for Christmas gift my wife got me an original service manual. I wonder if it has a section of how to disassemble and reassemble the rearend
I’ll share my own experience with the service manual, but keep in mind that the electronic version I currently have in my possession may be quite different from what you received for Christmas.
The 2010 service manual I was gifted a few years back from another Viper owner has a pretty comprehensive section on servicing the differential. For the most part, provided you had enough experience, you could muddle your way through a differential rebuild, but it is missing some key pieces of information that only experience can possibly fill. There are also some procedures that are only possible with the full set of factory service tools, many of which are either not available or are so prohibitively expensive that puts it beyond the reach of your average shade tree mechanic.
On the positive side, it is a highly useful reference for the various specifications (torque specs, backlash tolerance, etc.):
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It also has a comprehensive list of different special service tools, including drawings and part numbers:
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The part numbers are the most useful, as some of these can still be found on Ebay, some more loved than others.
There are, of course, limitations to the information provided. As one example, this is how they suggest removing the inner pinion bearing using the OEM recommended tools:
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A quick Google search found the Puller Press (C-293-PA) for anywhere from $319 ($249 + $70 shipping on Ebay) to $498.96 (Mopar Essential Tools and Service Equipment). The Puller Block Set/Adapters (C-293-47) were slightly more reasonable at $97.98 (Ebay), but were out of stock on some other websites. They certainly appear to be the correct tools for the job, but there are more cost-effective options like a clamshell bearing puller that can do an equally good job at a much lower price point:
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As another example, this is how they recommend removing the output stub axle shaft seals:
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I was able to pick up the seal remover tool (7794A) for ~$90, but keep in mind that I already had a compatible slide hammer. Unfortunately, it looks like they have gone up in price significantly since. There is currently one on Ebay for $221.95 (OBO), but it has clearly been damaged. Regardless, that is the best tool for that specific job, but they leave out one critical piece of info: before going to town on the seal with a slide hammer, you first need to take a pair of heavy-duty diagonal cutting pliers (a.k.a. ***** or dikes) and snip the seal’s tension spring – otherwise, it is extremely difficult if not impossible to remove. This is where some experience is required to fill in the gaps.
There are plenty of useful diagrams:
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But there are also some things that you will likely never be able to use, like the pinion depth diagram and variance chart:
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That chart could be incredibly useful, but only if the variance is marked on your new ring and pinion set. None of the new-in-box ring and pinion sets I’ve received (3.73, 3.55, and a fresh set of OEM 3.07s) had this etched on them, so that is likely something you’ll never encounter again. That would likely have been common while these cars were still in production, but obviously that is no longer the case, so you’ll have to start from scratch when it comes to selecting a new pinion shim.
The manual does confess that it only has some general information, like for generating and reading gear contact patterns:
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Solely relying on those diagrams will only lead to serious confusion, especially if you don’t know that an ideal pattern for an OEM 2-cut gear set may actually look something like this (this was from a set of Dana Spicer 3.73s):
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One example where this “general information” could really bite you is with applying RTV silicone sealant to the differential cover:
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They are missing one critical piece of information in step 1 –
you also need to apply sealant to the tops of the carrier bearing caps, as it fills the small gap between the caps and the supports on the differential cover. Again, only experience (and a little RTV) would fill in that knowledge gap.
That said, I’d still rather have the service manual than not. You just have to keep in mind that it was written for the average service tech that will typically only do a full R&R with an already fully built replacement unit, or only have to do small things like replace the seals. Setting up a new ring and pinion would be beyond the abilities of most, as they would likely just reuse the old shims and assume that the differential case itself is what determines the correct shims rather than the ring and pinion set. In my limited experience, the individual ring and pinion sets will dictate the proper shims – the ones I’ve set up used vastly different shim thicknesses than what were originally there to get everything where it needed to be.
Your mileage may vary, but I hope that you’ll find at least some of this information useful.
