Decided to DIY my diff -> 3.55 gears. Couple questions...

[cowger]

I'm getting ready to switch out my stock gearing for a 3.55 set this winter. A while back, I asked whether this was a reasonable DIY project or not, and I get it that most folks advised me at that time that this was something I should just take to a pro to do. I appreciate that input, and it's not a money issue, but I just really enjoy working on cars and this seems like a fun challenge to tackle.

Tools:
Here's the minimum I think I need:
- case spreader
- torque wrenches (both ft-lbs and in-lbs)
- dial indicator w/ mag base
- micrometer
- gear marking compound

From Harbor Freight:
- benchtop hydraulic press
- bearing splitter
- assorted bearing tools for pressing/removing the bearings

Parts:
- A high quality, OEM gear set, like from VPA
- New pinion oil seal
- New ring gear bolts (seems to come with most good gear sets)

I understand there are a lot more specialty tools made for this job, but most of them seem like they're used for accurately determining the running position of the pinion. I'm hoping that I can simply take the difference in numbers between the shim stack currently in there and what's stamped on the new set and get very close with that, and then verify by checking the mesh patterns.

I'm looking for some input on a couple questions I have before I get the car up on blocks:

1) I'm still searching for the correct manual for this... I believe that the Viper model is 44/216 -- is that correct? What's the Dana/Spicer manual number for this? Their website is a bit confusing with so many models...
2) Is my assumption on setting the pinion depth reasonable?
3) If there's nothing wrong with my current diff (30k miles), is it necessary to replace the bearings?


Thanks!
Bryan
'05 Black Vert

 

[JAY]

Great Post ! Looking to do mine eventually !

 

[cowger]

Great Post ! Looking to do mine eventually !

Thanks, Jay. If there's interest AND I'm able to convince myself that I know what I'm doing, I'll try to put together a thread for the Illustrated Upgrades section...

 

[JAY]

Thanks Cowger !

 

[Green viper 1]

Post lots of pics

 

[Tom Sessions]

"I understand there are a lot more specialty tools made for this job, but most of them seem like they're used for accurately determining the running position of the pinion. I'm hoping that I can simply take the difference in numbers between the shim stack currently in there and what's stamped on the new set and get very close with that, and then verify by checking the mesh patterns."


Good luck with this. Its not that easy. If you are working on the old farm truck that never sees hiway speeds then you might be Ok. Not so much with this application. Get the right tools and do it right the first time.

 

[cowger]

Good luck with this. Its not that easy. If you are working on the old farm truck that never sees hiway speeds then you might be Ok. Not so much with this application. Get the right tools and do it right the first time.

Thanks, Tom, and I'm happy to do so. Can you be more specific as to which tools you think I'm missing? I mentioned the pinion depth-setting tools, which are generally called out as being needed if you don't have the original pinion shim stack as reference. What else do you think is necessary or very good to have?

Bryan

 

[Tail lights]

Good luck on doing your rear end. The one tool you must have more than any other is patience. Also make sure your inch pounds torque wrench is a defecting beam or more preferably a dial type,a click type won't work. Also something I've learned if the specs for backlash for example are 8 to 12 thousandths, what they really mean is 10 exactly. and if you don't get that pattern absolutely perfect and centered perfectly, it will make noise. Be prepared to change your shim pack by .001 at a time when you really get close.

 

[cowger]

Good luck on doing your rear end. The one tool you must have more than any other is patience. Also make sure your inch pounds torque wrench is a defecting beam or more preferably a dial type,a click type won't work. Also something I've learned if the specs for backlash for example are 8 to 12 thousandths, what they really mean is 10 exactly. and if you don't get that pattern absolutely perfect and centered perfectly, it will make noise. Be prepared to change your shim pack by .001 at a time when you really get close.

Thanks, Tail lights! All great advice, for sure. Happily I already have a dial type small torque wrench.

I'm still looking for the proper manual if anyone can point me to it. I think our model diff is "44/216 ICA", if that's correct. Should I be looking for a manual from Dana/Spicer, or is there another Dodge manual that goes into the diff (beyond the base service manual that seems to treat it as one replaceable unit)?