Dana 20 help

[AV67]

So the Rubicon made me pay this trip, I lost low range about an hour into it and now I have to decide to rebuild the Dana 20 again or pull the trigger on an Atlas

Any recommendations on someone to rebuild the Dana 20 in the Brentwood area

If anyone is running an Atlas II or 4 speed let me know your thoughts

The Dana 20 already was re-geared with the Terra Low 3:15 gears and the advance adapters output shaft about 3 years ago, I haven't taken it apart yet but its still drivable in high range

I want to get lower gearing so I was thinking of going the doubler route behind the Dana 20 if I rebuild it again

I am running a 351W with a NP435

Any thoughts would help

[welndmn]

Re: Dana 20 help

I can either give you a hand rebuilding it, or you can drop if off and pay for some labor, they are very easy to do.
I've seen those Tera low gears go bad before, and if that's your problem, your need to buy a 2nd set.
Swapping out to an atlas might be a better option if you want to keep the lower gears.

If you want something right away, I have a spare t shift I could loan you, it's bone stock and worked 5-7 years ago when it was pulled.

[dblue351]

Re: Dana 20 help

Well I have the atlas 4.3 with a 351W and 435 and i will tell ya it was the greatest thing i ever bought for my Bronco!

[AV67]

Re: Dana 20 help

Mark thanks for the offers and I may have to take you up on one, which version of the STAK did you use?

Thanks DBlue351 I was looking at either the 4.3 or 5.0 myself

Does anyone know if the Atlas 4spd fits between the frame rails or does the frame need to be modified

After looking at the STAK and Atlas web sites I like the idea of more gear options

[NorcalKD]

Re: Dana 20 help

I have the Atlas 4speed 10.34:1. As DBlue351 said, it was the best thing I bought for my bronco. But like all of the Atlas t-cases they are not able to be clocked completely flat between the frame rails without notching the drivers side. I believe you can go into DBlue351 build to see how he did his, I have not done it yet.

[welndmn]

Re: Dana 20 help

I have the Stak mini monster 3 speed, I'd not buy it again, it's just not an Atlas.

[AV67]

Re: Dana 20 help

Is the Stak Monster B Box the same as the mini? this morning I convinced myself to go with the Stak Monster B box 3spd, what don't you like about the Stak box

[dblue351]

Re: Dana 20 help

Yes it took some modifying to fit it flat.

[welndmn]

Re: Dana 20 help

The b box is the not the same as the mini, to me the B box looks like a v drive setup that hangs down very far.
The reason I'd not deal with the stak is mainly mine is WAY louder than an atlas, with no windshield and large tires, I can still hear the gear whine.
Dealing with Stak is near impossible as well.
Buy the Atlas

[AV67]

Re: Dana 20 help

thanks guys now I am leaning Atlas 4spd, worst case I could install it to clear the frame and see how that works and do the frame mods later when I kick myself for not having done the frame mods right from the get go

[AV67]

Re: Dana 20 help

Anybody have any pros or cons on the 11.70 or 10.34 to 1 version of the 4 speed Atlas case

[NorcalKD]

Re: Dana 20 help

Anybody have any pros or cons on the 11.70 or 10.34 to 1 version of the 4 speed Atlas case

The only con I have about my atlas 4spd 10.34:1 is that you can't clock it up above the frame rails without notching the frame rail. After having it for a few years, I think the 2speed is perfectly fine to get, the 10:1 is retarded slow, almost too slow, and I used to have only 4.10 gears now I will have 5.38's.

One of the advantages though about the 4speed is leaving the tcase in high range, use just the doubler, or of course putting the tcase in low and when you want to go stupid slow put the doubler down in low.

[pippinmader]

Re: Dana 20 help

The 4 speed atlas is very cool, there are a couple things to keep in mind. It is long, your 435 can be setup to be fairly short, depending on the stub shaft design, but you do want to keep your rear drive line angle in mind.
The other issue has to do with the kind of off-roading you do, if you only rock crawl then you are good to go, but if you do snow, mud, or sand you can end up with gears that are too low. I know it sounds crazy but it can be awkward, the problem isn't usually in forward gears because you have lots of choices, the problem is in reverse where you only have one reverse per range. For example if you are in low-low your reverse gear ratio (with 4.56 gears) is about 300, which is slow but acceptable for rocks, but not useful in other conditions where wheel speed is useful. Of course the 4 speed has a 2.72 option which might be about right for general off roading. The other option is to run higher gears in your axles, but then you put a lot of stress on your drive shafts and motor mounts. Maybe this is a long way of saying you should consider your reverse gearing and go with the higher geared (10.34) atlas.

[AV67]

Re: Dana 20 help

I was looking at a gear calculator and it looks like the Atlas 4sp will give me gear ranges slightly higher than my current low range, one about 30 points lower than my current low range and one crazy lower than what I have now

I hate to say it but this is the web page I use for the gear calculator

http://www.grimmjeeper.com/gears.html

[AV67]

Re: Dana 20 help

NorcalKD how much of a lift are you running? and did you have any drive line angle issues
I have a 5 1/2 lift and don't have any trouble with the front drive line so I am hoping the rear drive line doesn't get any shorter than the front