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After using 4.88 for about a year now, I don't see any drawback to this ratio. The mild increase in high speed (80 mph+) RPM over say a 4.56 or 4.33 (maybe 100 rpm?) isn't enough into the RPM range to increase engine noise at all (and at those speeds there are other noises that are louder). But the torque available low in the RPM range is much improved. I see the concern about the Nitro gears, and did have some wear in shavings at the 500 mile break in change. There was also some 'gear noise' for a few thousand miles. I'm up around 8000 to 10000 miles on the gears (I'll go double check that) and now they are silent as the factory drivetrain was (or at least my recall of that drivetrain). I certainly don't notice anything out of the ordinary in use.
I know OP has locked in on 4.33 for many good reasons, just putting this here for the ratio discussion.
@TeCKis300 Nitro was selling an alternative eLocker when I geared up. It locks up good. Can't find it on their site, but if you want a second option you could reach out to them. It's an Auburn part, in the eCTDMax line, and runs open/locked.
From my assessment, 4.88s are a pretty large jump in gearing to 4.3s, ~300rpm in the tallest gears at highway speeds, almost a full transmission gear difference. At least for me with stock aero, almost stock weight when not towing, and other considerations, 4.3s were the ticket putting things right back to stock overall gearing. I could definitely see 4.88s as the right choice for heavier built rigs.
More data crunched here:
Definitive 200-series Gearing Reference
So I had a little time this morning to put together a chart combining transmission gearing of 6-speed vs 8-speed, diff ratios, and tire sizing into an overall gearing reference. Hoping this will be useful for those trying to understand how their changes are going to effect overall gearing of...
forum.ih8mud.com
I did look into the Auburn locker. Not much feedback to be found. From the minimal commentary from jeepers, seems to have a marginal track record.
Toyota 9.5'' 32 Spline, Auburn Electric Locker
Toyota 9.5' 32 Spline, Auburn Electric Locker
www.justdifferentials.com
How available is a e-locked rear on the salvage market? I would assume tough to get as they were pretty limited in the US market. Harrop is a better design although significantly more expensive plus additional setup.
More than I initially thought and seems reasonably easy to source. car-part.com
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I think that’s the beauty of the 4.30 ratio diffs. Other than swapping the part time actuator on the front I think they’ll drop right in. That’s what I would do personally, and I’ve considered doing that. If you’re going to the trouble of rebuilding the diffs, I’d jump right to 4:56 with new gears/bearings, etc.
Where did you source your parts? Ebay? Local wrecking yard?
Yes and yes. My go to for recycled grade A parts is car-part.com. Lots of stuff on Ebay too. Craigslist less so for a niche vehicle but probable as well. I have used car-part.com for decades, successfully every time. As with anything, especially in the used market, your experience may vary.