7x Series Front Axle Tech Question - Early vs Late Style

[Will Van]

I have the 3.73 8" and 9.5" gears in stock....

Search results for differential

RADD Cruisers 4WD Ltd. is a British Columbia-based automotive business offering a diverse range of service kits and repair parts for Toyota Land Cruisers as wel

radd-cruisers.shoplightspeed.com

~John

@Radd Cruisers - Just confirming that the 3.73 gears for the 8" high-pinion is 27-spline for the companion flange? A lot of aftermarket gears are 29-spline, but I assume since it is OEM Toyota that it's 27-spline.

Also, could you forward me tracking info? I haven't seen anything regarding my order. Thanks!

 

[Radd Cruisers]

@Radd Cruisers - Just confirming that the 3.73 gears for the 8" high-pinion is 27-spline for the companion flange? A lot of aftermarket gears are 29-spline, but I assume since it is OEM Toyota that it's 27-spline.

Also, could you forward me tracking info? I haven't seen anything regarding my order. Thanks!

The 8" HP gears are 29 spline and use the factory flange. The 9.5" gears are provided with a flange.

Tracking information is available through your eCom account login, and should be sent to you by Canada Post (though there can be glitches in their system), and also it's supposed to be available on PayPal as I am required to provide that information under my vendor agreement with PayPal. Please check your Junk Mail folder.

In the mean time I have re-sent your tracking information via a link to USPS which tends to provide more details once it's in their hands.


~John

 

[Will Van]

Unfortunate turn of events regarding Radd Cruisers. Review in the Classified’s section: Bad Seller - Radd Cruisers - https://forum.ih8mud.com/threads/bad-seller-radd-cruisers.1279396/

 

[Loober]

Like to share my experience with this, I was the other person that purchased the gear sets from Radd Cruisers, have gotten them installed and been driving on them for a couple weeks. First of, I won't comment on the topic that @Will Van started. For me, I was after 3.73 gear sets and that's what I got.

I will speak to the experience of getting them installed and thoughts on how the trucks feels and drives compared to the 4.10s.

EDIT: I personally dislike seeing bad information on threads, I was corrected about my statement that 3.73 gears were not made by Toyota, they were just very hard to find, so let's leave it at that.

Here is another thread on it: 3.73 gears - https://forum.ih8mud.com/threads/3-73-gears.851573/page-2

I removed the thirds and took them to a well known toyota gear installer here in Socal. The front went in fine using a typical install kit. It is 29 spline so I had to purchase aftermarket flange as factory was 27 spline, not a big deal.

They also said that the rear is odd ball and the pinion is 32 spline, which is discussed in thread above. Requiring 200 series bearings and seal, which are not very common and took sometime to source, otherwise everything setup per spec.

Now for the fun part....I LOVE LOVE LOVE how it drives now. More range through each gear, at 75mph I am cruising at about 2600 rpms versus 3000. Best of all it feels like I am in the power band much longer. With more engine load at lower rpms, the turbo spools up quicker, gives it more oomph down low.

I did some 4wd low wheeling, wasn't anything extreme, can't say I felt much of a diff. Later when I need a rebuild, I'll have Georg put the low gears in it.

I am running 33 inch tires, with the low end torque of the diesel, you don't sacrifice much performance, with some skinny 35" tires it might be even better.

So there you go.

 

[Will Van]

Nice! Glad you like the gears.

Toyota never offered 3.73 diff gears. But they did offer 3.70 gears in the early 60 series axles and some diesel 80 series from overseas. The difference between 3.73 and 3.70 is negligible.

As far as the model variations, a 9.5” diff is a 9.5” diff. And an 8” HP is an 8” HP. It doesn’t matter which truck it’s bolted to. And doesn’t matter if it is full float or semi-float. So you could swap used 3.70 gears from a semi-float 9.5” 60 series in the rear, and from an 8” 80 series axle in the front, and accomplish the same thing. Toyota actually has the gears available, they’re just hard to get and expensive.

Either way, glad you like your setup!

 

[FJ73Texas]

I would love to cruise at 2,600 rpm but passing may not be very fun with 3.70 / 3.73 gears. I rarely pass cars anyways though and keep it somewhat slow.

 

[svsisu]

Like to share my experience with this, I was the other person that purchased the gear sets from Radd Cruisers, have gotten them installed and been driving on them for a couple weeks. First of, I won't comment on the topic that @Will Van started. For me, I was after 3.73 gear sets and that's what I got.

I will speak to the experience of getting them installed and thoughts on how the trucks feels and drives compared to the 4.10s.

First some background on the 3.73 gears in respect to Toyota heritage. From my research, Toyota never installed these ratios in the HD 70 series models or the 80s which share drivetrains of 8" HP front and 9.5" FF rear. I believe the 60 series 9.5 are different and do not cross over to the 9.5 FF. The 8" HP came in other toyota models like the pickups and tacomas, so those gearsets are widely available.

So the 3.73 rear set has to be custom made aftermarket as that ratio was never sold by Toyota in any model, closest is 3.90 in the 200 series, which share the same R&P. Marks4wd used to be the main source for these, who probably got them from Drivetech4x4 also.

Here is another thread on it: 3.73 gears - https://forum.ih8mud.com/threads/3-73-gears.851573/page-2

I removed the thirds and took them to a well known toyota gear installer here in Socal. The front went in fine using a typical install kit. It is 29 spline so I had to purchase aftermarket flange as factory was 27 spline, contrary to @Radd Cruisers statement above.

They also said that the rear is odd ball and the pinion is 32 spline, which is discussed in thread above. Requiring 200 series bearings and seal, which are not very common and took sometime to source, otherwise everything setup per spec.

Now for the fun part....I LOVE LOVE LOVE how it drives now. More range through each gear, at 75mph I am cruising at about 2600 rpms versus 3000. Best of all it feels like I am in the power band much longer. With more engine load at lower rpms, the turbo spools up quicker, gives it more oomph down low.

I did some 4wd low wheeling, wasn't anything extreme, can't say I felt much of a diff. Later when I need a rebuild, I'll have Georg put the low gears in it.

I am running 33 inch tires, with the low end torque of the diesel, you don't sacrifice much performance, with some skinny 35" tires it might be even better.

So there you go.

Great information, thanks for the write up.

 

[rick_d]

Actually there are 8"/9.5" 3.73 gears made by Toyota. I also have 3.90 factory gears in my truck for optimal use with 1hdt system although they came in VDJ trucks and the rear 3.90 set is used in Sequoia's or some such.