Stronger Rear axle swap ideas into gx/4th 4r/ 2nd taco

[HutchOven]

Looking for tech on a rear axle option for my gx470. This would relate to all models from this Era because what I want is a junkyard Axle (like a Dana 60) with after market capabilities to still run the speed sensor and whatever abs sensors our rear axles currently have.

I know you can spend a lot on a brand new one ready to go, but it seems a bit of a waste when the Dana 60 rear litter the junkyards and there are a few options out there for 6x5.5 hubs for them that you can swap all the brakes over to.

Link brackets etc. are easy to cut off and weld back on but the sensors are the issue. So what has anyone else done or seen done?

 

[who done it]

Haven't seen this yet. Only thing I've seen so far is the Currie Rock Jock axle for the FJ.

I'd love to see if we could just use a junk yard axle with a bit of welding.

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[Jetboy]

There's a few options.

For the GX470 - I'd find an 8.2. They are not a ton larger, but much stronger. Internally - they're a lot more robust. The pinion shaft is much larger and the pinion main bearing is also a lot bigger. The result is a lot less deflection under load and basically no examples of broken parts I know of with factory gear setups. The 8.2 pinion is larger than a Dana 60. (ring gear is obviously smaller).

Here's the two side by side:

Beyond this - Diamond axle builds a Land Cruiser 9.5 center with 4Runner/GX outers. It's a bolt in swap as well.

Or you could make a custom Land Cruiser 9.5 rear end out of a junkyard 9.5. You can buy them with e-lockers, but I'm not sure how they interact electronically with a GX wiring. The main difference is that you'd need to have the rear axles re-drilled for 6 bolt pattern. Since the 6 hole pattern is narrower, I *think*, but haven't done it, that you could simply re-drill without the need to weld in any of the old 5 lug holes. I don't know enough about the linkage mounts - but it's possible that it may even bolt in place or be very close to bolt in with some adjustable links that are not too expensive. The 5 link design is the same. I just don't know about the spacing. I also don't know about ABS tone ring count - if it's the same on both, it'd be very easy to mate the axle to the GX system. Junkyard LC100 rear axles go for around $500-800 that I've seen.

Next option is the Tacoma 8.7. It's actually 8.9" ring gear. It's probably stronger than any of the older OEM Dana 60 axles because of the larger stronger pinion and pinion support bearing. They're pretty cheap. But they have drum brakes...

If you wanted to get something shipped - the fortuner has the 8.9" ring gear rear axle just like the Tacoma, but is already setup for 5 link and comes with disk brakes. It's probably a bolt in swap. And it also has an internal e-locker option. The downside is that finding one in the USA will not be common and shipping probably isn't cheap.

Tundra rear axles are BEEF, but they're heavy and probably overkill for a GX. They are pretty reasonable cost wise and pretty widely available. Like the junkyard 9.5LC, you'd have to re-drill the rear for the 6 hole pattern. And they're pretty wide for a GX. I'm sure you could get a custom housing or narrow one, but you'd be spending a lot to do it.

After that - you're probably going into more complicated non-toyota options or aftermarket axles. There's maybe a handfull of bolt in options or junkyard axles plus weld on bracket kits.

Biggest thing I'd avoid is a Dana 44. They're almost all or all going to be weaker than an 8.2 that is a very easy and economical swap. So - Dana 60 or bigger if you want any strength benefit.

If you want to fab your own - Ford 9" build kits are pretty cost effective. Biggest downside is that 9" rear axles kinda suck as far as pinion location. It's very low in the housing so your drive shaft will be a rock magnet.

 

[HutchOven]

There's a few options.

For the GX470 - I'd find an 8.2. They are not a ton larger, but much stronger. Internally - they're a lot more robust. The pinion shaft is much larger and the pinion main bearing is also a lot bigger. The result is a lot less deflection under load and basically no examples of broken parts I know of with factory gear setups. The 8.2 pinion is larger than a Dana 60. (ring gear is obviously smaller).

Here's the two side by side:

Beyond this - Diamond axle builds a Land Cruiser 9.5 center with 4Runner/GX outers. It's a bolt in swap as well.

Or you could make a custom Land Cruiser 9.5 rear end out of a junkyard 9.5. You can buy them with e-lockers, but I'm not sure how they interact electronically with a GX wiring. The main difference is that you'd need to have the rear axles re-drilled for 6 bolt pattern. Since the 6 hole pattern is narrower, I *think*, but haven't done it, that you could simply re-drill without the need to weld in any of the old 5 lug holes. I don't know enough about the linkage mounts - but it's possible that it may even bolt in place or be very close to bolt in with some adjustable links that are not too expensive. The 5 link design is the same. I just don't know about the spacing. I also don't know about ABS tone ring count - if it's the same on both, it'd be very easy to mate the axle to the GX system. Junkyard LC100 rear axles go for around $500-800 that I've seen.

Next option is the Tacoma 8.7. It's actually 8.9" ring gear. It's probably stronger than any of the older OEM Dana 60 axles because of the larger stronger pinion and pinion support bearing. They're pretty cheap. But they have drum brakes...

If you wanted to get something shipped - the fortuner has the 8.9" ring gear rear axle just like the Tacoma, but is already setup for 5 link and comes with disk brakes. It's probably a bolt in swap. And it also has an internal e-locker option. The downside is that finding one in the USA will not be common and shipping probably isn't cheap.

Tundra rear axles are BEEF, but they're heavy and probably overkill for a GX. They are pretty reasonable cost wise and pretty widely available. Like the junkyard 9.5LC, you'd have to re-drill the rear for the 6 hole pattern. And they're pretty wide for a GX. I'm sure you could get a custom housing or narrow one, but you'd be spending a lot to do it.

After that - you're probably going into more complicated non-toyota options or aftermarket axles. There's maybe a handfull of bolt in options or junkyard axles plus weld on bracket kits.

Biggest thing I'd avoid is a Dana 44. They're almost all or all going to be weaker than an 8.2 that is a very easy and economical swap. So - Dana 60 or bigger if you want any strength benefit.

If you want to fab your own - Ford 9" build kits are pretty cost effective. Biggest downside is that 9" rear axles kinda suck as far as pinion location. It's very low in the housing so your drive shaft will be a rock magnet.

Thanks for info.
Is there any reason you didn't mention the 8.4" older tundra Axle? Most of the damage I see with the 8" is the ring gear itself, not the Pinion or bearings. Although flex could aid to that ring gear breaking teeth.

I would like to stay with a 8/8.2/8.4 for ground clearance but not sure it's cost effective in the end. Was thinking of cryo for the entire r&p/bearings and running an arb for strength and than some 4340 shafts.

As far as width, I need it wider in the rear. Likely going with rclt or btf for the front. If fox wasn't a 40 week backorder, I would've already ordered. Figure I have plenty of time to plan now.

 

[Jetboy]

Thanks for info.
Is there any reason you didn't mention the 8.4" older tundra Axle? Most of the damage I see with the 8" is the ring gear itself, not the Pinion or bearings. Although flex could aid to that ring gear breaking teeth.

I would like to stay with a 8/8.2/8.4 for ground clearance but not sure it's cost effective in the end. Was thinking of cryo for the entire r&p/bearings and running an arb for strength and than some 4340 shafts.

As far as width, I need it wider in the rear. Likely going with rclt or btf for the front. If fox wasn't a 40 week backorder, I would've already ordered. Figure I have plenty of time to plan now.

Edit:
My knowledge of the 8.4 was totally wrong.

The 8.4 is pretty similar to the 8.2. I'm not sure why it's called an 8.4. It's a bit smaller differential than the 8.2, but a bit bigger than the 8" and stronger where it matters most - pinion shaft size. Go figure. I looked up the pinion size. The pinion shaft on the 8.4 is bigger than that on the 8". So it probably is a meaningful upgrade as well. I'm just not very familiar with them. I'm not sure the carrier cap bridges made a lot of difference. But the pinion size probably did. After reading a bit more - I think the 8.4 might also be a good upgrade. Probably pretty close to the 8.2. Pinion shaft diameter is the same as the 8.2. Assuming the housing is also relatively similar, they are probably about a wash in terms of strength. And IIRC they share the same mounting flange pattern. So maybe for your GX - it might be a better alternative to an 8.2 housing swap? I don't know if the spider gear/axle shaft splines are interchangeable. But I'd venture a guess that they are.

The most common reason for failure is the pinion head deflecting under load. Usually the damage will occur on the ring gear teeth, but the cause of the failure is deflection of the pinion away from the ring gear and then the mesh being less depth - the weaker/smaller teeth on the ring gear break off before the pinion teeth. The pinion teeth have a different thrust angle and effectively are stronger.

The way to make it stronger with the same size ring gear is to make the pinion more rigid. That's where all the major upgrades are for the 8.2 appear to be to me looking at them side by side. Shorter fatter pinion, bigger pinion bearing, more reinforcement in the housing at the pinion support, etc.

The carrier is almost identical - but the 8.2 uses 12 ring gear bolts vs 10 on the 8", not sure there's any material strength advantage there. I've never seen or heard of an failure of ring gear bolts or ring gear failure that could be linked to not having enough. Maybe it has some value? Not sure.

(FWIW - ignore ring gear thickness - that's just a function of the gear ratio differences, thicker ring gears are needed to move the gear teeth out from the mounting surface to reach the smaller pinion head gear - fewer teeth - and the pinion is the weak link usually. That's why lower gear ratio sets are typically weaker than higher gear ratio set all else equal)

Also - probably more important than any of my comparison and analysis is the empirical evidence. Just looking at what works and what breaks - the 8.2s just aren't breaking much. The only failures I know of are aftermarket gears on very heavy trucks. I don't know whether to chalk that up to the gear quality, the diff strength, or the setup. All of which can be the cause. And even then it's very seldom. So my guess is that it's not inherent in the diff design - my guess is that it's the diff setup that's ultimately the weak link (pinion too shallow or too much backlash (ring gear setup too far from pinion centerline). But I don't know. An 8.2" differential is pretty small for a 7k lb vehicle. It probably gets worse if you're going to a 4:1 or double transfer case setup or other lower crawl ratio.

 

[HutchOven]

Next option is the Tacoma 8.7... But they have drum brakes...

What's so terrible about drum brakes? I've converted to disc before and had lock up issues because the proportioning valve sent too much power to the rear but never the other way around. I guess the rear brakes could be a little weak?

 

[twitchee2]

My buddy put a newer gen tundra axle under a taco, although hes slightly modified..

Taco Sauce TX Pro Build: Custom LT, 37’s and Tundra Axle Swap

Taco Sauce TX Pro Build: Custom LT, 37’s and Tundra Axle Swap | Page 36 | Tacoma World

 

[yotantexas]

My brother just put a 8.2 under his GX470 with 4.88 gears and air lockers front and rear. He just did a 3000 mile road trip and we met up in Moab to run a hand full of trails. Everything performed great. This was done pulling a small tear drop trailer. Only on 33s now but plans to step up to 35s.

 

[gm350reratliff]

There's a few options.

For the GX470 - I'd find an 8.2. They are not a ton larger, but much stronger. Internally - they're a lot more robust. The pinion shaft is much larger and the pinion main bearing is also a lot bigger. The result is a lot less deflection under load and basically no examples of broken parts I know of with factory gear setups. The 8.2 pinion is larger than a Dana 60. (ring gear is obviously smaller).

Here's the two side by side:

Beyond this - Diamond axle builds a Land Cruiser 9.5 center with 4Runner/GX outers. It's a bolt in swap as well.

Or you could make a custom Land Cruiser 9.5 rear end out of a junkyard 9.5. You can buy them with e-lockers, but I'm not sure how they interact electronically with a GX wiring. The main difference is that you'd need to have the rear axles re-drilled for 6 bolt pattern. Since the 6 hole pattern is narrower, I *think*, but haven't done it, that you could simply re-drill without the need to weld in any of the old 5 lug holes. I don't know enough about the linkage mounts - but it's possible that it may even bolt in place or be very close to bolt in with some adjustable links that are not too expensive. The 5 link design is the same. I just don't know about the spacing. I also don't know about ABS tone ring count - if it's the same on both, it'd be very easy to mate the axle to the GX system. Junkyard LC100 rear axles go for around $500-800 that I've seen.

Next option is the Tacoma 8.7. It's actually 8.9" ring gear. It's probably stronger than any of the older OEM Dana 60 axles because of the larger stronger pinion and pinion support bearing. They're pretty cheap. But they have drum brakes...

If you wanted to get something shipped - the fortuner has the 8.9" ring gear rear axle just like the Tacoma, but is already setup for 5 link and comes with disk brakes. It's probably a bolt in swap. And it also has an internal e-locker option. The downside is that finding one in the USA will not be common and shipping probably isn't cheap.

Tundra rear axles are BEEF, but they're heavy and probably overkill for a GX. They are pretty reasonable cost wise and pretty widely available. Like the junkyard 9.5LC, you'd have to re-drill the rear for the 6 hole pattern. And they're pretty wide for a GX. I'm sure you could get a custom housing or narrow one, but you'd be spending a lot to do it.

After that - you're probably going into more complicated non-toyota options or aftermarket axles. There's maybe a handfull of bolt in options or junkyard axles plus weld on bracket kits.

Biggest thing I'd avoid is a Dana 44. They're almost all or all going to be weaker than an 8.2 that is a very easy and economical swap. So - Dana 60 or bigger if you want any strength benefit.

If you want to fab your own - Ford 9" build kits are pretty cost effective. Biggest downside is that 9" rear axles kinda suck as far as pinion location. It's very low in the housing so your drive shaft will be a rock magnet.

Very good info here! One thing I’d add is with the Ford 9”, you could do a reverse rotation third member which would position the pinion up high although, I hear this does compromise strength and oiling a little bit.

I think when the 8” bites the dust in my 4th gen, I’ll just swap in a 8.2 and hope for the best. I think it’ll be the cheapest option, which at this time is priority.

 

[HutchOven]

I decided against the 8.2, it's a time bomb on 37's. The 8.75 is drum which will probably mess up ABS and converting to disc with the initial junkyard Axle cost is almost the same as going new.

As of right now the options I'm looking at is either a custom 9" from Dutchman (no abs) or a lc 9.5 through diamond (with abs but cost is 50% more) but he is waiting on an Axle supplier before he can make them wider and I need at least 4" wider over stock.

Edit: ended up ordering a ecgs Dana 60 since diamond wasn't getting back to me. Started a build thread over in the gx sub