Beefing Up A Dana 80 Rear

RacinDuallie

Black Sheep Racing
Joined
Apr 24, 2006
Messages
17,382
I'd like to beef up my ol duallie rear assembly for my heavy foot and abuse that comes with it.

Any tips? It's a 4.10 gear with the 'Anti-Spin' diff. :1tooth:
 
Well Jeff, seeing as the 80 is pretty much bulletproof from the factory, why bother??? LOL

Seriously, about the only thing I can think to do is a stouter pinion shaft and maybe a set of axle shafts. The R&P seem to be pretty stout.
 
The weakest link in a Dana 80 is the spider gears.
They are the same size as used in the Dana 60 & 70.
With an 80 open carrier, you only have 2, and a limited slip, you have 4.
Dodge used 2 different types of limited slip units in the 80.
The Trac-Lok, and the Powr-Lok.
Comparing the 2 side by side, you would think the Trac-Lok would be the better of the 2 because of all the extra clutch plates and discs.
But unfortunatley, the way they are stacked defeates their purpose.
Starting with 5 plates, then 3 discs makes only 1 surface contact area between 8 of them, then alternatley stack the remaining few with 1 dished disc for preload.
The plates and discs are all flat and are not suppose to be restacked.

A Powr-Lok uses dished discs, flat plates, and use less per side.
They can be arranged for different preloads with instructions right out of a Dana manual.
Plus the spiders are mounted on a 2 piece cross shaft that allows them to add preload under torque, to apply extra pressure to the clutch pack, makeing them less likely to slip.
The Trac-Lok spiders are on a 1 piece fixed cross shaft, and cannot apply any extra pressure to the clutch packs.
The reason this is important is because any torque that is going through the spiders to the opposite side is what breaks them.
You want the clutches to take the torque load, and take it evenly, reduceing the strain on the spiders.

With that l o n g explaination out of the way, 90% of the Dana 80's have a Trac-Lok.
An upgrade would be to go to a Powr-Lok.
Or, depending on how the truck is used, go with a Detroit Locker.
No spider gears at all in a Detroit.

Another, but not as necessary, would be to go to 37 spline axles shafts.
Would really have to be under abuse to mod the shafts, but they do break.

Sorry for such a long post guys.
Hope this helps.

Brad
 
Sorry for the long post???? WTH you smokin!!!!! That's the kind of info these forums are about!!!!

I just learnt me som'thin :D

Thanks!!
 
B KIRK said:
The weakest link in a Dana 80 is the spider gears.
They are the same size as used in the Dana 60 & 70.
With an 80 open carrier, you only have 2, and a limited slip, you have 4.
Dodge used 2 different types of limited slip units in the 80.
The Trac-Lok, and the Powr-Lok.
Comparing the 2 side by side, you would think the Trac-Lok would be the better of the 2 because of all the extra clutch plates and discs.
But unfortunatley, the way they are stacked defeates their purpose.
Starting with 5 plates, then 3 discs makes only 1 surface contact area between 8 of them, then alternatley stack the remaining few with 1 dished disc for preload.
The plates and discs are all flat and are not suppose to be restacked.

A Powr-Lok uses dished discs, flat plates, and use less per side.
They can be arranged for different preloads with instructions right out of a Dana manual.
Plus the spiders are mounted on a 2 piece cross shaft that allows them to add preload under torque, to apply extra pressure to the clutch pack, makeing them less likely to slip.
The Trac-Lok spiders are on a 1 piece fixed cross shaft, and cannot apply any extra pressure to the clutch packs.
The reason this is important is because any torque that is going through the spiders to the opposite side is what breaks them.
You want the clutches to take the torque load, and take it evenly, reduceing the strain on the spiders.

With that l o n g explaination out of the way, 90% of the Dana 80's have a Trac-Lok.
An upgrade would be to go to a Powr-Lok.
Or, depending on how the truck is used, go with a Detroit Locker.
No spider gears at all in a Detroit.

Another, but not as necessary, would be to go to 37 spline axles shafts.
Would really have to be under abuse to mod the shafts, but they do break.

Sorry for such a long post guys.
Hope this helps.

Brad

SORRY FOR THE LONG POST!!! :dead-horse-fast2: That was a GREAT POST ! :woohoo: LOL Thanks for the entire reply! Twas very informative !


I'm liking the Detroit Locker set-up. And the beefier axleshafts. :woohoo:

I already have a BEEFIER 1pc. driveshaft w- larger u-joints that was swapped in place of the 2pc split sh** shaft that was there stock... I was going thru them bearings between the 2 shafts -fast:doh: . I think inpart due to alot of serious axle wrap. Since- I swapped to the BEEFY 1pc. deal it has been nite and day.:bow:

Also, I took the rear helper spring bumpstops off ( front pair ) and drilled and tapped and screwed in some old B-body Mopar Lower control arm rebound bushings in and remounted the bumpstops....:woohoo: cheapie pinion snubber- Problems solved totally.

The new and improved engine is almost ready to be dropped back in, I have about 103,000 on the truck and want to refresh the rear, The trans is a fairly fresh Full Metal Jacket SunCoast, and a fresh SunCoast 5 disc, I don't even think I have 5 thous miles on this trans -so that's pretty fresh yet.. Maybe look at the transfer case too while I'm at it.:ugh:

so this information is useful to me thanks for your reply!!
:ylsuper: :ylsuper:
 
Back
Top