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Dana 30 Question.


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I've searched and scrounged and read a bunch, but when I try to find a limited slip for 3.55 gears on the D30 I run into some conflicting information.

The basics of the story are.  I have a set of Moog "upcountry" CC782 springs on the way to use with my spacers along with some chevy drop shackles.  My plan is to run 31" tires, but I need to re-gear.  3.55's with the manual transmission are looking like the right gears for me.  I would be right at about 1900rpm at 60mph, which is much better than the 1700 I currently sit at with my 3.07's and 235/75-15 tires.

So, my plan is to either grab a ford 8.8, or maybe an 8.25 Chrysler with 3.55 gears already in it. and a 3.55 geared D30 front from an XJ at the yard that I can also build up a little.  I want to at least brace the C's and maybe do a truss or inner sleeves.  Not really necessary for 31's, but I have always liked a little overkill.

Now, the real issue is.  i want to run some sort of limited slip at each end, ideally truetrac diffs.  Whenever I search for limited slips I get conflicting information on what gear types can be used.  They either say 3.73 and up only, which basically eliminates my options for an LSD, or that any ratio can be used.  

Can somebody clarify this?  I'm scratching my head, and not able to really find a solid answer.

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I strongly suggest you look into the Volvo LSD swap.

 

Long story short, Volvo 740s and 240s used the Dana 30 as a rear axle and some came with a gear driven LSD (torsen, I think). It is a 99% direct swap, the only thing that must be done is shorten one of the axle shafts, I don't remember which one, by 3/8th of an inch.

 

YouTube has a great 3 part series explaining all of it.

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I strongly suggest you look into the Volvo LSD swap.

 

Long story short, Volvo 740s and 240s used the Dana 30 as a rear axle and some came with a gear driven LSD (torsen, I think). It is a 99% direct swap, the only thing that must be done is shorten one of the axle shafts, I don't remember which one, by 3/8th of an inch.

 

YouTube has a great 3 part series explaining all of it.

Oh, I may look into that option.  Old Volvos are fairly easy to find at the yards here.  I would prefer something a little more bolt in, but affordable options are always welcome.

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The D30 has a carrier break ... So uses two carriers depending on gear choice.

3.73 and up use one carrier, and for lower (numerically) there is another carrier.

The only difference between the two is the spacing of the ring gear in relation to the pinion.

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http://www.rustysoffroad.com/jeep-driveline-driveshaft/jeep-lockers-arb-air-lockers-lock-right-detroit/detroit-locker-truetrac/detroit-truetrac-model-30-3-54-down.html 

 

http://www.summitracing.com/parts/dtl-912a584/overview/

 

Over a dozen options simply by typing in "Dana 30 TrueTrac" in Google and knowing the gear ratio to pick between the offerings.  Who woulda thunk it?  :doh:

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http://www.rustysoffroad.com/jeep-driveline-driveshaft/jeep-lockers-arb-air-lockers-lock-right-detroit/detroit-locker-truetrac/detroit-truetrac-model-30-3-54-down.html 

 

http://www.summitracing.com/parts/dtl-912a584/overview/

 

Over a dozen options simply by typing in "Dana 30 TrueTrac" in Google and knowing the gear ratio to pick between the offerings.  Who woulda thunk it?  :doh:

Yea, ended up finding the one on summit.  Whenever I tried searching Dana 30 Limited Slip, I just got 3.73 and up or Dana 44 30 Spline diffs.   I will be the first to admit that I suck at Google  :hmm: 

 

What I don't get is the price difference between the 3.54 and down and 3.73 and up.  It's over $100 more for the 3.54 and down carrier.

 

Now, with the true trac side covered, I did mention other limited slip types as well.  :doh:

 

P.S.  your rusty's link doesn't work for me for some reason

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The majority of d30's seem to have come with 3.73's or at least people wanting to change them making the one you need less popular? Otherwise yeah it makes no sense for the same basic part? Good luck

I chalk it up to demand.  Most people won't buy a diff for 3.55's, because most people aspire to more than 31's or don't care about on-road manners as much.

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