Midnight Metalworks Rockbox D300

I know the feeling. I am going to tweak the pinion some. Once the RPMs exceeds 2500 , my Jeep is not as smooth running. But under that 2500 rpms around 45 to 50 mph things are smooth.
When I had 33's I got harmonic vibes around 64mph. When I went up to 35's they don't come on till around 70mph. This is another plus to being slightly undergeared. My pinion and caster have been in every conceivable angle and I can't dial them out. The only solution is hubs. Right now they're about $1550. I think I can live without them. Who wants to travel over 70 anyway?! If someone drops a bucket of money on me, I might spring for the hubs.
 
When I had 33's I got harmonic vibes around 64mph. When I went up to 35's they don't come on till around 70mph. This is another plus to being slightly undergeared. My pinion and caster have been in every conceivable angle and I can't dial them out. The only solution is hubs. Right now they're about $1550. I think I can live without them. Who wants to travel over 70 anyway?! If someone drops a bucket of money on me, I might spring for the hubs.
I still have to determine where the vibs are coming from around 55 mph.
Torque converter or exhaust or rear pinion angle ….
 
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When I had 33's I got harmonic vibes around 64mph. When I went up to 35's they don't come on till around 70mph. This is another plus to being slightly undergeared. My pinion and caster have been in every conceivable angle and I can't dial them out. The only solution is hubs. Right now they're about $1550. I think I can live without them. Who wants to travel over 70 anyway?! If someone drops a bucket of money on me, I might spring for the hubs.
Have you tried adjusting the pinion down?

I too couldn’t eliminate my vibrations. I finally bought and installed a hub kit. After installing I adjusted my pinion down to allow more caster. My vibs are 99.9999 percent gone with hubs locked in. Of course they are 💯 gone with hubs unlocked. But was a big difference. Can try to adjust down a bit and see if it goes away. Might work, might not…
 
Have you tried adjusting the pinion down?

I too couldn’t eliminate my vibrations. I finally bought and installed a hub kit. After installing I adjusted my pinion down to allow more caster. My vibs are 99.9999 percent gone with hubs locked in. Of course they are 💯 gone with hubs unlocked. But was a big difference. Can try to adjust down a bit and see if it goes away. Might work, might not…
I tried -2*, -1*, 0, 1*, 2*.

Results were the same across the spectrum. 😒 I think this is where I left it.

B30BFED2-DF27-4309-A6BB-E61865CCBB42.jpeg
 
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Have you tried adjusting the pinion down?

I too couldn’t eliminate my vibrations. I finally bought and installed a hub kit. After installing I adjusted my pinion down to allow more caster. My vibs are 99.9999 percent gone with hubs locked in. Of course they are 💯 gone with hubs unlocked. But was a big difference. Can try to adjust down a bit and see if it goes away. Might work, might not…
Never really messed with the front pinion angle. Probably wouldn’t hurt to have an alignment done.
 
My buddy has one of these ready to build for his 4BT YJ. After exploding a couple Dana 300 cases he thought this might be the solution. I can tell you, it is literally metal art and beefy even though its a smaller footprint. Waiting for gears now.

Also, he picked up a new Atlas for his wife's rig today for $2500 local. Lucky dude.

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If he has exploded a couple cases he might be due for an Atlas or a NP205.
Hopefully the billet case holds up for him.
 
If he has exploded a couple cases he might be due for an Atlas or a NP205.
Hopefully the billet case holds up for him.
Its the turbo he has on the 4BT, too damn big. The 300 case is pretty thin to put up with that much torque. The Atlas is going behind an LS that has a 300 already. It was going to need a flip for the SD axle from the passenger drop 44 it had. Just worked out cheaper this way. I think the Rockbox will hold up. Compared to a 300 case its thicker and better material.
 
I can break a 231 every couple of weeks before I hit $3500.

-Mac

You are missing the point. And we all spend tons of money needlessly on our rigs as it is.

Can a NP231 do front digs? And a lot of other things it can't do. This is just an alternative to a Atlas.
 
You are missing the point. And we all spend tons of money needlessly on our rigs as it is.

Can a NP231 do front digs? And a lot of other things it can't do. This is just an alternative to a Atlas.
Yeah...I completely agree...but damn if they could just make a $1500 version...I don't need nuclear bomb proof...just artillery proof...

-Mac
 
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Yeah...I completely agree...but damn if they could just make a $1500 version...I don't need nuclear bomb proof...just artillery proof...

-Mac

They do. It's a DIY case and you add all the parts yourself. If you look long enough you can find a used D300 for under $300.