>From: "Kyle Kozubal"
> A 'stock' Dana 60 has a 9.75" ring gear. The axle splines will vary from
30
> splines to 35 splines. A typical 30 splined Dana 60 can handle 6,200
pounds
> while a 35 splined Dana 60 can handle 9,600 pounds. Normal 30 splined Dana
> 60s have axle shafts which are 1 5/16 thick, while the HD 35 splined Dana
> 60s have a 1 1/2" axle shaft. They currently use Dana 60s on trucks with a
> gross weight rating over 16,000 pounds. Dakota are what.....like 4000-4500
> pounds?
Actually a small correction here..........................
Class is in session.
When an axle is rated in pounds, it does not mean the weight of the vehicle,
it means torque multiplication.
For example:
Let say you have a Dakota with a 408 that puts out 500 lbft of torque at
4000 rpm's, you are running a 5-speed, and have a 30 spline Dana 60 with a
4.11 gear in it.
Multiply Torque (500), by first gear ratio (3.35), and then by rear gear
ratio (4.11).
500 x 3.35 x 4.11 = 6884.25
That is 6884.25 lbft of torque to the axle. The 30 spline axle is rated at
6200 lbs, this is clearly not strong enough to withstand the torque, you
would need a 35 spline in that case. This is an extreme case but feasable
with pefect taction, or Matt. This is why many 8 1/4's break under 5-speeds
and work fine under automatics. An auto will pre load the axles and gently
launch, where a 5-speed will shock the axles and cause them to snap.
Mark Kuzia
flyboy01@mediaone.net
http://people.mw.mediaone.net/flyboy01/home.html
1995 Dakota 13.79 @ 102.45 mph
~360ci, 5-spd, 8 3/4 rear / 3.90-SG
1994 Dakota 15.36 @ 91.56 mph
~318ci, 5-spd, 3.90 LS (bone stock, no mods)
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