, but would like to here some forst hand reports from dana 20 users.

juggernaught

Just did a google of "d20 rail shift mods." and found a wealth of info.......mostly on broncos d20 apps. Also found shift rail "fixes" and after market options via NOVAK ADAPTERS. After all the reading I would not attempt twin stick change over without some alterations/replacement of my rails. Any other input would be greatly appreciated.

juggernaught

One last question......with a locker (or posi), installed in the front axle, It would seem that even if you disengage the front drive shaft (via a twin stick set-up), you would still get the "binding" associated with a "locked" diff. as you turn the steering wheel in a tight circle, because the diff. is still "locked". The only way I can see there not being this increased "binding", would be because there is no power/torque being applied to the front axle. Am I thinking straight? I presently have a posi. up front and would like to replace it some day with a locker. My main reason for installing a twin stick set-up would be the advantage of keeping my hubs engaged while being able to shift in and out of four wheel drive. But, I want to be sure that when I diengage the front axle that It will feel like I am driving an "open" diff. with no steering "pull". Please enlighten me.

msalaba

Just to help others looking at this:

msalaba wrote
Full Dana 20 Manual

http://www.azbronco.com/dana20.htm

Pic of factory rail assembly

Pic of the D20 Shift Rail Mod

The grinding for the interlock pills is only required if you use the pills to keep you from shifting front low/rear high or vice versa.

If you leave the pills out, you can shift front and rear in opposite ranges for a redneck parking brake.

Most important is the long ramp on the rear shift rail. This needs to be built up with weld and then ground down to a nice U shape as seen opposite on the front shift rail. This prevents the t-case from walking out of rear low.

Like to mod writeup: http://www.wt4x4.net/tech/twinstick.htm

These pics are of a Bronco D20. After looking at my Jeep TSM, the front bearing retainer is different. On the Jeep, the shift rails go throught the front bearing retainer. The Bronco shift detent balls are on the side of the shift rail while they are on the bottom on the Jeep app. There is a plug on top of the front bearing retainer where the shift rail goes through. The spring and detent ball are inserted through this hole and held down as the shift rail is inserted. This difference is quite apparent if you have your t-case apart and look at it.

This means the detents on the shift rail in the above pic will be on the bottom for the Jeep instead of on the side as displayed.

dan58

juggernaught wrote
I presently have a posi. up front and would like to replace it some day with a locker. My main reason for installing a twin stick set-up would be the advantage of keeping my hubs engaged while being able to shift in and out of four wheel drive. But, I want to be sure that when I diengage the front axle that It will feel like I am driving an "open" diff. with no steering "pull". Please enlighten me.

No worries at all. A locker will only engage when under power (meaning when you are in 4wd). Same as TJ/YJs. That's how a locker is meant to work. A front locker is one of the best mods you can do.

msalaba

juggernaught wrote
One last question......with a locker (or posi), installed in the front axle, It would seem that even if you disengage the front drive shaft (via a twin stick set-up), you would still get the "binding" associated with a "locked" diff. as you turn the steering wheel in a tight circle, because the diff. is still "locked".

The only way I can see there not being this increased "binding", would be because there is no power/torque being applied to the front axle. Am I thinking straight?

I presently have a posi. up front and would like to replace it some day with a locker. My main reason for installing a twin stick set-up would be the advantage of keeping my hubs engaged while being able to shift in and out of four wheel drive. But, I want to be sure that when I diengage the front axle that It will feel like I am driving an "open" diff. with no steering "pull". Please enlighten me.

I have a liconln locker in the rear and have run a few different setups up front.

I started with a spool and steering was horrible whether the front was engaged or not. I have read some who have had success running a locker in the rear and spool up front. I have not tried this so I can't comment.

Next I ran a Lockright. Steering was great. The locker had a bad habit of unlocking when you didn't want it to and locking back in when it shouldn't. Unit may have been defective but I was not happy with it.

I now run a Detroit and wonder how I went so long without it. Steering does not make any difference 4WD or 2WD. I'm spooled in the rear and that is noticable. (pushes bad) When the wallet allows, a Detroit will go in the rear.

My cousin runs Detroits front and rear in his CJ7 on 35s. (stock axles D30/AMC20) 2WD or 4WD you'd never know the lockers are in there. He can drive circles around me.

For a DD running Detroits, make sure the front hubs are disengaged on the street. Saves wear and tear.

Hope that helps....

tufcj

I'm running Dana 44s with Detroit Lockers front and rear in my CJ. That's why I went with the twin stick on the 300. It lets me unlock the front even in LO range. On mine, there's a huge difference in turning radius when unlocked vs. locked. I only use the front when necessary. It's amazing how far you can go with just a locked rear axle. When I need the front, it's a simple click of one stick. Driving on the street with the front locked is a handful. It tries to change lanes with every throttle change or shift. I only drive the Jeep in the absolute worst snowstorms because of that. Bob tufcj

juggernaught

Thanks guys. That is exactly what I needed to know. Looks like the twin stick will work great for me. My transfer will be rebuilt with a dana low and twin stick installed shortly.Can hardly wait to get my rebuilt 360 and tranny mated so I can get back on the trail. Everyones in help is greatly appreciated.

juggernaught

Latest report........I went with a twin stick set up made by Don's Twin Stick, only because we guaranteed it woud not jump out of gear (He has since sold out and retired). I am very happy with the T/S setup, which I topped with a set of labeled, billet shift knobs by JB Ent. The shift pattern is now reversed and has a very "positive" feel. I can still feel the front posi in my steering, but it does not "load up" as much as it did under power. Novak may be marketing a similar set up, but I would not purchase anything if it was not fully guaranteed to stay locked in gear.