DIY 4.3 Re-Gear

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Still in the early stages and I could use some recommendations on differential install kits/parts.

I've got the keystone pieces in the garage as I attempt to collect the ancillary parts before I rip into the car. Planning a 4.3 re-gear with rear only Harrop e-locker. Locker is less of a priority for me as I want to re-gear for heavy towing with 35s. But while I'm in there sort of thing...might as well get a locker in.

My preference is always OEM parts where possible, versus aftermarket. Sourced the following for their 4.3 ring and pinion gears:

1) '02 LX470 rear differential
2) '12 Tundra (with tow package axle code BO2A) front differential

Questions:
Any lessons learned on parts to refresh replace? I'll likely just source the master re-build kits from Nitro. Can I get away with less, and do I absolutely need everything in the kits? I do want to replace all the carrier bearings and seals. I think I might have enough shims between the 4 diffs on hand, and a few other pieces?

LC200 rear axle bearings have been known to need replacement in higher mileage. As I tow near GCWR, probably a good time while I'm in there right. Anyone have a parts list here? Seals?

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EDIT - Adding completion info hidden deeper in this thread

Link
Front Diff
- 4.3 carrier from Tundra or Sequoia. Probably 08-20?*. 4.3s only came on these models with the optional tow package. Look for door sticker axle code B02A. Parts resellers should have the associated VIN which you can check on Toyota website to confirm tow package in options list.
*I don't know that there were absolutely no changes through 2020 that affect fitment on the 200-series. Mine is from a Tundra 2012 that fit fine.
- Fitting a locker to a front clamshell carrier is supposedly no joke with need for special measuring tools for lash. Fortunately if not looking for a locked front axle, it otherwise drops in after changing out the peripheral ADD actuator
- I sourced mine for $175 shipped

Rear Diff
- 4.3 carrier from 98-02 LC or LX. This ratio came from the 4-speed cruisers of the day (03+ got 5-speeds)
- There are factory locked ones available. Comments suggest this could be retrofitted for air actuation. For LX models only that won't have sway bar interference against the actuator.
- Carrier is directly drop into the 200-series
- Note that the 100-series uses a smaller diameter input flange and snout on the pinion shaft. If you're just looking to source the ring and pinion with full size snout, and will rebuild from your current diff, @bloc was able to sleuth a new OEM R&P 4.3 parts kit ( 41201-80493 )
- I sourced mine for $120; $200 shipped


Costs and Part Numbers
Front diff (~$250, w/o shipping & tax)
1) Used Tundra Carrier Assembly, $175
2) Toyota Red FIPG 00295-01281, $18.91
3) x2 Inner Joint Assembly Snap Ring 90521-37010, $1.27
4) R Intermediate Shaft Output Seal 90311-47013, $14.11
5) L Diff Carrier Output Shaft Seal 90311-47027, $12.97
6) 2 qts Gear Oil
7) Optional Harrop ELocker

Rear Diff (~$1650, w/o shipping & tax)
1) Used 100-series Carrier Assembly, $120
2) Axle Housing Gasket 42181-60060, $7.83
3) x2 Diff Case Side Bearings 90366-50177, $38.00
4) Rear Pinion Bearing 90366-40111, $58.41
5) Front Pinion Bearing (100-series part) 90366-30071, $38.00
6) Pinion Crush Spacer (100-series part) 41231-60030, $16.27
7) Pinion Seal (100-series part) 90311-38066, $10.33
8) x2 Axle Seal 90310-63001, $9.07
9) x2 Axle O-Ring 90301-88077, $4.13
10) 5 qts Gear Oil
11) Harrop Rear Locker (I recommend the fine folks at Cruiser Brothers, Georg @orangefj45 )

Rear Axle Hub Bearing (~$900, optional while you're in there)
1) Right Hub & Bearing 42450-60070, $326.45
2) Left Hub & Bearing 42460-60030, $326.45
3) x2 Axle Seal 90310-63001, $9.07
4) x2 Axle Bearing Retainer 42423-34040, $23.07
5) x2 Axle Bearing Retainer Snap Ring 90520-46014, $2.47
6) Contracted out labor to press and remove $$$
 
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sdnative

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Is the 100 series rear third a direct bolt in to the 200? What are the differences between the Tundra and 200 front third? Or are you just sourcing parts in advance to minimize downtime? Forgive my ignorance.

You could always take the thirds over to Zuk in Phoenix to do the re-gear and locker install. He does great work and can get Nitro R&P.

As far as bearings/seals, I would say if you have everything apart now is the time. I believe the rear bearings on the semi-float axles require a press.
 
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Pre 03 100 series with the 4 speed auto had 4.30 gears.

I would consider solid pinion spacers if you are going through the effort of rebuilding. You will probably need to re setup the rear since you’re replacing the carrier. I would worry less about the front since it’s a part time diff in the Tundra.
 

grinchy

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I had a rear bearing fail after I had already scheduled my diff regear/ rear locker work, so yes, do that. However I did have a fair bit of noise coming off the rear bearings before hand, they didn't go silently. I think the BOM was just the bearings and gaskets/seals. Aside from the press my understanding was it is straightforward.

I did the emergency brakes while in there as well, have to take them off to get to the rear bearing, so no difference in labor.

I see you've got the rear diff already - any reason you didn't source the 100 gen 1 factory rear elocker? it's a pretty straightforward conversion to an air piston actuated locker . . .
 
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I'm not sure, but I don't think any of these donor carriers are a direct bolt on. I intend to take them apart to harvest the ring and pinons. The Tundra rear 3rd member is actually massive and larger than the 200-series at 10.5", vs 9.5" respectively. 10.5" diffs are usually found only in HD trucks, not half tons. Credit to Toyota to putting money where its largely hidden, but counts. Difference likely due to the Tundra being primarily 2WD, and we're full time 4WD. Also a larger pumkin in the 200-series would reduce under axle clearance for its off-road mission. The Tundra/Sequoia front gears are compatible though.

I could source out the builds, but I like the challenge, and trust my own work. I've re-geared a couple times before for other vehicles so this isn't completely unfamiliar territory. I've considered the solid pinion spacer, but will likely just go with the crush spacer to avoid the hassle of multiple teardown/build passes. I sold my old press so will need to get a new one. Harbor Freight occasional use tools with coupon to the rescue. I may have to outsource pressing the axle bearings however.

Good call on the e-brake. Will inspect and check it out.

I considered sourcing the 100-gen factory locker. Wasn't sure the carrier and mechanisms were completely compatible as I hadn't seen any prior findings on this.
 
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TexAZ

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The 99-2000 factory locker is not compatible with the landcruiser sway bar.
The electrical actuator would interfere.
It may work with the lexus without KDSS.

the tundra/sequoia front diff is an easy swap. You'll need to remove the part time actuator and swap over the cruiser parts.

4.3 help out the driveline with 35s. 4.88 would be better for towing.
 

supercarrera

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Hi @TeCKis300 if you have time can you document the process with pictures. I think I'm going this route too but with a locked rear diff. I wanted 4:88s but for the cost savings, the 4.30s are difficult to pass up. I've R&R'd my 80 diffs a couple times and it was pretty easy but I've never dealt with an IFS front before and the rear looks more complicated than the 80 too.
 

KLF

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Only advice I can add is when you get the install kits, remove the pinion seal and throw it directly into the trash. I never installed aftermarket seals. Get the OEM seals, once you put them side by side you'll see the difference.
 
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Hi @TeCKis300 if you have time can you document the process with pictures. I think I'm going this route too but with a locked rear diff. I wanted 4:88s but for the cost savings, the 4.30s are difficult to pass up. I've R&R'd my 80 diffs a couple times and it was pretty easy but I've never dealt with an IFS front before and the rear looks more complicated than the 80 too.

Yup. That's the intent. I've got some good knowledge of what needs to be done but it's been collected piecemeal. Will try my best to capture the key portions.


The 99-2000 factory locker is not compatible with the landcruiser sway bar.
The electrical actuator would interfere.
It may work with the lexus without KDSS.

the tundra/sequoia front diff is an easy swap. You'll need to remove the part time actuator and swap over the cruiser parts.

4.3 help out the driveline with 35s. 4.88 would be better for towing.

Throwing down some great nuggets of info there... :bounce:

Didn't know that the front Tundra donor carrier could potentially be a drop in with minor external parts swap. That would simplify this greatly. Would just need a couple side axle seals to refresh and it could slip right in with minimal labor.

The Tundra front carrier bits makes for another interesting possibility. Part time 4WD trucks like the Tundra use an auto disconnecting differential (ADD) mechanism. Akin to manual hubs in function, but unlocks via an actuator in a side shaft. This addition could be a novel poor mans 2WD mode with it disengaged, while locking the center diff. I'll play with this idea when I'm under there. Unless nothing of that extended side shaft/ADD actuator fits.

My thought process for 4.3s came down to two reasons
1) OEM gears
2) My current setup with 33s and stock gearing, has 7% gearing loss relative to stock. I tow close to the max gross combined vehicle weight of 14,645lbs and she still hauls the mail. Having practically stock gearing with 35s and 4.3s, (or 3% better than stock with 33s), will give me back all I need. 4.56 IMO if there were such a thing (in OEM) would be awesome.
 
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TexAZ

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I made the swap a couple years ago when I went from 285/75/17 to 35s.

It totally changes the driving/braking feel of the truck.
I tow a 4000 lb boat. It has helped get from 5 mpg to 7....woo hoo! More of an aerodynamic issue for me.

I've debated getting stock tundra rims (cheap) and small stocker size tires just to see how it helps towing.
And admittedly, I'd love to romp on some.little pizza cutters with these gears.
 
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You should be able to drop the LX470 rear third member into your rear axle as well, I believe. Unless you are really wanting to install the locker, you could swap the diffs in in a weekend and be ready to go. Do you know the mileage on the diffs you bought?
 

bloc

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Following this closely, as OEM 4.33 and possibly 4.56 were high on my radar. I’ve read too many bad things about how all of the aftermarket options break in. @bjowett seems to have earned a reputation for being the “factory gears in x.xx ratio” guru.. is a genuine toyota 4.56 available for our diffs?

The 99-2000 factory locker is not compatible with the landcruiser sway bar.
The electrical actuator would interfere.
It may work with the lexus without KDSS.

Is it an issue with just the actuator? I see someone mentioned replacing the actuator with an air piston. Any input on whether we could work around the bar with a different shape of actuator? I’ve also seen manual cable conversions on early minitruck axles..
 
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There are many ratios available for the 9.5", including 4.56. It sees use in many of Toyota's vehicles. The problem is the front diff, I believe 4.30 is the largest.

Harrop just released the E-Locker 4, most of the negatives of their earlier designs, have been addressed. I'm leaning towards it for future projects.
 

TexAZ

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The 80 series guys came up with an air actuator to replace the problematic electric actuator. It is very small and clears the sway bar. It's been a while since I messed with it. I'll see if I can dig up the parts list.
 
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You should be able to drop the LX470 rear third member into your rear axle as well, I believe. Unless you are really wanting to install the locker, you could swap the diffs in in a weekend and be ready to go. Do you know the mileage on the diffs you bought?

Plot thickens again in a great way. All these things drop in? Why haven't we all been doing this years ago! Thanks for the info.

Mileage
- '02 LX470 diff - 168k. Harder to find low mileage with these older parts. The gears look incredibly fresh. No real perceptible wear so far as I can tell, and the pre-load on everything is tight as a drum. I will likely rebuild this anyhow with my own carrier once I get the Harrop in.
- '12 Tundra diff - 72k miles. Thing is clean as a whistle. I won't hesitate to drop this right in as it has 50k less miles than my axle.

Shipping on these steel lumps can be a doozy, possibly freight. Lucked out on the front axle as the carrier shipped it free inter-network, at a drop point only a few miles from my house :)

There are many ratios available for the 9.5", including 4.56. It sees use in many of Toyota's vehicles. The problem is the front diff, I believe 4.30 is the largest.

Harrop just released the E-Locker 4, most of the negatives of their earlier designs, have been addressed. I'm leaning towards it for future projects.

E-locker 4? Do you know when the new design ships? Seems the current Harrops are back-ordered.
 

grinchy

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After using 4.88 for about a year now, I don't see any drawback to this ratio. The mild increase in high speed (80 mph+) RPM over say a 4.56 or 4.33 (maybe 100 rpm?) isn't enough into the RPM range to increase engine noise at all (and at those speeds there are other noises that are louder). But the torque available low in the RPM range is much improved. I see the concern about the Nitro gears, and did have some wear in shavings at the 500 mile break in change. There was also some 'gear noise' for a few thousand miles. I'm up around 8000 to 10000 miles on the gears (I'll go double check that) and now they are silent as the factory drivetrain was (or at least my recall of that drivetrain). I certainly don't notice anything out of the ordinary in use.

I know OP has locked in on 4.33 for many good reasons, just putting this here for the ratio discussion.

@TeCKis300 Nitro was selling an alternative eLocker when I geared up. It locks up good. Can't find it on their site, but if you want a second option you could reach out to them. It's an Auburn part, in the eCTDMax line, and runs open/locked.
 
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How available is a e-locked rear on the salvage market? I would assume tough to get as they were pretty limited in the US market. Harrop is a better design although significantly more expensive plus additional setup.
 
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It’
Plot thickens again in a great way. All these things drop in? Why haven't we all been doing this years ago! Thanks for the info.

Mileage
- '02 LX470 diff - 168k. Harder to find low mileage with these older parts. The gears look incredibly fresh. No real perceptible wear so far as I can tell, and the pre-load on everything is tight as a drum. I will likely rebuild this anyhow with my own carrier once I get the Harrop in.
- '12 Tundra diff - 72k miles. Thing is clean as a whistle. I won't hesitate to drop this right in as it has 50k less miles than my axle.

Shipping on these steel lumps can be a doozy, possibly freight. Lucked out on the front axle as the carrier shipped it free inter-network, at a drop point only a few miles from my house :)



E-locker 4? Do you know when the new design ships? Seems the current Harrops are back-ordered.

I think that’s the beauty of the 4.30 ratio diffs. Other than swapping the part time actuator on the front I think they’ll drop right in. That’s what I would do personally, and I’ve considered doing that. If you’re going to the trouble of rebuilding the diffs, I’d jump right to 4:56 with new gears/bearings, etc.
 

supercarrera

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Where did you source your parts? Ebay? Local wrecking yard?
 

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