Diff questions

[ShottsUZJ100]

The 80 series gearset is not any weaker.

There is a reason why:

On a 100-series WITHOUT the V8 the gearset is the same as the 80-series

On a 100-series WITH the V8 the gearset has more splines and is thicker and larger.

While the 80-series gearset is PROBABLY strong enough for the V8 100, I personally will not take that gamble with my drivetrain. Others have and more may also. I'll wait.

**There must have been a reason Toyota beefed up the rear gears in the UZJ. I'll stick with Toyota despite not knowing their reasoning.

 

[sleeoffroad]

John

with 4.88's the pinion becomes smaller and the ring gear bigger. So if anyone makes gears for it, it will not be the same strength as the 4.30's. There is no proof that the 100 gears are stronger. Yes the desing is slightly different and I believe I posted pictures before, but there was no indicaction that they are stronger.

Your statement above is not correct. The axle splines are 32 spline, and these you retain when using the 80 gears to regear.

Carl would know about gears, he works for one of the leading suppliers of gears in the country.

105 uses a 80 series axle, 100 uses a semi floater. Yes, the axle shafts are larger and that might be because of the v8.

So what is better. Lugging your tranny to get over rocks when the gear ratio is to big, or a supposed "weaker" gearset? All I can say is that since my crawler box is working on my ShortBus I have not broken a axle or birfield and I have been in places where I would have before. Gearing takes a lot of stress out of the drivetrain since you can drive the same obstacle at lower rmps (so less hp applied to the drivetrain). This migth not be the case with a manual tranny, but with the automatic, you have to get the motor spooled to get going. With lower gears you have more control.

I said this before, there are other parts you are going to break before you break a rear ring and pinion.

 

[ShottsUZJ100]

John

with 4.88's the pinion becomes smaller and the ring gear bigger. So if anyone makes gears for it, it will not be the same strength as the 4.30's. There is no proof that the 100 gears are stronger. Yes the desing is slightly different and I believe I posted pictures before, but there was no indicaction that they are stronger.

Your statement above is not correct. The axle splines are 32 spline, and these you retain when using the 80 gears to regear.

Carl would know about gears, he works for one of the leading suppliers of gears in the country.

105 uses a 80 series axle, 100 uses a semi floater. Yes, the axle shafts are larger and that might be because of the v8.

So what is better. Lugging your tranny to get over rocks when the gear ratio is to big, or a supposed "weaker" gearset? All I can say is that since my crawler box is working on my ShortBus I have not broken a axle or birfield and I have been in places where I would have before. Gearing takes a lot of stress out of the drivetrain since you can drive the same obstacle at lower rmps (so less hp applied to the drivetrain). This migth not be the case with a manual tranny, but with the automatic, you have to get the motor spooled to get going. With lower gears you have more control.

I said this before, there are other parts you are going to break before you break a rear ring and pinion.

ALL MAKES TOTAL SENSE!

I'm (me, just me) and not comfortable swaping the parts. I'll wait. Plus I'm building that LX!

 

[Pskhaat]

As I'm new to the 100, what do you use in the front for gears then? Are there other carriers or are these gears easy to come by vs. the rear?

 

[ShottsUZJ100]

As I'm new to the 100, what do you use in the front for gears then? Are there other carriers or are these gears easy to come by vs. the rear?

Same as an 80

 

[montocr]

100 gears

John,
It is funny how sure you are about things that you know very little about. Having been one of few people here who have actually seen the gears side by side, I can tell you that the 100 gear is thicker thus allowing it to be threaded for r/g bolts, rather than through bolts. The added material is not the teeth, and the pinion spline count is not different. If you are so concerned with Toyota doing this "for a reason", than why don't you run the stock tires that were used for "a reason", or why do Sequoias use a 7.5" diff up instead of an 8" like the L/C? The benifits of a gear change outweigh any disadvantages.

 

[Pskhaat]

You can open up the front diff carrier and use the 8" r&p gears from an 80? The housing's will accept them? Pinion shaft splines match too? I'm assuming it's reverse cut also.

 

[ShottsUZJ100]

John,
It is funny how sure you are about things that you know very little about.

If you are so concerned with Toyota doing this "for a reason", than why don't you run the stock tires that were used for "a reason", or why do Sequoias use a 7.5" diff up instead of an 8" like the L/C? The benifits of a gear change outweigh any disadvantages.

It's OK for me to opt for the "conservative" decision regarding this.

My driveline operates like new, and the truck performs on and off-road extremely well. Therefore, it's not worth the risk (however large or small it may be) for ME (ME, is the key) to make the swap.

As for tires, and other "changes"? I've weighed the pros and cons and opted for larger tires and other various mods. Considering the result I can see I've done a fine job on this truck.

I'm thrilled I tried 80-series L-shocks onto the 100. They work SUPERBLY and others accross the US I'm sure will follow!

 

[calamaridog]

John--looks like Marks4wd has extra low transfer case gears in the works. Might even be available already. Stock is 2.488:1 this one will be 3.115:1 for a 25% reduction.

http://www.marks4wd.com/lc-80-100-extra-low-tc-gears.htm

Not only do they offer the lower gears, they also offer the cruiser crawler box. The only problem is the crawler box doesn't work with IFS transfer cases due the the crossmember for the torsion bar being in the way.

This is why I want to eliminate the damn torsion bars and swap in some coilovers.

Advanced Adapters can special order their products for those of us in the U.S.

 

[hoser]

It "appears" the 25% reduction transfer case gears are available as there is now pricing on the website. "RRP $1195 inc GST in Australia." Not sure how much Advance Adapters could get it for.

http://www.marks4wd.com/lc-80-100-extra-low-tc-gears.htm

 

[calamaridog]

I emailed Advanced Adapters and asked for a price on the Gears and the Crawler. I also asked if we could get a group buy on 5 or more of the lower gears. I'll let you know what they say.