Replacing rear diff in an 07 GX470 (1 Viewer)

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Joined
Jun 6, 2023
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Location
Leicester, NC
Hello all! I'm the excited (first time) owner of a new old 2007 GX470. I've never owned a 4x4 before and would describe myself as "mechanically interested" but a complete n00b. I enjoy reading up and learning, but I can't do much work myself and certainly don't know all the considerations that go into making parts/configuration choices.

I purchased this 470 knowing the rear differential was almost certainly shot. I was able to confirm it with a local mechanic yesterday.

I've seen these folks recommended as a great source for rebuilt 3rds (right term?) on Toyota trucks and am planning to order a replacement from them.

My question: do I add one of their rear locker options?

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I've been reading up on ATRAC (this thread was super helpful), so it seems like adding a rear locker is certainly optional and dealer's choice on these vehicles.

I don't plan on doing crazy climbing, but I may one day work my way up to driving some fairly rutted out trails in Western NC. My current assessment boils down to: ATRAC is incredible, even the older version, and as an amateur I'll probably be very sufficiently served by ATRAC only.

But the part of me that's already paying for a new read diff wonders if I should take the opportunity to add a locker. I am somewhat price conscious so I don't necessarily want to jump straight to "may as well add it while I'm at it", but I don't want to wake up in 5 years and wish I'd included the locker.

Any advice, including general thoughts on replacing the rear diff, would be much appreciated!

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A lot of people will say it's a waste to lock the factory 8" rear because of the weaker ring gear. If you have the disposable funds you might be better served changing out to a newer 8.2 axle and then ordering a locked 3rd from ECGS. This was what I did.
 
A lot of people will say it's a waste to lock the factory 8" rear because of the weaker ring gear. If you have the disposable funds you might be better served changing out to a newer 8.2 axle and then ordering a locked 3rd from ECGS. This was what I did.
Thanks, that's great to know. I just noticed a mention of the 8.2" upgrade in this thread.

I'll dive into researching that. Any recommendations on places to look at for sourcing the parts?
 
Junkyard. You can pull the axle from a newer 4R/460/FJ. Even if it doesn't have the diff you can eat the core charge from ECGS cheaper than it would be to buy a full assembly. Then just swap in the axles from your existing 8.
 
Junkyard. You can pull the axle from a newer 4R/460/FJ. Even if it doesn't have the diff you can eat the core charge from ECGS cheaper than it would be to buy a full assembly. Then just swap in the axles from your existing 8.
Gotcha - I'll look into that. That'd be a whole new adventure for me, that's for sure.

Would the rear axle from any newer year 4R/460/FJ fit in the 07 470?
 
What makes you think the 3rd is bad, specifically?
 
What makes you think the 3rd is bad, specifically?
@bkg very loud whine that increases at higher speeds. I can also hear a low level grind (best way I can think to describe it) even at lower speeds.

The mechanic put it on the lift with one guy giving it some gas and the other listening at multiple points along the rear axle using a stethoscope. He said there was noise all throughout. I don't think they would have had cause to over diagnose. They were originally hoping to find it was just a bearing, but they were pretty sure it was the rear diff after driving it and listening.
 
@bkg very loud whine that increases at higher speeds. I can also hear a low level grind (best way I can think to describe it) even at lower speeds.

The mechanic put it on the lift with one guy giving it some gas and the other listening at multiple points along the rear axle using a stethoscope. He said there was noise all throughout. I don't think they would have had cause to over diagnose. They were originally hoping to find it was just a bearing, but they were pretty sure it was the rear diff after driving it and listening.

Drain the oil and inspect?

Just curious.
 
Drain the oil and inspect?

Just curious.

Interesting, that's a great point. I didn't think of that option. Thanks for the suggestion.

Downside is having to either do that in the place where it will sit until I have the replacement part or having to fill it back up again 😬 (I don't plan on attempting this as my first project more involved than swapping a battery). But it may be worth the hassle just to be 100% sure I need to make such a big expenditure. I'd certainly be happy finding out I can get by with spending less right now...
 
Interesting, that's a great point. I didn't think of that option. Thanks for the suggestion.

Downside is having to either do that in the place where it will sit until I have the replacement part or having to fill it back up again 😬 (I don't plan on attempting this as my first project more involved than swapping a battery). But it may be worth the hassle just to be 100% sure I need to make such a big expenditure. I'd certainly be happy finding out I can get by with spending less right now...

Assuming no rust issues, replacing the 3rd is <60 minute job. It should receive a brake fluid flush at the same time since the axle lines will be disconnected.

I personally wouldn’t get caught up on the “x is stronger” unless you have major plans for power, tires and other shenanigans.

Also a possibility it’s just a u-joint. Hence the reason for checking the oil.
 
Gotcha - I'll look into that. That'd be a whole new adventure for me, that's for sure.

Would the rear axle from any newer year 4R/460/FJ fit in the 07 470?

I don't think the 460 has the right gear ratio and some FJ may not be the right gear ratio.

There are factory locked 8.2 out there that bolt in but are high demand/price.
 
I don't think the 460 has the right gear ratio and some FJ may not be the right gear ratio.

There are factory locked 8.2 out there that bolt in but are high demand/price.
Right but he's talking about buying a 3rd from ECGS so the core doesn't matter. He'll just order a locked 3.73 and send the 3.91 back.
 
Assuming no rust issues, replacing the 3rd is <60 minute job. It should receive a brake fluid flush at the same time since the axle lines will be disconnected.

I personally wouldn’t get caught up on the “x is stronger” unless you have major plans for power, tires and other shenanigans.

Also a possibility it’s just a u-joint. Hence the reason for checking the oil.
Super helpful, thanks. Fair point...I honestly don't have a ton of plans for shenanigans other than maybe some all terrains. The most intense driving I plan to do with this guy is some rutted out overland trails in Western NC, I doubt I'll be taking it to any of the crazy cool courses/climbs out west (or here). My wife and I are hoping to buy a newer year Tacoma at some point and that will probably be our real "investment vehicle".

You're convincing me re: checking the u-joint. I'd hate to pull a perfectly serviceable diff only to replace it with the exact same thing.

Noted re: the break fluid flush. Good to know.

Again, thanks for all the help. I'm really learning a lot here.
 

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