[ROVERNET - UK] Rearend woes

Vern Klukas vern at inkspotco.com
Sat Oct 20 17:27:49 BST 2007

The diffs are generally very robust, I am a little surprised you are 
having troubles at less than 200,000 miles. Of course, if it has been 
run without oil at some point, all bets are off.

Several other things may be happening, so check that:

1. All the u-Joints are new, right? My point being that there are 6 
of them. The halfshaft ones in particular lead a tough life.

2. The rear mounting bracket mounts are sound and the bracket itself 
is not cracked.

3. Similarly, the panhard bar (the lateral bar running from the rear 
bracket to the base unit) bushings are sound

4. The forward dif mounts (3 on a 3500) are sound, these are often oil soaked.

If that all checks out, It may be internal to the diff, all but 
certainly the spider gears in the diff carrier itself. The crown 
wheel and pinion, unless the thing howls like a banshee, will not 
require replacement (thought there is a brand new set up on ebay 
right now, from Australia).

The other weak part of the diff are the stub axles, which crack over 
time at the splines and then shear. But they never give any warning, 
just a quiet bang and then a total loss of drive.

If you are not replacing the crown wheel and pinion, all the bearing 
can be renewed and the existing shims left, if you take care to match 
exactly the bearing dimensions (i.e. make sure the width of the 
bearing race is within say .0005" of the width of the old one). All 
bearing and seals are std sizes, and there are only a handful of 
gaskets, none of which are critical in thickness (as I recall, at 


>Well,  I've discovered that 180,000 miles tends to take its toll on one's
>rear (LOL).  After rebuilding the engine and trasnmission, the mechanic who
>rebuilt the transmission for me has confirmed that all of the 'clunking' I
>was so worried about with the transmisssion and downshift cable adjustment
>is really the differential on its way out.
>I would appreciate any words of wisdom before I begin pulling the
>differential out for a rebuild.  Since I was a virgin when I pulled the
>engine and transmission out and somehow figured out how to reinstall it and
>actually get it running, I'm hoping that with drawing the differential is
>actually somewhat simpler.
>Also, I've left a detailed message with Ruth at ABC about the potential need
>for parts (e.g., hypoid gear, differential gear, oil seals, etc.)----Anyone
>have any other resources for parts?  Is there such a thing as a diffrential
>rebuild kit?
>As always, any help from those in the know woulbe be much appreciate.
>Lance La Certe,  '70  'Federal' 3500S
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>rovernet at lyris.ccdata.com
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Vern Klukas                             I'm a little . . .
Inkspot Type & Design
vern at inkspotco.com

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