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January 2008 Dana 44 Putting it together with a Detroit Locker

• CATEGORIES: Biscuit, Features

With my Dana 44 all taken apart (See article below), it was time to put everything back together.  One aspect I have left out of the rebuild process is the importance I placed on using the appropriate language to assemble and disassemble the R&P properly; lets just say I'm glad my children weren't about.

Gathering tools and parts

In terms of parts, I needed to gather a rebuild kit, a locker, and axle kits.  Using Craigslist, I found a locker for 3:73 gearing locally for $325.  The rebuild kit I got at half price from a jeeper in Bend, Oregon. The axle bearings, cones, and outer seals were purchased online through Tellico4x4.com. The inner axle seals I purchased at Schucks. At first, when I realized I had forgotten to order these (oops), I went to tellico's website.  The seals themselves were around $5 a piece, but the cost for shipping was going to more than double the price.  I thought that was ridiculous.  So, I dropped by the local Schucks to see what it would cost to get the seals (I figured they would have to order them).  Well, to my surprise, they had them in stock! $10 later, I was out the door with them. 

There were some brake parts I wanted to replace as well.  For them I went to my local NAPA store where I got a great price on the slave cylinders and brake pads. 

For tools, I brought back my Dad's homemade hydraulic press and several different gear and bearing pullers.   In addition, I brought back my dad's big vice, the mother of all vices :-).  One final item I got was a parts washer that's still on loan (25 years and counting) from Jim Carter (Let me know if you need it Jim).  Getting access to the parts washer has been great, especially since I can run Simple Green in it rather than the horrible solvents I used to run in it.
Preparing Old bearings and Cones

NOTE:  SAVE YOUR OLD BEARINGS! 
Don't get all excited about getting everything apart then go on a cleaning binge prior to the rebuild and, during the cleaning, throw out the old carrier with the broken teeth and the old bearings; umm .. like I did. 

It turns out that the nice thing about the old pinion and carrier bearings and cones is that you can re-use them to estimate the proper shimming of both the carrier and the pinion.  While I did throw out the old carrier bearings, I saved the pinion bearings and cones.

HOW TO USE THEM.  Take your carrier bearings and hone out the inside of bearings so that they just barely slip onto your carrier.  It doesn't take much honing or grinding.  You'll save massive amounts of time not having to press the new bearings on with a press and pulling them off with a puller.  Do the same thing with the inside of the pinion bearings and the outside of the pinion cones. 

Installing — first round of measurements

Here's where the fun begins. 

THE GOALS:  In my case, for a dana 44, my goals were to snuggly install the new locker and the replacement ring and pinion into my old housing with 6mm – 10mm of backlash while getting the correct meshing between the carrier ring gear and the pinion gear. Also a must is the correct compression on pinion bearings (measured at roughly 20in lbs, which requires a special tool).For my first attempt, I tried using all the old shims from my old carrier and pinion in their previous places.  I slid the pinion together and tightened it. The pinion yoke spun freely indicating I would have to eventually reduce the shims.

After installing the good ring onto the locker and tightening the bolts with locktight to the corect specs, I pressed the new carrier bearings onto the locker (remember, I accidently threw out the old bearings .. sigh) and installed the locker into the housing. 

The next step was applying some "Non-Drying Prussian Blue" (yes, that's the name on the container) stuff to the gear to test the meshing.Unfortunately, the meshing was to far to the toe (inside) of the ring gear and to high on the crown (top) of the tooth.  You can see the results to the right.

Subsquent installs (bearings on and off, shims adjusted)

Since the gears didn't mesh using the original shims, I had to take everything apart and start making adjustments.

TIP:  I decided to use a permanent black marker to mark the thicknesses of my shims on the shims themselves.  I measured each shim carefully and wrote down the results on the shim.  This made tracking the changes and calulating adjustments to the shims much easier.

At first, I experimented mostly with shifting the carrier to the right and left.  This meant adding small millimeter changes to one side and subtracting it from the other.  I also made sure to increase the overall width so that the carrier fit snuggly into the housing. 

Each change meant I had to pull the bearings off the carrier.  This was one of my biggest challenges to solve, until I realized I had a bearing puller perfect for the job.  (I didn't realize I had the perfect tool until I went online to find a carrier bearing puller).  To make the bearing puller work, I had to slide a foot long 3/4" socket extension into the carrier center and then place the center of the bearing puller into that.  It wasn't an ideal solution, but it worked.

Getting the correct combination

I put a lot of miles on my garage floor, travelling between my computer, which showed the different gear meshings, and the housing, which was on the opposite side of the garage.  I'd put on the blue mesh stuff (I discovered the blade of a flat screw driver worked well for spreading the blue stuff onto the teeth), spin the gears, ponder the results, walk over to my computer, stare at the Gear Precision patterns and Mike's Dana 44 rebuild page 3, wander back to my housing, ask myself "does it look right", and, answering most times no, tear it all back down. 

I believe, based on my notes, it took 14 rebuilds to get it right.  At about rebuild 10 I finally realized the pinion needed to come forward towards the ring.  That's when I started having more success. 

At build 12 the mesh looked correct and the backlash was 8mm.  I felt great relief.  Now it was time to put the real bearings on the pinion (see pic to the right) and test it. 

Unfortunately, the new bearings on the pinion threw things off slightly.  The backlash was 15mm, though the meshing was good.  So, I shifted the carrier slightly to the right, which dropped it too much (6mm of backlash).  My final success was shims on the driver's side of the carrier of 44.5mm and on the passenger side 39mm, with a backlash of 10mm. The meshing appeared good across 2/3 of the tooth, though concentrated more towards the toe of the gear.  But, based on what I read in multple sources, that was acceptable.

NOTE:  In the beginning, I had started with 38mm and 35mm ‚Äî which wasn't too far off, but because I hadn't added more shims to bring the pinion forward, I wasted time shifting the carrier back and forth).  

Next steps

Now satisfied with my R&P specs, I needed to properly shim the R&P from the yoke side.  Rather than use a in/lbs torque wrench (which I didn't have), I chose to approximate it based on my front end.  After going back and forth between the two and making small changes in the front pinion shims, I was finally satisfied that the rebuild was complete.  WHEW!

Now, I just have to press on the bearings and retainers onto the axle shaft, complete the brake rebuilds, and I'll be able to throw the axle housings underneath the frame for the first time in a couple months.

Helpful Links for both taking apart and installing R&Ps

I had to stand on the shoulders of these giants to get this done:

    * Common Jeep Axle Specs
    * Installation Instructions Differential Ring and Pinion Sets
    * Precision Gear Patterns
    * Detailed installation instructions from Mike (lastname?)
    * R&P installation from offroaders.com
    * Locker install from BC4x4.com

 

One comment on “January 2008 Dana 44 Putting it together with a Detroit Locker

  1. Pingback: Specs of My Build | eWillys

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