High Pinion Toy 8" build up

Jody Treadway

Jody Treadway

Croc wearing fool
Moderator
Joined
Mar 20, 2005
Location
Hendersonville, NC
I built this diff for the first time about 6 years ago. The owner wheels *almost* as hard as @CasterTroy. Toyota buggy on 38.5 SXs on the hardest trails in the south. Eventually, things wear out. He lost the majority of 3 teeth on the ring and jacked a few pinion teeth.
Time for a rebuild.
Started with a teardown and clean. Pressed in new races and set the empty third in my workbench diff stand.
Sat out the drop-out third member specific axle tools I use. A big ass spanner and a flange holder. Not the prettiest, but as you'll see in the next post, works just fine.
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I like to measure and label Toy shims. Dana shims are all common thicknesses. 2.5, 5, 10, 20 and 30 thou. You actually tell them apart by their rigidity. Yota shims in this case are between 10-18 thou with a few master 50s mixed in. Doing this now will keep your micrometer clean later
Based on the hundreds of HP8" I've done, I know they use right around 77-80 thou usually. I started at 0.078" initially. Pressed on the bearing and began stacking the crush sleeve eliminator. I have found adding around 0.050" to the eliminator gets me close. Nailed it again. I used the flange holder to hold it stationary while I tightened it to spec (ugga, ugga).
More to come in next post.
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Pinion preload was set (22 in/lb rotational torque) so it was time to drop in the welded carrier. Apply anti seize to the adjusters first before the caps. Be very careful not to cross-thread the adjusters as that will wreck the housing, cap and adjusters.
Once satisfied with the alignment, I threaded out the non ring gear side (NRG) and began threading IN the ring gear side (RG) until the point of zero backlash, but where you can still rotate the assembly. Once at zero, smack the ring gear away from pinion with the dead blow to seat the bearing. This will always open up the BL a hair. Then readjust to zero again.
Now it's time to add preload and backlash with the big red spanner. I use the spanner to tighten the NRG adjuster applying my body weight until one of the alignment holes lines up with the lock wedge. After doing so, sure enough, 0.007" BL was attained. Preload felt good as the ring and pinion spun freely via the flange.
Next up, pattern evaluation.
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Knowing the gear set is installed with shimming I've historically used with great results, preload feels good and overall rotation feels smooth, let's paint some teeth
As you can see, the coast side is beautiful. Centered front to back, top to bottom. A very broad contact patch that is gradual in every way. The drive side is all of the above, maybe just marginally deep, by like 2-3 thousanths.
However, if I took away pinion depth to improve drive, the coast side would be too close to the top edge of the tooth for my taste. I want the owner to not think twice about backing uphill with all the weight on the front. For these reasons, I left it alone. Any change would sacrifice an already acceptable and strong setup on either drive or coast.
All said and done, these Nitro 5.29 gears, flange and CSE went together very well and will give many years of trouble free service.
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paradisePWoffrd said:
Would the process for a low pinion be much different?
Click to expand...
Not really. Only consideration would be whether it was being used in the front or rear. If up front, i would subtract 1-2 thou on backlash and set it up just a hair deeper. I do this to account for deflection under load.
 
junkxj said:
Any difference between them and an open carrier, in relation to setting up the gears?

The reason I ask, is because I can not find anyone local that will set up a new gear set once I mention the elocker.
Click to expand...
There's absolutely nothing different. Having an elocker, spool, ARB, etc doesnt change a thing.
Drop it in a 5 gallon bucket and ship it my way. I'll hook it up
 
Jody Treadway said:
There's absolutely nothing different. Having an elocker, spool, ARB, etc doesnt change a thing.
Drop it in a 5 gallon bucket and ship it my way. I'll hook it up
Click to expand...

I honestly didn't think it would, but never having these axles apart, I wasn't sure.
I would imagine you have also done the 9.5 ff rear also? If so, I will be happy to send them your way.
 
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