GX470 Unsprung weight grenading rear diff

[Smileyshaun]

I think it’s weird to grenade a 8” Toyota diff , are they getting mud and water in the diff ? Unless it’s a completely different 8 inch rear end than the older Toyota stuff have plenty of friends with dual cases, beadlocks 38s locked on both ends who don’t blow rear ends . Most damage I’ve seen is my buddy rolled his runner 4 times up at Fordyce and bent the rear axle but the 3rd member was fine .

 

[jewishoverlander]

I asked Kendra directly and they said 62lbs but at home they weighed at 63.2 lbs . But weight aside I’ve been very happy with the tires with their skinny size only needing an inch of lift clear on my truck with no rubbing, If I would’ve gone the traditional route with more of a 35x12.50 I probably would’ve needed about 5 inches of lift to make it clear

Very strange... Im gonna call them again tomorrow. Weird that theyd tell you that they weigh 62lbs and the 33s weight 61lbs to me on the phone. I seen emails from them to others claiming multiple weights too and also people who said various weights on the phone. Very annoying. Thanks for the info

 

[jewishoverlander]

I think it’s weird to grenade a 8” Toyota diff , are they getting mud and water in the diff ? Unless it’s a completely different 8 inch rear end than the older Toyota stuff have plenty of friends with dual cases, beadlocks 38s locked on both ends who don’t blow rear ends . Most damage I’ve seen is my buddy rolled his runner 4 times up at Fordyce and bent the rear axle but the 3rd member was fine .

Honestly Im not sure... is it the same rear diff as the 4th gen 4R? All I know is its fairly common in GXOR. Not like its every single week but its common enough that the group agreement seems to be it will happen to most people eventually its only a matter of time? But again I dont actually know

 

[tacollie]

Do you mean open diffs as in no lockers? Cause the GX does have a center diff lock. IDK if you participate on GXOR at all (or have a GX470) but lots of people are grenading their 8" - is it every week? No. But the more established members seem to indicate that its more of a when not if type thing. But maybe they just have a confirmation bias. I asked here because the advice seems less subjective and more objective on here

Yes. Front and rear are open. I have some seat time in a GX. My brother had one before they were cool. I'm not on GXOR ever. The 8" is on the small side for the weight and hp but it is adequate. Especially on modest tires like 33x10.5".

Steady throttle control is key. Don't mash the gas pedal. Be patient and stay calm. Every single time my friends and I have broken something on the trail it was either us loosing our cool or trying to look cool. Or lack of maintenance. Also rust?. Being level headed will have a bigger effect on your differentials than your tire size imo.

Have you listened to the Overland Journal podcast? There was a great quote by Greame Bell. In so many words he said reliability is something you worry about sitting at home. Things happen no matter how much you prepare. That's part of the fun.

 

[BigSwede]

Shock loading is more likely to damage your diff than simple tire weight. Larger diameter tires increase leverage on the diff and do increase shock loading. But 33s are a fairly small increase over stock.

 

[Smileyshaun]

Very strange... Im gonna call them again tomorrow. Weird that theyd tell you that they weigh 62lbs and the 33s weight 61lbs to me on the phone. I seen emails from them to others claiming multiple weights too and also people who said various weights on the phone. Very annoying. Thanks for the info

I could have been off with my weighing to , the sidewalls are good and thick and the side lugs are thicker than the pictures look .

If your concerned about tire weight look into the DC trail country exp , had them on my xterra and they worked very well and for aggressive as they are where rather quiet with good road manners plus they where skinner than other manufacturers of the same size so I could stuff a 35 on with only 2” of lift and some trimming .

 

[bkg]

IMHO - you're overthinking it.

I've put literally hundreds of thousands of miles on Toyota 8" diffs with everything from 31 to 37" tires.

Drive like an idiot, sure... maybe. Ignore routine maintenance, sure... maybe. Get water in the diff, sure... But as long as it's setup correctly, you should be just fine.

And IIRC, you should have the "8.4" diff....

 

[jewishoverlander]

Shock loading is more likely to damage your diff than simple tire weight. Larger diameter tires increase leverage on the diff and do increase shock loading. But 33s are a fairly small increase over stock.

Looks like the consensus is that Im overthinking it. But these 33s would yield a 35% increase over stock sprung weight. Obv I know of GXs with wheels that add 10+lbs and then 35s which are closer to 70lbs so theyve got a solid 60% increase and they aren't auto destroying their diffs.

 

[Smileyshaun]

For reference this is the rig I was mentioning that beats the holy hell out of that Toyota 8” diff
it weighs a ton and the tires I would not be surprised if they where 150lbs , there must have been 20lbs of welding wire in the wheels by the time we where done making them . Like I said unless they completely changed the diffs on the gx I would be surprised they blow quite often ..... maybe it has constant extra stress being awd ????

the place you’ll notice unsprug weight the most will be on the road a heavytire will lead to a bigger hit on mpg and acceleration.

 

[F350joe]

Few things....

1. don’t spin and hop the rear and you should be fine.

2. Learn to use the left foot lightly on the brake in wheel hop situations.

3. Under loaded is better than overloaded. If you want to be a wheeler and an overlander you will do neither very well without spending a ton of money.

4. Service the rear-end and re-tighten the pre-load.

I’m running Wildpeaks 255/80 load E and saw no difference in mpg. I also kept all my front bumper, trimming that will hurt MPG more than anything. Air down, skinnies will get a very firm contact patch. Air up you will get little roll resistance. I was a wider is better guy too but love the skinnies, even at 95mph. I do have 1.25” wheel spacers to widen the stance and to solve clearance issues but still inside the wheel wells which helps with MPG too.
Tried to upload some detailed photos for you but this site is outdated and wont allow it. Facebook GXOR is a much more informative platform, i suggest asking your question on there of even Ih8mud. They don’t restrict the size of photos to potato camera resolution and proabaly 1000x the audience.

 

[slomatt]

I've always wondered why the GX470 forums report "a ton" of broken rear differentials, but you don't hear the same thing from 4th gen 4Runners or FJCs which run the same 120 platform. Obviously the GX470 is heavier and the V8 has more torque, but people put add a lot of weight to their 4Runners and don't seem to have the same diff issues. Perhaps it's the additional low end torque from the V8?

Regardless, I agree with the recommendations to avoid shock loading the drive train. Specifically, avoid spinning your wheels in low traction situations. When a wheel spins you have 90+ lbs of rotational weight, and if that suddenly finds traction it puts a huge load on the ring and pinion and the rest of the drive train. I learned this the hard way in a Jeep where I blew the front driveshaft's CV join in half.

 

[phsycle]

It’s not prevalent. It’s a few folks who butt whip their rig to death, break stuff, then complain on the net, which gets regurgitated over and over again, until it becomes a national crisis.
A lot of issues are experienced by a very few. This is true for Toyota folks, as well as most all other automakers.

 

[bkg]

I've always wondered why the GX470 forums report "a ton" of broken rear differentials, but you don't hear the same thing from 4th gen 4Runners or FJCs which run the same 120 platform. Obviously the GX470 is heavier and the V8 has more torque, but people put add a lot of weight to their 4Runners and don't seem to have the same diff issues. Perhaps it's the additional low end torque from the V8?

Regardless, I agree with the recommendations to avoid shock loading the drive train. Specifically, avoid spinning your wheels in low traction situations. When a wheel spins you have 90+ lbs of rotational weight, and if that suddenly finds traction it puts a huge load on the ring and pinion and the rest of the drive train. I learned this the hard way in a Jeep where I blew the front driveshaft's CV join in half.

1st Gen Tundra and Sequoia use the same components as well... and are (IIRC) heavier.

 

[jewishoverlander]

It’s not prevalent. It’s a few folks who butt whip their rig to death, break stuff, then complain on the net, which gets regurgitated over and over again, until it becomes a national crisis.
A lot of issues are experienced by a very few. This is true for Toyota folks, as well as most all other automakers.

Is it for sure tho? The guy who started GXOR and was the one of the first people modding GXs for off road in the USA and was ordering parts for Prados when there wasnt a market for anything yet has been in the group and observed the most GX convos than any living person and his famous line is "Its not a matter of if the rear diff will grenade, its a matter of when". He genuinely believes that anybody who takes thier rig off road will eventually blow their 8" diff in a GX470...

 

[phsycle]

Is it for sure tho? The guy who started GXOR and was the one of the first people modding GXs for off road in the USA and was ordering parts for Prados when there wasnt a market for anything yet has been in the group and observed the most GX convos than any living person and his famous line is "Its not a matter of if the rear diff will grenade, its a matter of when". He genuinely believes that anybody who takes thier rig off road will eventually blow their 8" diff in a GX470...

Sure, just like folks told me it was only a matter of time when my 2-pinion front diff of my 100-series will explode at any given time. Driving a Ford will leave me stranded. None of this has happened.
It usually the same folk who wonder how I roam the desert without a RTT, rotopax, and a custom drawer system.

Now, can it? Of course. Then again, lots of things can happen. If you’re afraid of the “what if’s”, just stay home.