Rear Diff Issue (1 Viewer)

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Dec 1, 2022
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Location
Mississippi
Hi all--longtime lurker. But it is now time to post. My '09 GX was totaled last month. Couldn't have possibly picked a worse time to buy a used vehicle. I searched for 3 weeks. Last Tuesday I found a '06 GX four hours away. 227k on the odometer. The records on the Lexus Drivers website looked good (especially compared to all the other GXs I was looking at), and had been cared for later in its life by an independent shop owned by a former Toyota tech.

So, when I test drove it I could hear a slight whining noise from what I believed to be the right rear wheel; it would get slightly louder with speed. I (mistakenly) believed this to be the RR wheel bearing needing to be replaced (was familiar with the issue having dealt with it on my '09). I decided to purchase anyway. Needless to say, mistakes were made...

Took it to a local shop today to get oil changed and investigate the noise this morning. I used this shop once before to do the air bag delete in my '09. They have, I sh-t you not, 7 LCs out front. Apparently every employee there owns a LC. Was always jealous.

Long story short, they informed me that my rear diff needed to be replaced. Parts + labor $2,900 (I bet this doesn't include tax). I am, to put it mildly, crushed. But I am solely to blame. I guess my question is whether this price falls in line for what's expected for this repair. Also would be interested in hearing any advice on confirming the this is, in fact, the problem. Thanks.
 
Did they tell you what specifically is wrong with the rear differential? I would ask for an itemized quote and diagnosis or get a second opinion. These GXs use a drop-out third member differential, which theoretically should not be a big deal to replace with a rebuilt or good used part (though I have not yet replaced one).
 
Welcome! I’m sure you can find a used 3rd member or diff for a lot cheaper . Along with what Rednexus said find out what exactly is the problem.
 
Did they tell you what specifically is wrong with the rear differential? I would ask for an itemized quote and diagnosis or get a second opinion. These GXs use a drop-out third member differential, which theoretically should not be a big deal to replace with a rebuilt or good used part (though I have not yet replaced one).

Thanks for the reply. To be honest, it was such a gut-punch, I did not ask specifics. They did give me an itemized quote:
"Rear diff needs hub bearings, collars, and seals. Labor $1,115.00. Parts and labor installed for new 3rd member diff is $2,939.00"

I got a recommendation for another local shop that I'm going to take it to, hopefully tomorrow. Now that I've had time to come to grips with it, I'll be prepared to ask for a lot more specifics. I suppose I should also consider taking it to Toyota/Lexus to get their opinion.
 
Wait! If you are screwed and you have to rebuild the diff, then spend a little more and get the 8.2” rear axle that’s more robust than the stock 8” rear diff.

A lot of people who have their 8” rear diff explode while wheeling…strongly consider going 8.2”

Just search YouTube for gx470 rear diff issues and you will see several videos of this
 
Wait! If you are screwed and you have to rebuild the diff, then spend a little more and get the 8.2” rear axle that’s more robust than the stock 8” rear diff.

A lot of people who have their 8” rear diff explode while wheeling…strongly consider going 8.2”

Just search YouTube for gx470 rear diff issues and you will see several videos of this
If I am screwed, this is a hell of an idea. Will definitely look into this
 
Additional question: assuming the rear diff does in fact have to be replaced, am I risking likely further damage to other parts of the drivetrain by continuing to drive it?
 
For just a 3rd member the price seems very high. East Coast Gear Supply sells rebuilt 3rd members for less than $1k. You can probably find a used one for less than that. The labor also seems kind of high for a straightforward job, but again I have not personally done one. I would shop around and get a 2nd opinion

You should still be able to drive the GX some, albeit I would stay local with it and get if fixed soon.

Edit: $735 plus shipping for a rebuilt 3rd member:
 
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For just a 3rd member the price seems very high. East Coast Gear Supply sells rebuilt 3rd members for less than $1k. You can probably find a used one for less than that. The labor also seems kind of high for a straightforward job, but again I have not personally done one. I would shop around and get a 2nd opinion

You should still be able to drive the GX some, albeit I would stay local with it and get if fixed soon.

Edit: $735 plus shipping for a rebuilt 3rd member:
Thanks for the response and providing that link. Seems reasonable. I'm taking it to another guy Monday and will see what he says.
 
Additional question: assuming the rear diff does in fact have to be replaced, am I risking likely further damage to other parts of the drivetrain by continuing to drive it?
yes , you will. Catastrophic failure of the rear third member will ensue if it gets worse. I agree with replacing just the third or swapping the housing. Labor is actually cheaper swapping a housing if they don't have to rebuild it.
 
If you’re inclined, swapping an 8.2 can be done in the driveway and they have the coil seats so that’s another minor savings.
 
@Counsel turns out we're in an almost identical situation! I just purchased an '07 GX470 with 190k miles. Prepurchase inspection strongly indicated a shot rear diff and I just got it confirmed by my local mechanic yesterday.

I just posted about it here but then saw your post immediately afterward.

I've been looking at swappable 3rds from East Coast Gear Supply.

Would you mind sharing what you decided to go with? Did you just keep it stock or did you end up upgrading to the 8.2"? If you have time to share I'd love to hear what you learned or what resources you read/watched in making the decision. I'm not familiar with the pros of upgrading to 8.2.

Thanks in advance!!
 
@Counsel turns out we're in an almost identical situation! I just purchased an '07 GX470 with 190k miles. Prepurchase inspection strongly indicated a shot rear diff and I just got it confirmed by my local mechanic yesterday.

I just posted about it here but then saw your post immediately afterward.

I've been looking at swappable 3rds from East Coast Gear Supply.

Would you mind sharing what you decided to go with? Did you just keep it stock or did you end up upgrading to the 8.2"? If you have time to share I'd love to hear what you learned or what resources you read/watched in making the decision. I'm not familiar with the pros of upgrading to 8.2.

Thanks in advance!!
I am. There is only pro with 8.2 upgrade aside from the money. The stock 8" will pop. Usually when you most want it not to. If you are already down just source an 8.2 from a 10+ FJ auto or 4Runner. They bolt right up unless you have KDSS, in which case you have to move mounts (welding). I never, ever recommend building an 8" and thinking it will be stronger. It won't. Better gears? Solid spacer? locker? Yeah....tried all of that. Still blew the 8". That is why I was the first to go to the diamond housing and 9.5" land cruiser diff. I was so frustrated to break a perfect build on an 8" with 4.56 locker, etc. after I broke it in. After I shook it down offroad. After I drove it to Moab....it goes PING and chipped a tooth as I exit a trail. I was done lol.
 
I am. There is only pro with 8.2 upgrade aside from the money. The stock 8" will pop. Usually when you most want it not to. If you are already down just source an 8.2 from a 10+ FJ auto or 4Runner. They bolt right up unless you have KDSS, in which case you have to move mounts (welding). I never, ever recommend building an 8" and thinking it will be stronger. It won't. Better gears? Solid spacer? locker? Yeah....tried all of that. Still blew the 8". That is why I was the first to go to the diamond housing and 9.5" land cruiser diff. I was so frustrated to break a perfect build on an 8" with 4.56 locker, etc. after I broke it in. After I shook it down offroad. After I drove it to Moab....it goes PING and chipped a tooth as I exit a trail. I was done lol.
Really good stuff to know. I'm pretty quickly being convinced to go to the 8.2. I'm pretty intimidated by the idea of having to source one given my complete lack of experience and inability to verify quality, but I'm thinking it will be worth the learning/struggle.

Do you know what a reasonable price would be for an 8.2 assembly in good shape? I really have no basis of comparison and don't want to either pay too much or be too demanding when trying to purchase one.

Thanks again for all the recs. Super helpful.
 
Really good stuff to know. I'm pretty quickly being convinced to go to the 8.2. I'm pretty intimidated by the idea of having to source one given my complete lack of experience and inability to verify quality, but I'm thinking it will be worth the learning/struggle.

Do you know what a reasonable price would be for an 8.2 assembly in good shape? I really have no basis of comparison and don't want to either pay too much or be too demanding when trying to purchase one.

Thanks again for all the recs. Super helpful.
A new 8.2 housing from Toyota is around $1K and a new 3rd member is on the order of $1,700-2,000, depending on if you go e-locked or not. In my neck of the woods, a complete used 8.2 diff is $2-3K non-locked and $3-4K with a factory elocker. I've read you can re-use your existing 8" axleshafts, brakes, etc. If you are concerned with buying used, it's really nominally more expensive to go new from Toyota (assuming the axleshaft/brake interchange is verified). Also the axles on Toyotas can get super-rusty, which can be a concern with a used housing.

Most 8.2s are going to come from a wrecked and totaled 4Runner, so you'll need to make sure the 4Runner was not hit in the rear or sideswiped, which can pretty easily damage the axle housing.
 
A new 8.2 housing from Toyota is around $1K and a new 3rd member is on the order of $1,700-2,000, depending on if you go e-locked or not. In my neck of the woods, a complete used 8.2 diff is $2-3K non-locked and $3-4K with a factory elocker. I've read you can re-use your existing 8" axleshafts, brakes, etc. If you are concerned with buying used, it's really nominally more expensive to go new from Toyota (assuming the axleshaft/brake interchange is verified). Also the axles on Toyotas can get super-rusty, which can be a concern with a used housing.

Most 8.2s are going to come from a wrecked and totaled 4Runner, so you'll need to make sure the 4Runner was not hit in the rear or sideswiped, which can pretty easily damage the axle housing.
Super helpful, that's great to know that the price diff on new 8.2 housing vs. used isn't always much. That might mean it's not worth my hassle trying to source a used one, particularly since I don't have a ton of time to go looking at different ones...and even if I did I might miss something given my lack of experience.

I've been looking at rebuilt thirds from East Coast Gear Supply and it looks like I can source what I need at around $1k if I don't put in a locker.

Given that these vehicles have ATRAC, is it a reasonable choice to opt for no locker in the diff itself? I've been reading enough to gather that there are strong opinions on both side of the argument, but I'm more interested in making sure the "ATRAC only" people aren't completely crazy.
 
Super helpful, that's great to know that the price diff on new 8.2 housing vs. used isn't always much. That might mean it's not worth my hassle trying to source a used one, particularly since I don't have a ton of time to go looking at different ones...and even if I did I might miss something given my lack of experience.

I've been looking at rebuilt thirds from East Coast Gear Supply and it looks like I can source what I need at around $1k if I don't put in a locker.

Given that these vehicles have ATRAC, is it a reasonable choice to opt for no locker in the diff itself? I've been reading enough to gather that there are strong opinions on both side of the argument, but I'm more interested in making sure the "ATRAC only" people aren't completely crazy.
ATRAC is very capable, if you air down and have good tires. I've gotten my GX stuck once and had ATRAC problems, when not airing down and sliding off into a mudhole. When aired down to 15-20 psi it works very well for most light/moderate wheeling and has taken everything I've thrown at it, including some nasty mudholes.

That being said it's still a reactive system (activates after slippage has already occurred). Where it can have problems is in diagonal spin, where you get 1 front wheel and 1 back wheel in a low-traction situation. It can take if a few seconds to "figure things out" while you are in a precarious spot. I've gotten my rig in this kind of spot maybe 2X since having it. It can also be confounding in snow by not allowing wheelspin unless you really punch the throttle.

I'm planning F&R lockers in my rig and an 8.2 upgrade. Yes, it's overkill, but I want to future-proof it. If you aren't going to do heavy off-roading/overland, you'll be just fine with good tires, a compressor to air back up, and ATRAC with no locker.
 
@eternalwarrior whats your intended off-roading goals with this rig? Tire size?

Medium rock crawling => get rear locker.

Big tires 34s or 35s, consider regearing as well.


If your goal is to run 33s max and do some mild rock crawling, then you’ll be good with stock gears and no rear locker.
 

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