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Currie FJ Ford 9 Axle
As we know the FJ aftermarket is oversaturated in the suspension department, but almost no products are available for the driveline. We are breaking spindles, links and a number of us are breaking gears.
For those new to rear ends (as I am), the stock 8.4" Toyota ring and pinion is just too small for the way we are using it. There have been many broken ring and pinions - I read about one Moab run where 10% of the FJs broke theirs. We like to load up with a lot of cargo and big tires, and when wheels hop on the rocks that's it.
Currie will release a Ford 9-inch axle for the FJ, a must-have item for many of us. This gives us two state of the art choices in rear axles, including the new All-Pro/Currie Dana that just came out. This is about my day there and what I learned about this new product for the FJ.
To oversimplify, there are two primary aftermarket gear sets for factory offroad vehicles. The Dana series for crawlers, and the Ford 9 for racers. Dana pinions are 2 inches above the rear axle, and the Ford 9 is two inches below. So who wants a Ford 9? It's stronger and takes the sudden shock loads of high-speed runs better. But that clearance creates an issue over the rocks.
Dave Castillo called me to come in and let him take some measurements. He is the product designer, and just finished up working with Jon at All-Pro to develop the All-Pro/Currie Dana Rock Jock axles for the FJ. Mine will be the prototype Ford 9, made on the same fixture the All-Pro Dana is made on.
![]()
Currie is THE name in rearends, dating back to the fifties. Here is their huge building in Anaheim.
![]()
Row after row of the new All-Pro Currie Dana axles ready for shipment.
![]()
Every rear-end related item you can think of, manufactured in-house for just about every performance car and truck out there.
![]()
Dana displays for Jeep. The Rock Jock rear on the right looks very similar to the All-Pro axle.
![]()
A small portion of their industrial-quality manufacturing shop.
![]()
Waiting for paint after assembly. A Ford 9 is second from the front.
![]()
A final JK rear axle. Never thought I would admire a rear axle for build quality, finish and aesthetics, but they really look great.
![]()
And there's the patient! The first-ever Ford 9" for the FJ in Dave Castillo's fixture.
![]()
Currie Track-9 is the NASCAR standard almost without exception. This is the heaviest housing of the Track-9 series, from 26 to 18 lbs.
Housings and covers are formed from high tensile (High Form 50/Spec A715) steel. This material is 39% stronger than conventional 1010 low carbon steel. So it's halfway between mild steel and Chromoly in strength.
![]()
Currie was clever enough to improve on the FJ's delicate shock mounts. They rotated the lower shock pin 90 degrees so that it gains almost an inch in ground clearance without reducing travel. You will notice that the bracket here is 90 degrees to the stock one.
![]()
This fixture will be moved off the test bench and into production when the final measurements are taken off my stock axle. Right now all the brackets are tacked into place and will probably be adjusted slightly.
![]()
Custom CNC large-bearing housing ends just for the FJ.
![]()
Now it was time to make sure this axle fits the FJ properly. So up on the lift and get out the measuring tape.
![]()
![]()
![]()
My stock housing, mere weeks away from its next explosion, was still too hot to touch. This is because my tweaked ring and pinion are trying to destroy each other and creating a lot of friction in the process.
They said the oil leak is because the front cover has been shrinking and expanding from the heat, and that has wrecked the seals over time.
![]()
On the left is a stock Tacoma axle like we have, and on the right is the blank for their FJ axle. It looked about .25" larger but I did not have calipers. They will cut it to length, drill the lug pattern in the end, and cut the 35 splines on the skinny end.
The one bit of bad news is that they want me to get a driveshaft too. Apparently the Ford yoke doesn't match up with the Toyota one. However, I bet they can come up with a fix for this once the axle is finalized into a real product.
Next week they will call me in to install it. It'll be nice to not worry about blowing up the rear end, and it will be a lot quieter on the freeway without the whining of gears locked in mortal combat with each other.
As we know the FJ aftermarket is oversaturated in the suspension department, but almost no products are available for the driveline. We are breaking spindles, links and a number of us are breaking gears.
For those new to rear ends (as I am), the stock 8.4" Toyota ring and pinion is just too small for the way we are using it. There have been many broken ring and pinions - I read about one Moab run where 10% of the FJs broke theirs. We like to load up with a lot of cargo and big tires, and when wheels hop on the rocks that's it.
Currie will release a Ford 9-inch axle for the FJ, a must-have item for many of us. This gives us two state of the art choices in rear axles, including the new All-Pro/Currie Dana that just came out. This is about my day there and what I learned about this new product for the FJ.
To oversimplify, there are two primary aftermarket gear sets for factory offroad vehicles. The Dana series for crawlers, and the Ford 9 for racers. Dana pinions are 2 inches above the rear axle, and the Ford 9 is two inches below. So who wants a Ford 9? It's stronger and takes the sudden shock loads of high-speed runs better. But that clearance creates an issue over the rocks.
Dave Castillo called me to come in and let him take some measurements. He is the product designer, and just finished up working with Jon at All-Pro to develop the All-Pro/Currie Dana Rock Jock axles for the FJ. Mine will be the prototype Ford 9, made on the same fixture the All-Pro Dana is made on.
Currie is THE name in rearends, dating back to the fifties. Here is their huge building in Anaheim.
Row after row of the new All-Pro Currie Dana axles ready for shipment.
Every rear-end related item you can think of, manufactured in-house for just about every performance car and truck out there.
Dana displays for Jeep. The Rock Jock rear on the right looks very similar to the All-Pro axle.
A small portion of their industrial-quality manufacturing shop.
Waiting for paint after assembly. A Ford 9 is second from the front.
A final JK rear axle. Never thought I would admire a rear axle for build quality, finish and aesthetics, but they really look great.
And there's the patient! The first-ever Ford 9" for the FJ in Dave Castillo's fixture.
Currie Track-9 is the NASCAR standard almost without exception. This is the heaviest housing of the Track-9 series, from 26 to 18 lbs.
Housings and covers are formed from high tensile (High Form 50/Spec A715) steel. This material is 39% stronger than conventional 1010 low carbon steel. So it's halfway between mild steel and Chromoly in strength.
Currie was clever enough to improve on the FJ's delicate shock mounts. They rotated the lower shock pin 90 degrees so that it gains almost an inch in ground clearance without reducing travel. You will notice that the bracket here is 90 degrees to the stock one.
This fixture will be moved off the test bench and into production when the final measurements are taken off my stock axle. Right now all the brackets are tacked into place and will probably be adjusted slightly.
Custom CNC large-bearing housing ends just for the FJ.
Now it was time to make sure this axle fits the FJ properly. So up on the lift and get out the measuring tape.
My stock housing, mere weeks away from its next explosion, was still too hot to touch. This is because my tweaked ring and pinion are trying to destroy each other and creating a lot of friction in the process.
They said the oil leak is because the front cover has been shrinking and expanding from the heat, and that has wrecked the seals over time.
On the left is a stock Tacoma axle like we have, and on the right is the blank for their FJ axle. It looked about .25" larger but I did not have calipers. They will cut it to length, drill the lug pattern in the end, and cut the 35 splines on the skinny end.
The one bit of bad news is that they want me to get a driveshaft too. Apparently the Ford yoke doesn't match up with the Toyota one. However, I bet they can come up with a fix for this once the axle is finalized into a real product.
Next week they will call me in to install it. It'll be nice to not worry about blowing up the rear end, and it will be a lot quieter on the freeway without the whining of gears locked in mortal combat with each other.
I will never hit 40 I will stay young forever. 
