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The front differential

posted Dec 27, 2011, 12:21 PM by roehricht@bellsouth.net   [ updated Feb 11, 2014, 12:19 PM ]
I got this heavy duty Dana 44 with the flat top knuckles and steering damper out of a '75 K20 pickup that belonged to my little brother. He did one of those "Fall Guy" endo's and demolished the old rust bucket, but the front end was not damaged. Then it was parked for about ten years and received some water damage.
 
We , my son and I, disassembled it and began rescue and restoration on it a couple of weeks ago. The rotors and calipers were shot and all of the seals and bearings needed to be replaced. I've got the new parts and some special equipment to build this into a super strong dually style unit.
 
We have the original Spicer locking hubs to replace the old full time flanges. This was an external flange setup so the original locking hub option was massive. They were available for both GM and Ford Dana HD vehicles and some Jeeps as well. You can tell the intended manufacturer by the color of the plastic hub centers, red for Ford and blue or gold for GM and Jeep. That's the only difference. Otherwise they are identical.
 
We're changing gear ratios and wouldn't you know it, the carrier has to be changed 'cause the line of demarkation is 3.92:1 down and 4.10:1  up. The original ratio is 4.88 and I'm wanting 3.73, so a new carrier had to be found. Fortunately Dana has everything you'll ever need for this differential and a complete carrier with bearings and shims as well as spiders, axle gears, center pin, and even ring gear bolts was delivered to my door the next day, and for a very reasonable fee. Ring and pinion setup is a job for experienced mechanics and I've done it for racing operations for years. I won't get into the "how to" on this here. If you know how, you know what I'm saying. If you don't, find somebody that does and if he will, let him show you on your unit.
 
I'm making this a dually, so the front hubs have to be offset to the outside to acommodate (sp?) the backspacing of the dually style wheel.  I found a guy who makes these really great adapters. They're really stout and come with all the attaching hardware. Groeske is the name of the outfit, I finally  looked it up and added it to the blog. 
 
While disassembling the hubs and spindles we encountered some serious issues as far as seized parts and pieces. We had to remove the spindles with a hammer and chisel. You must use real caution not to damage them, but patience will serve you well, (along with penetrating oil and a good aim with the hammer)! Much cleaning and some prudent touchup with file and sand paper, ( those three inch Scotchbrite pads on a die grinder work really well ) will salvage a really bad part.
 
Test fit everything many times. Those big locking hubs interfered with the dually adapters, so the end caps had to be modified, (ground down) to clear the inside of the adapters. If you have access to a lathe or know a machine shop that will do custom work it can be done easily. I have lots of spare time and I'm good with hand tools so I just got out a small grinder and chucked them up in a vise. About a half hour is all it took and they look great and fit perfectly. 
 
So now I've got it all ready to put back together, and as I do it I'll add more pictures.
 
I've added a number of pictures of parts and sub assemblies. My son reminds me that some may not be familiar with these parts, their operation or their relationship to each other. As I learn how to edit and organize the pictures I'll try to add captions and or thumbnail descriptions.  I'll also try to enlarge some of the pics as well.
 
All we lack as far as the rebuild is the differential cover, some paint and welding the new spring perches in place, not necessarily in that order.
 
As I said on the wheel page, I've been attending to other matters and more urgent projects.  The front axle assembly is all but ready to install, but I'll have to wait 'til I undergo a little back surgery before tackling it. I have gathered a few more important pieces to make the whole settup work better, and the engine parts are slowly gathering in a spare room of the house.
 
Feb 2014
 
Been a while. The surgery went well, but other things have demanded my undevided attention.  I got the spring perches installed and discovered that the new passenger side perch is right up against the old perch that's cast into the center differential housing. So close in fact, that I'll have to use one 1/2" larger spring U-bolt and thus the GM cast iron spring clamp plates. So I orderd the plates off of Evil-bay and they arrived in just two days and for under $40.00. Good deal! I also found that the new perch on the driver's side is right over the mount for the stabiliser, oddly, right where the outside U-bolt has to pass THROUGH the bracket. Fortunately there's room to put a hole in the bracket and still have a place to mount the stabiliser shock.
 
My son and I did the final assembly of the adapters, the brake rotors, and even test fit a set of wheels and tires, (pictures to be uploaded in a few days). It all looks good except for a final touch up on all of the paint. Other pieces and parts are starting to come together, and we may put the front end together under the truck in a day or two.  I got the new U-bolts and spring center (tie) bolts and new hardware all collected.
 
 
 
ċ
roehricht@bellsouth.net,
Feb 26, 2012, 10:48 AM
ċ
roehricht@bellsouth.net,
Feb 26, 2012, 2:13 PM
ċ
roehricht@bellsouth.net,
Mar 1, 2012, 5:58 PM
ċ
roehricht@bellsouth.net,
Feb 26, 2012, 10:48 AM
ċ
roehricht@bellsouth.net,
Feb 26, 2012, 10:49 AM
ċ
roehricht@bellsouth.net,
Feb 26, 2012, 10:51 AM
ċ
roehricht@bellsouth.net,
Mar 1, 2012, 5:58 PM
ċ
roehricht@bellsouth.net,
Feb 26, 2012, 11:47 AM
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roehricht@bellsouth.net,
Mar 1, 2012, 6:01 PM
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roehricht@bellsouth.net,
Mar 1, 2012, 5:57 PM
ċ
roehricht@bellsouth.net,
Feb 26, 2012, 10:49 AM
ċ
roehricht@bellsouth.net,
Feb 26, 2012, 10:50 AM
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roehricht@bellsouth.net,
Mar 1, 2012, 5:59 PM
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roehricht@bellsouth.net,
Feb 26, 2012, 10:51 AM
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