Rear diff options

Kevin 007

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What were the factory rear end options in 84? I have a Dana 70 with 3.54's and what acts like an open diff. Were any trucks offered with a limited slip? I have had many sterling 10.25 axles with limited slip and they were great. Is there a factory LS setup that I can toss in my 84? Or do I already have it but the clutches are worn out?
 

PwrSmoke

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Nothing wrong with the D70 and it has more aftermarket LSD and locker applications to choose from than the Sterling. Read the BOM number off the axle tube (right tube when facing the cover, there are usually two set of #s, the ) and I'll tell you whether it originally had an LSD or not. If it's a D70, and with 3.54 gears, it should have a BOM of 605208-1 (open) or 608208-2 (Powr-Lok). Anyway, post the number, I'll look it up and tell you what's there.
 

Black dawg

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from what I have seen of the powerlock, you would know it was in there even if it was pretty worn out.
 

PwrSmoke

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Many of the so-called "Pwr-Lok" of the mid '80s used in the big Danas was more a burly Trac-Lok with a two piece case similar to the older Pwr-Lok but it didn't have the ramping feature that a "true" Pwr-Lok has, so it's much less effective and will fade away like a Trac-Lok to almost total transparency when worn out. It's still four-pinion, though, so that's a good thing. Still, who knows what's in there now? Someday, if I don't decide to be buried in it, some new owner will find a Trutrac in my truck and be pleasantly surprised.
 

Kevin 007

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All I could see is 70-13U. Im gonna take a pressure washer to it to possibly uncover any other lettering.
 

PwrSmoke

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That's the model number, Dana 70U. Use sandpaper. If you don't find stampings where I mentioned, try the opposite tube or on the front side.
 

Black dawg

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Many of the so-called "Pwr-Lok" of the mid '80s used in the big Danas was more a burly Trac-Lok with a two piece case similar to the older Pwr-Lok but it didn't have the ramping feature that a "true" Pwr-Lok has, so it's much less effective and will fade away like a Trac-Lok to almost total transparency when worn out. It's still four-pinion, though, so that's a good thing. Still, who knows what's in there now? Someday, if I don't decide to be buried in it, some new owner will find a Trutrac in my truck and be pleasantly surprised.

Is there an easy way to tell one of the less effective ones from an earlier one? I have one removed from an 80s van that would chirp tires at times.
 

PwrSmoke

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Yes. If there are "v-notches" in the housing at the ends of the cross, and the ends of the crosses are correspondingly notched then it's a "true" Pwr-Lok. The top pic is a Pwr-Lok. I looked for a pic of the big Trac-Lok, but I couldn't fine one. It's a two piece case that looks a lot like a Powr-Lok but the ends of the crosses ae round and fully captures as you see in the pic of the Detroit locker. I didn't steal these pics off the internet by the way, I took them for a book I did for Randy's Ring and pinion called "Differentials."

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PS. There is one on sale on eBay with a pic, look http://www.ebay.com/itm/2011842-Dana-80-Trac-Lok-Posi-35-Spline-3-73-Down-/371143337022?pt=Motors_Car_Truck_Parts_Accessories&hash=item5669dde43e&vxp=mtr

Which do you have?
 
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Kevin 007

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Tried once more. I think I may have to take a sand blaster to the axle tube lol All I got was "5205" which was very legible. Then underneath that and upside down is "0261G" I will have to find a means of cleaning this up better...
 

riotwarrior

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K if the bottom of the unit is super smooth, like incredibly smooth and NO bumps just a nice slick bottom, it's likely a 70U rear diff.

If not it's likely a 60.

JM2CW...

Oh pics help cause the diff cover is same from 60-70 no matter both are same
 

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