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I'm going to knock on wood right now just to make sure I don't have a problem for saying this, but where's the evidence of the rear diffs breaking on the GX470s at an alarming rate? I'm not saying they don't break, but the percentage of failure seems small like under 5%. You are more likely to pop a rear air spring/bag on the trail than break the rear diff. And I'm talking medium and lower trails not hard core rock crawling like Dan does (he even breaks all the upgraded parts he throws at the rear axle due to his off this chart rock crawling).

Anyways, I just want to make a point that I don't actually see a high percentage of rear diff failures on the GX470. Maybe the same 8" rear diff on 4Runners and Prados and FJCs are also breaking at an alarming rate? I don't visit those sites too much, so I don't know but maybe only the hard core rock crawlers have issues with the rear diffs breaking, but not the trail explorers like me.

I remember on the 80-series lots of people freaked out about the HG failures and a whole bunch replaced them as preventive maintenance. Again, knock on wood, but my son's 80 has 260K+ miles and still on the original HG. I believe that the hype was more serious than the actual HG failures. Again, blown out of proportion.

I just hope I don't jinx myself with the rear diff on my GX470 and on the HG with my son's 80, but I just don't buy the hype.

I think I'm more likely to pop a rear air spring/bag than break the rear diff. In fact, I'm trying to get used rear air bags as spares from a friend who is converting the rear to ICON shocks and coils. I'm more afraid of my air bags than the rear diff.
 
@HomersCanyonero I have discussed this before, and I think it has more to do with PM than it outright breaking. An 8" diff that has never been serviced, then lifted and wheeled will break faster. The PM is to ensure you reset the preload. If you don't PM the preload every 60-80k, wheel, and have a built truck...you will break more easily. The 8" loses preload with use (high torque loads offroad) because of the tower design. If you open up the rear, have the preload checked and adjusted on the mentioned interval you will have a LOT less chance to chip/lose the R&P.
 
If you're 'wheeling the GX on trails where you think the rear 3rd might break, my thought process would be to either get a significantly bigger rear axle, or to switch to another vehicle altogether for those types of trails.
 
@Vlad Thanks for the clarification. That makes more sense now.
 
@Vlad I read your posts regarding the PM of these diffs. This is one of the main reasons I was looking for a spare. after reading, it breaking seemed like it is a when not an if.

I am planning a maiden voyage to Uwharrie in 3 weeks and then a weekend in South Pittsburgh TN (adventure offroad park) and I just want to be sure I can get home.
 
I broke 2 8" rear ends (1 in north GA stock, one in Moab 4.56ed). The preload backs off the more you wheel. If you have it serviced it will last longer, but if you get into enough rough stuff, it will increase the likelihood for sure.
 
So I'm definitely going to service our rear diff before summer wheeling season, but wrestling with whether on not to do it myself. I've never worked on one before and naturally don't want to screw it up. I was thinking about bringing the 3rd member over to Valley Hybrids, but if I go through all the trouble of taking it off myself should I just tighten the carrier bearing pre-load? Zuk's tutorial makes it seem pretty straightforward, but I'd love some input from people who tinker with their own diffs.

Worst case scenario I remove it, chicken out, and then just bring it to a shop!
 
Worst case scenario I remove it, chicken out, and then just bring it to a shop!
That is about where I am too. Since it is basically setting torque values and not setting up a new R&P, I am inclined to try it myself.
 
It's pretty easy to tighten the bearing side cap. If you change to solid spacer for the pinion bearing it would be more work and need some specialized tools.

I use 3ft long Strut material and a couple 8 mm bolts as the driver for the bearing side cap.
 
Does anyone have a link to the specs of the side caps (torque) and pinion preload? I would like to do this before I go to Adventure Offroad Park in TN next month.
 
Thank you Vlad, I read through it a few times. He stated that it was 80lbft before it started moving but he didn't state the final torque value of the side caps. Also, should I check the pinion pre-load while I am there?
 
Yes.
 
Now that i have learned that the locker from a 4x2 tacoma,will almost bolt in, i think that is the direction i will go. Some of which already have a 3.73. But for now (this season) I need to make sure my equipment survives as it is
 
I use baker offroad
 

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