gonna swap a cab/chassis 80 for my 70

gonna run srw just want the strongest possible ...

how much do you have to cut from the driveshaft?

any other advice would be appreciated

thanks

 

2broke2smoke, putting a Dana80 in replace of the Dana70 seems almost overkill.

According to Dana the Dana70B is rated to 7500#, the Dana 70 HD is rated to 10,000# and the DanaHD/OS is rated to 10,000# also. Can you check your diff tag to see which you have?

Do you have disc brakes? They seem to say the 70B only comes with drums (?) but not sure how much truth there is to that.

Check out the Dana PDF... dunno if our axles are the "off road" version.

http://xj.cdevco.net/auto/pdfs/

 

i've looked all over for that pdf

i've got drums on mine

i'm thinkin' of pullin or draggin

it's my understanding that the 70 pinion is a little fragile at 500 hp

i'm gettin' a good deal on a brand new 80, yep never in a truck

and my 70 is perfect right now so it's a good time to swap 'er out

p.s. i was born in Trenton ... got out young though

 

If your 70 rear is a 3.55 with limited slip, do you want to sell the center section?

 

i'm gonna trade the 70 for the 80

 

So my 2001.5 with disc has the 606708-4, wonder if it is a 70HD or some sort of lesser 70 that Dodge/Dana dreamed up. SNOKING

 

Any info on the diff tag ? I tossed mine out because I know what it is (whoops).

 

Yes 606708-4 and 52069471AL.

Found similar numbers as the 606708 on a DANA list, but not that one.

Knowing DC!!!???? It may not be the 70HD!

SNOKING

 

Found a web site that says it is a 70U in 2001 Dodge.

http://www.drivetrainsuperstores.com/default.asp

Put the 606708 number in.
606708
DANA 70U REAR

--------------------------------------------------------------------------------
Year 2001
Make DODGE
Model W2500
Number of axle splines: 32 FULL


DANA 70U REAR AXLE - 32 SPLINE

--------------------------------------------------------------------------------
(STANDARD-pinion) REAR
Number of cover bolts: 10
Number of axle splines: 32
Diameter of ring gear: 10.5"
Number of ring gear bolts: 12
Pinion Shaft Diameter: 1.75"
Pinion Splines : 29
Low Case Ratio : 4.56


SNOKING

 

To my knowledge, you have what is commonly referred to as a 70/80 hybrid.......this amounts to a D70 HD which is actually a D70 ring and pinion with a D80 sized carrier bearings and carrier..........you will get the larger carrier and it's internals which bring potentially increased capacity for the assembly to carry more weight but that is about it, IMO........you are still stuck with the small pinion and it's bearings (pinion and bearings are the same size as a D60) that are marginal at best for pushing big torque as you already mentioned............for making big power there is no substitute for the much stronger D80 pinion........the way to go, IMO

 

exactly what i thought

 

I swapped a D80 into my truck and had NO driveline modifications. It bolted right up. My truc is also lifted so if the driveline is a little too long, for the 80, it may just be ok with a lift but the ujoint is the same.

 

cab and chassis 80 is 2 inches THINNER ... ie; tires sit inboard 1 inch on each side

looks geeky with the 265's ... but with a set of 33x12.50's ... they will be tucked nicely under the fenders

looks like it would high center on a pop can with that big diff and little weeny 265's

strength not looks are my motto anyway (ever seen a 289lb registered nurse )