Axle Rebuild - Gear Replacement Necessary?

[jc_chandler]

I'm starting to think about the rebuild of the axles. They have clearly been leaking out of every seal for years so I think all new bearings, seals, ball joints, and u-joints (also one-pieces in the rear). I think I'm going to stick with the stock 3.54 ratio since the #s from the calculator look pretty good with the AX15/Dana300/31" tire combo I'm planning to run. My question is, can I re-use the stock gears if they are in good shape? I ask b/c I was told recently by a local shop that "generally it is best to replace the gears also as with new bearings we will very likely end up a few thousands off on the pattern from were it was. Idea being if we reuse the gears our goal is to try and replace bearings without moving the gearsets. Instead of setting to a good pattern."

Is that legit? I'd like to save a the few hundred bucks on new gears if I can and I don't know enough about diff gear setup.

 

[93_Fummins]

Just put new 4.10s in and justify going 33"s

I'm not a professional installer by any means, but it sounds like they just don't have confidence setting gears or want the new gear sale. I know it's not the simplest process, but I see no reason they couldn't match the pattern back up with fresh bearings and used gears. Perhaps they have done it in the past and it happened to whine afterward because the gears were poorly worn or something. I've also heard that OEM gears tend to be of better quality than aftermarket, so I would be hesitant to swap them out for same ratio if they still looked good and had no signs of bad wear or spider-webbing.

 

[ag4ever]

No reason to replace a good ring and pinion if it is in good shape.

Sounds like a shop that does not know how to setup gears and just hopes all new parts will just fall within spec.

I’d also rather have a good set of original gears over an unknown quality replacement.

 

[jc_chandler]

Great to know, thanks guys!

 

[sdsupilot]

With the AX15 overdrive and living in CO I would be tempted to swap to 4.10. Higher elevation and mountain passes will make the I6 work. As other said, you should be fine to reuse the gears given they are in good shape.

 

[jpnmaine]

If you are doing the work yourself and reusing the gear set. Take pre-measurements. Measure your backlash prior to disassembly and I wish I had done this..take a pattern and snap a pic. I thought i would be able to see the wear in and really relied on back lash when wishing I had a visual of the pattern. My2C.

 

[TravelnMan]

Agree with the above here. The gears are likely still good. The hard work was done ages ago all you need to do is keep the set the same pinion depth and set the backlash the same and your pattern should basically be identical. Take pictures + measurements before disassembly.

 

[Kane]

I have rebuilt quite a few axles myself and had a set with 50,000 miles on a rebuild that I used the old gears. Do a pattern check before removal and then do one again after assembly. I would put money on it they it stays very close to the same. If not then just shim accordingly.