Why did Toyota get rid of the 9.5" front diff for the 80 series? (2 Viewers)

[OGBeno]

The 70 series (heavy duty iterations) went to the same birfields as the 80 series at the same time. There is logic in what Toyota did across the wagons and the heavy duty 7x series trucks.

Then, in 1998, 7x series trucks went to the 10mm hub studs, front and rear, just like the 100/105 series. Again, showing that small incremental changes to engineering architecture are hallmarks of the design process for the Land Cruiser series (especially the heavy duty/wagon versions). Differential parts/bearings/gear ratios also changed for both platforms (based on powertrain/driveline options, platform and market-based).

 

[SNLC]

FYI, you can bolt on 105-series hubs to an 80 housing. These hubs have bigger lug studs and bigger hud stud/dowels.

Cheers

 

[Broski]

I read this entire thread up to here and there has been zero reliable theories/info posted save post #10 which addresses the original question. I've broken random bits including rear nitro shafts but never an RCV and never hub studs, front R&P, cracked Aisin hub gears (37's and air lockers). Over the years many have reported failures of every single part and component of these 80 series axles. One guy snaps hub studs twice in a day running stock hardware on 35's while the next guy explodes a front diff running Aisin hubs that most think will give up first (which i've also seen) and then there's the guy that manages to destroy two front RCV axles simultaneously while the diff and flanges are unharmed. Anything can happen on any given day spent running rugged terrainincluding the demise of 9.5 diff's which I've also seen on trail.

A question I've asked myself is; why did Toyota go to a smaller diff and much larger Birf's in the same design change? Is the 80 that much heavier or that much more powerful than it's predecessors?? Pairing a theoretically weaker diff (based on less material used and leverages involved) with considerably stronger knuckles/Birf's???????????

Very well said Steve !

 

[Marvelicious]

I read this entire thread up to here and there has been zero reliable theories/info posted save post #10 which addresses the original question.

Okay, well... If it's a serious question, here it is: they made that call for the same reason car companies make every decision: they considered weight, packaging, reliability and most importantly cost. They made the compromise they thought was acceptable. If I had to guess, I'd say they felt the high pinion center was strong enough while being easier to fit, lighter and most importantly, using less materials to produce.

We like to think that they spared no expense and built us the best possible vehicle they could, but that just isn't the case. Toyota pulled out all the stops once when the built the LFA. I doubt many of us have LFA money. Even if cost wasn't an object you still have to balance weight, packaging and strength. Building a car is a series of compromises.

 

[matzell]

They may have compared the strength of a RR front 8" to a low pinon front 9.5 driven on the coast side and found that it was almost as strong? But knew the Birfs were weaker. Just a thought. as well as packaging discussed before.

 

[OGBeno]

Okay, well... If it's a serious question, here it is: they made that call for the same reason car companies make every decision: they considered weight, packaging, reliability and most importantly cost. They made the compromise they thought was acceptable. If I had to guess, I'd say they felt the high pinion center was strong enough while being easier to fit, lighter and most importantly, using less materials to produce.

We like to think that they spared no expense and built us the best possible vehicle they could, but that just isn't the case. Toyota pulled out all the stops once when the built the LFA. I doubt many of us have LFA money. Even if cost wasn't an object you still have to balance weight, packaging and strength. Building a car is a series of compromises.

Well said. And 100% true. Especially for cost reasons, especially for Toyota.

 

[SaturnAscends]

Okay, well... If it's a serious question, here it is: they made that call for the same reason car companies make every decision: they considered weight, packaging, reliability and most importantly cost. They made the compromise they thought was acceptable. If I had to guess, I'd say they felt the high pinion center was strong enough while being easier to fit, lighter and most importantly, using less materials to produce.

We like to think that they spared no expense and built us the best possible vehicle they could, but that just isn't the case. Toyota pulled out all the stops once when the built the LFA. I doubt many of us have LFA money. Even if cost wasn't an object you still have to balance weight, packaging and strength. Building a car is a series of compromises.

Yea from what other people have said, it sounds like they would’ve had to put the steering in front of the axle to fit the 9.5” with the coil springs, and at that point they might as well have just linked the front axle like a Patrol. But I think they were prioritising serviceability, durability, and cross-platform standardisation over suspension travel and technical off-roading ability. I’m not sure “rock-crawling” was even a thing back in the 80s and 90s; it must have been more niche than it is now at least.

 

[baldilocks]

Okay, well... If it's a serious question, here it is: they made that call for the same reason car companies make every decision: they considered weight, packaging, reliability and most importantly cost. They made the compromise they thought was acceptable. If I had to guess, I'd say they felt the high pinion center was strong enough while being easier to fit, lighter and most importantly, using less materials to produce.

We like to think that they spared no expense and built us the best possible vehicle they could, but that just isn't the case. Toyota pulled out all the stops once when the built the LFA. I doubt many of us have LFA money. Even if cost wasn't an object you still have to balance weight, packaging and strength. Building a car is a series of compromises.

You got a resume of qualifications to put down here?

 

[Marvelicious]

You got a resume of qualifications to put down here?

Do I need one to point out the obvious? It's an internet forum, I could claim to be an engineer working for Toyota and it wouldn't have any more validity than anything else. What's your issue? Do you think Toyota isn't considering those factors? It should be fairly apparent considering the fact that the frame isn't chromoly and the engine isn't powered by unicorn farts.

Yea from what other people have said, it sounds like they would’ve had to put the steering in front of the axle to fit the 9.5” with the coil springs, and at that point they might as well have just linked the front axle like a Patrol. But I think they were prioritising serviceability, durability, and cross-platform standardisation over suspension travel and technical off-roading ability. I’m not sure “rock-crawling” was even a thing back in the 80s and 90s; it must have been more niche than it is now at least.

Right on all counts. Rock crawling certainly wasn't the sport it is now... wheeling enthusiasts were a thing, but I'm pretty sure "rock crawling" wasn't even a term until Marlin started building his doublers. I'm pretty sure I first heard the term used in the early to mid 90s, but I'm positive that Toyota didn't look at it as their intended market.

 

[SNLC]

Yea from what other people have said, it sounds like they would’ve had to put the steering in front of the axle to fit the 9.5” with the coil springs, and at that point they might as well have just linked the front axle like a Patrol. But I think they were prioritising serviceability, durability, and cross-platform standardisation over suspension travel and technical off-roading ability. I’m not sure “rock-crawling” was even a thing back in the 80s and 90s; it must have been more niche than it is now at least.

A Patrol is not linked, it is radius arms with a panhard and tie rod behind the axle same as an 80.

Cheers

 

[baldilocks]

Do I need one to point out the obvious? It's an internet forum, I could claim to be an engineer working for Toyota and it wouldn't have any more validity than anything else. What's your issue? Do you think Toyota isn't considering those factors? It should be fairly apparent considering the fact that the frame isn't chromoly and the engine isn't powered by unicorn farts.


Right on all counts. Rock crawling certainly wasn't the sport it is now... wheeling enthusiasts were a thing, but I'm pretty sure "rock crawling" wasn't even a term until Marlin started building his doublers. I'm pretty sure I first heard the term used in the early to mid 90s, but I'm positive that Toyota didn't look at it as their intended market.

You used many words to point out the obvious. Thanks for that.

It’s cool to know that Toyota didn’t need to pull out all the stops to bring us one of the, if not the, most overall durable, reliable, and versatile vehicle ever mass produced.

 

[SaturnAscends]

A Patrol is not linked, it is radius arms with a panhard and tie rod behind the axle same as an 80.

Cheers

Thanks, I must’ve been thinking of a Wrangler.

 

[Broski]

I think that the 8" HP is will suited for it's intended use/tire size.
I don't think that Toyota ever expect the 80 to be a rock crawler running 37,39, and even 40" tires !!
The fact that people are getting away with it is a testament to there strength and durability!

 

[SaturnAscends]

I think that the 8" HP is will suited for it's intended use/tire size.
I don't think that Toyota ever expect the 80 to be a rock crawler running 37,39, and even 40" tires !!
The fact that people are getting away with it is a testament to there strength and durability!

Yea some people are running 40s on them on mini trucks since they’re so light lol

 

[scottryana]

I think the 8" RR is a smart move, I also think it was engineered elegantly for its intended use. I think it is us enthusiasts that drag the 80 into unreliability. Part of it wasn't our fault with the US market only getting fully loaded 80's but a lightweight 80 works better in every way! Once you add heavy bumpers, heavy armor, heavy load outs, etc you put the 8" at risk. If we as enthusiasts want to go that far beyond the 80's intended purpose we need to be ready to accept that we might have to change to parts the 80 has.

 

[Broski]

Yea some people are running 40s on them on mini trucks since they’re so light lol

Dude were talking 80s here !! and there are plenty of them running 39s & 40s, 37s seem to be the norm !!

 

[SNLC]

Thanks, I must’ve been thinking of a Wrangler.

I am no Jeep guy but pretty sure they are also radius arm just a different style.

Cheers

 

[SaturnAscends]

I think the 8" RR is a smart move, I also think it was engineered elegantly for its intended use. I think it is us enthusiasts that drag the 80 into unreliability. Part of it wasn't our fault with the US market only getting fully loaded 80's but a lightweight 80 works better in every way! Once you add heavy bumpers, heavy armor, heavy load outs, etc you put the 8" at risk. If we as enthusiasts want to go that far beyond the 80's intended purpose we need to be ready to accept that we might have to change to parts the 80 has.

It’s similar on the Tacoma world. People stuff 35s in there with a big light, heavy bumpers, front locker, etc., then complain that “IFS is junk!”

Every vehicle has its practical limit. I think the 80 series has the highest limit of any 4x4 platform brought to the US, with an optimal blend of strength, comfort, and capability in stock or near-stock form. I’ve actually wondered why it seems so obligatory to add so much weight to an already heavy truck when weight can be such a hindrance in trails, though.

I am no Jeep guy but pretty sure they are also radius arm just a different style.

Cheers

you could be right. I thought at least the Rubicon was linked in front, but I’m not certain.

 

[Diesel-Runner]

Wranglers have been 4 link front and rear for a while. There are some aftermarket lifts that basically make a radius arm by linking the upper and lower control arms into one arm.

 

[mudgudgeon]

I’m not sure “rock-crawling” was even a thing back in the 80s and 90s; it must have been more niche than it is now at least.

Not as a sport. But landcruisers were built to handle abuse around the farm during the week, tow the wifes horses to the point club on Saturday, drive grandma to church on Sunday. And all in the most remote parts of the world you can think of.

Huge portion of rural Australia in the 80s and 90s was serviced by poorly built barely maintained dirt roads. This was a landcruiser's home turf. Still is.

I think it is us enthusiasts that drag the 80 into unreliability.

I agree.
A lot of us modify and push them beyond what toyota designed for.
Lucky they designed for reliability and durability and comfort in the above settings.