60 Big 35 Spline Inner and Stub Axle upgrade from 4WDFACTORY.com
The venerable Dana 60 front axle is a seriously beefy piece of kit for the hardcore wheeler. But like so many things, everything is not always what it seems, and everything has its weak points. This article is dedicated to illuminating, then eliminating the weak points of a stock Chevy Dana 60 front axle. For the purposes of this article, Dodge kingpin Dana 60 front axles will be identical.
I should make a small note here about my philosophy, as it will help to illuminate some of the points I will make. In building a rig, I do not believe in designing in a "weak link". It just makes no sense to me - not when I intend to fully explore the limits of man and machine when I go wheeling. What I want to be the "limit" is not a weak part, but rather the limit of traction (i.e. tires break free before anything breaks) or my courage / sense (I let off the throttle and/or try a different line before anything breaks). Of course, this may not be achievable - anything CAN break - but that is my philosophy. I want everything to be as strong as possible (within my economic realities) and in a reasonably balanced system (no point running 60 outers on a D30 front!). I find this to be particularly important when building an axle, as there are no really simple / cheap "fuses" to build in. If a u-joint breaks, it often destroys the shafts with it (or vice-versa) ; if a stub shaft goes, it often takes out the hub (lockout) and it can ruin/deform the spindle. In other words - breaking sucks. I want to build to wheel - not build to break.
So, what are the weak points of the Dana 60 front? The areas needing upgrading are:
Early "neck-down" inner 35 spline shafts - (breaking can shock-load and damage locker and/or opposite side axle)
Stock 30 spline stub shafts - (breaking usually destroys lockout, and can ruin the spindle)
Stock 30 spline lockout hubs
Stock 1480 series u-joint - (breaking usually deforms the ears on both inner and stub shafts)
35 Spline lockout hub.
The 1980 Chevy K30 1 ton 4x4 front dana 60 in my Wolf suffered from most of these weaknesses. I am presently running 39" Michelin military tires on some pretty rough terrain, and I plan on running 42" tires soon, so some beefing was in order.
I called up Greg at 4WDFACTORY.com. He is the man when it comes to Dana 60 parts and upgrades, and carries every part you might need to rebuild or upgrade your Dana 60. I settled on a complete 35 spline stub axle package with drive flanges, new "big" 1.5" 35 spline inner axles and a pair of kingpin rebuild kits. The kingpin rebuild I cover in a separate article you can read here. This article covers all the rest, in 5 parts:
Part 1 - Kit Contents
|All of the gear I ordered arrived in 2 large, heavy, well packaged boxes. Step one was to have "Bear" give it the old once-over to make sure everything looked good. She gave an enthusiastic "paws-up".|
|This box contained the stub axles, u-joints, Warn 35 spline drive flange kit, kingpin rebuild kits, stickers, and a Yukon catalogue.|
|This box contained the inner axle shafts. The shafts were wrapped in anti-corrosion paper, placed inside boxes, those boxes were surrounded by packing foam, and placed inside another box. Everything arrived in flawless condition - no shipping damage at all - and that's all the way from Texas to Nova Scotia! I've said it before many times - but I'm such a fan of well packaged goods.|
I almost shipped a little surprise back to Greg! Like I said, it was a pretty big box.
I should make a note here about Yukon, as there seems to exist great confusion as to how it works. Here is my understanding: Yukon does not "manufacture" anything per-se. They are a "buy in bulk and re-box" type of operation. This is actually very common in business, occurring even with many National "name-brand" products (but this isn't a marketing article so I'll try to keep this short). Essentially, what they (Yukon) do, is have agents that scour the planet looking for the best deals on bulk quantities of items - whether they be from discontinued items, stock over-runs, or just plain huge bulk orders. Because they have the capital to invest, they have huge "buying power", which means they can purchase for cheaper than others, and theoretically anyway, pass the savings on to you. Now, according to Yukon, they have strict quality control procedures, to ensure you always get the best product. I don't know exactly what their quality control is, so I can't comment on it. What I do know, is that I trust Dana/Spicer in the manufacture of gears and axles, and so that is what I wanted - Dana/Spicer. I communicated this to greg at 4WDFACTORY.com, and Dana/Spicer is exactly what I got - albeit in a Yukon box.
|Actually, the parts themselves came inside Dana/Spicer boxes that were inside the Yukon boxes. This box contains the long-side inner shaft.|
|This is the long-side inner shaft wrapped in its protective paper. It's also lying on the kitchen table - I have such a wonderful, understanding wife!|
|The wrapping is called ProtekWrap and contains Volatile Corrosion Inhibitors..|
|...whatever that means - it works, there wasn't a spot of rust on the shafts, despite the raw machined steel.|
Here's the contents of the 35 Spline upgrade "kit":
|35 Spline stub shafts (D70) Spicer part #: 3-82-871|
|Spicer "Life Series" greasable 1480 series u-joints, Spicer part #: 5-733X. This is the same as part # SPL55-4x|
|Warn 35 Spline Drive Flange kit, Warn part # 39346|
|This is the 35 spline stub shaft. It is HUGE compared to the stock 30 spline stub shaft, and should net an approximate 40% increase in strength over the old stub. This is calculated using the formula:Yield Torque (in/lb)= Tensile Strength (psi) x polar moment of inertia/ radius of material and assumes same material and heat treat|
The Spicer shafts are made from SAE1137 steel (not a true "alloy steel") and are induction hardened. In this pic you can clearly see the blue circles along the shaft that show the hardening.
From the "Machinery's Handbook":
"Induction hardening is done by placing the metal part inside or close to an "applicator" coil of one or more turns, through which alternating current is passed. The coil, formed to suit the general class of work to be heated, is usually made of copper tubing through which water is passed to prevent overheating of the coil itself. In most cases, the work piece is held either in a fixed position or is rotated slowly within or close to the applicator coil. Where the length of work is too great to permit heating in a fixed position, progressive heating may be employed. Thus, a rod or tube of steel may be fed through an applicator coil of one or more turns so that the heating zone travels progressively along the entire length of the work piece. "
In this pic you can clearly see the bluing that indicates the limit to the induction hardening of the Spicer shafts. the shaft is passed through the coil, and the coil has to be of a small enough diameter so that it is close enough to the shaft to do the heating, but that diameter prevents the passage of the yoke through the coil.
Some more pics of the stub shafts:
|This is the Spicer Life Series 1480 series u-joint in greasable version. The older part number is Spicer part #: 5-733X, which has been superceded by part # SPL55-4x. They are the exact same part. Some shops are referring to these u-joints as "snap-tight" because the new triple-locks seal is so good, the caps snap on really tightly. Indeed, when I installed the u-joints, I had to use channel-lock pliers to remove the bearing caps from the trunnions - I couldn't pull them off by hand - that's how good the seals are.|
A great deal has been made of these "new" style Spicer joints in the last year or so. You will often see them referred to as the "new forged' or "cold formed" u-joints. This is a bit of a misnomer, I think, because, as far as I know, Spicer u-joints have always been forged.
Spicer refers to them as the "Spicer Life" series. They do claim a 50% greater life due to the improved seal.
And they also mention "greater torque carrying capacity", but give no figures on this. The greater strength in part comes from the reduced diameter of the grease holes, as seen in this pic. manufacturing process, metallurgy, heat treating, and quality control procedures may all play a part as well.
Some conservative shade-tree estimates have been made at 20-30% strength increase over the old style u-joints. I personally have no idea if this is true or not, not having the equipment to run proper testing myself.
This is the contents of the Warn 35 Spline drive flange kit. When I spoke to Greg, I hemmed and hawed about whether to go with Warn 35 spline lockouts or drive flanges. On the one hand - the lockouts are nice because of the flexibility they offer, especially for a street driven or spooled front rig. On the other hand, the drive flanges are undeniably simpler and MUCH stronger.
In the end I went with simplistic and brute strength - was there ever really any question :-)
Whichever you decide, you do have to purchase new 35 spline lockouts or drive flanges, as your old 30 spline units will not fit on the new stub shafts.
If you have 30 spline drive flanges, you may be able to find a machine shop that can broach then to 35 spline for you.
The caps have a nice large o-ring seal, and secure with 3 simple Torx screws.
|The kit also comes with (L top R, top to bottom) large hub snap rings, cap screws with impregnated thread locking compound, cap retention plates (to which the caps secure- see installation later in article), 4 thrust/wear washers (2 for each side), and a pair of small stub shaft snap rings.|
|Close-up of the drive flange itself.|
|This shows one of my favourite parts of the kit. The Warn drive flange caps are VERY thin (that's a quarter in the picture), which means they stick out of the hub MUCH less than any manual lockout would, which saves them from abuse amongst the rocks.|
|The snap rings included are the "thin multi-wind" type. I much prefer these to the other type, because you can install and remove them without requiring snap ring pliers - just a small screwdriver will do.|
|Here are a couple of shots of the complete 35 spline stub axle upgrade kit.|
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