DIY 4.3 Re-Gear (4 Viewers)

[lx200inAR]

So, would the 3rd member from a 4.7 or 4.6L Tundra be a drop in since they used the 9.5" axle? With the 2016+ 8 speed trucks having a factory 3.31 ratio, the 3.91's from the Tundra 4.6L would be pretty mint with a 35" tire, or even a 37. Even with a 37", they would still be slightly shorter overall than the stock 3.31/32" tire combo.

1st gear would be shorter than the 6 speed trucks with 4.88's, but 8th would still be decently tall for the freeway. I figure it would be at 2000 rpm running at 75mph with a 315/70R17

Pretty sure 3.91 is the common upgrade for 2016 and later. 3.91 is also the ratio for all the pre 2016 200 series (LX and LC). So the ideal option is to source parts from a pre 2016 that had it's gears updated to 4.30 or 4.88. I think there's some weird stuff that happened at some point for the post 2016 with the axle carriers. But i don't know the details, so more homework would be necessary.

 

[bloc]

I think there's some weird stuff that happened at some point for the post 2016 with the axle carriers. But i don't know the details, so more homework would be necessary.

IIRC as the ratios got taller and taller the pinion gear got larger and as a result the ring gear got thinner.. to the point Toyota just moved the ring gear flange sideways to allow a thicker gear.

 

[skrypj]

Pretty sure 3.91 is the common upgrade for 2016 and later. 3.91 is also the ratio for all the pre 2016 200 series (LX and LC). So the ideal option is to source parts from a pre 2016 that had it's gears updated to 4.30 or 4.88. I think there's some weird stuff that happened at some point for the post 2016 with the axle carriers. But i don't know the details, so more homework would be necessary.

Yeah I just figured the Tundra 3rd members would probably be a hell of a lot easier to find than a LC/LX 3rd. Normally the tundy would have the 10.5" axle but the 4.7/4.6's came with the 9.5" and the 3.91's so its an easy swap.

Car-part.com has a few locally even.

 

[bloc]

Yeah I just figured the Tundra 3rd members would probably be a hell of a lot easier to find than a LC/LX 3rd. Normally the tundy would have the 10.5" axle but the 4.7/4.6's came with the 9.5" and the 3.91's so its an easy swap.

Car-part.com has a few locally even.

I don't think they work.. The 3.9 gears from each platform are different part numbers, and if they shared the rest of the architecture I don't know why they'd change these.

Really, none of the part numbers carry over. The housing, diff carrier, all different parts. To me this suggests its just a different part family than for our rigs.

 

[skrypj]

I don't think they work.. The 3.9 gears from each platform are different part numbers, and if they shared the rest of the architecture I don't know why they'd change these.

Really, none of the part numbers carry over. The housing, diff carrier, all different parts. To me this suggests its just a different part family than for our rigs.

possibly. But Eaton shows same diff carrier P/N for the 200 and 4.7L Tundra so they cant be that different.

And I have seen a couple of site list gears as compatible with both.

 

[bloc]

possibly. But Eaton shows same diff carrier P/N for the 200 and 4.7L Tundra so they cant be that different.

View attachment 3557707

And I have seen a couple of site list gears as compatible with both.

Good info. Someone needs to put them side by side.

 

[CanadianRockyCruiser]

sweet victory over the bearing. The feet on this puller would mar the mating surface. A few 2x4 cutoffs provided stability and enough softness to keep the aluminum shell unscathed.

This puller was ~$70CAD on Amazon...the slide hammer didn't want to move it at all, but the puller was smooth like butter.

BTSHUB Blind Bearing Puller Tool Set Blind Hole Remover Inner Internal Bearing Extractor Set 8-58mm Collets Size https://a.co/d/7uTlfdK

I ordered a 100 series rear 3rd member new out of Japan on IMPEX for $940USD. Figure I'll keep the 200 series differentials that I pull from my LX570, in case I ever want to add lockers and (different) gears to those in the future.

 

[bjowett]

I ordered a 100 series rear 3rd member new out of Japan on IMPEX for $940USD. Figure I'll keep the 200 series differentials that I pull from my LX570, in case I ever want to add lockers and (different) gears to those in the future.

Which number 100 series diff did you order? They usually supersede out to a 200 number.

 

[CanadianRockyCruiser]

Which number 100 series diff did you order? They usually supersede out to a 200 number.

41110-60A31

Should fit... I hope?

 

[bjowett]

Yes, it will fit. That is the superseded number.