DIY 68RFE Build

Couple tranny guys have told me it’s not a good idea to start my transmission building career on the 68 (too technical I guess), so I figured I’m gonna try it (700 hp).

I got the book and lots of YouTube videos with a nice shop and building a table to try this.

Parts acquired:
Transmission core (with internals)
Sonnax underdrive kit
Cherry bomb (billet input shaft with all drives)
Complete alto clutches and plate kit (700 hp)
Low stall triple disc torque converter
Billet flex plate
Deep pan

Parts needed:
Valve body
Pump
Solenoid pack
Filters and oil
Possibly a new cover if current one junk?

I’m way out of my league here and still willing to listen to reason but also determined cause I got time.

I would like to here input on valve body pros and cons on different manufacturers.

I tow all the time and my intention is to have 600hp after the tranny is good for it.

My overall point in this is to still have my stock tranny (still working fine) and not have to give it for a core so down time will be minimal and I just really want the challenge!

Any input or questions welcome.

Thanks.


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Quote:

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Originally Posted by BLACKDIAMOND

Couple tranny guys have told me it’s not a good idea to start my transmission building career on the 68 (too technical I guess), so I figured I’m gonna try it (700 hp).

I got the book and lots of YouTube videos with a nice shop and building a table to try this.

Parts acquired:
Transmission core (with internals)
Sonnax underdrive kit
Cherry bomb (billet input shaft with all drives)
Complete alto clutches and plate kit (700 hp)
Low stall triple disc torque converter
Billet flex plate
Deep pan

Parts needed:
Valve body
Pump
Solenoid pack
Filters and oil
Possibly a new cover if current one junk?

I’m way out of my league here and still willing to listen to reason but also determined cause I got time.

I would like to here input on valve body pros and cons on different manufacturers.

I tow all the time and my intention is to have 600hp after the tranny is good for it.

My overall point in this is to still have my stock tranny (still working fine) and not have to give it for a core so down time will be minimal and I just really want the challenge!

Any input or questions welcome.

Thanks.


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68RFE is easy.

700hp is where it gets tricky as everything becomes the weak link.

Who's parts do you currently have for each of these things as they are not all created equal.

Probably want to ditch the sonnex drum as it's just not going to handle the necessary line pressure.

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The Sonnax is billet and has the same part number as as 700 hp trannys I'v found, but I can acquire different on that if needed.

I have a Suncoast flex plate and converter.

Not sure on the brand of cherry bomb but it was marketed as 700 hp.

The alto stuff was all marked 700 hp from the alto factory so I would imagine that’s good?

Ya the so the billet input shaft and the assembly could be questionable?


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The issue isn't the billet with the sonnex drum it's the bolt on plate.

They have a tendency to fail beyond 200 psi.

It literally just shears the screw heads right off.

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What should I be looking at to replace it?


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Quote:

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Originally Posted by BLACKDIAMOND

What should I be looking at to replace it?


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Hopefully some guys with experience with their own dd 700hp trucks will chime in here.

I'd be looking towards revmax or suncoast for a more stout drum if I was building it for myself.

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Quote:

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Originally Posted by badbajawa

The issue isn't the billet with the sonnex drum it's the bolt on plate.

They have a tendency to fail beyond 200 psi.

It literally just shears the screw heads right off.

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Sonnax just released an updated drum with a different bolt on plate and different bolts.

I use different bolts I bought a box from grainger haven’t had the bolts break since.


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Quote:

---

Originally Posted by BLACKDIAMOND

The Sonnax is billet and has the same part number as as 700 hp trannys I'v found, but I can acquire different on that if needed.

I have a Suncoast flex plate and converter.

Not sure on the brand of cherry bomb but it was marketed as 700 hp.

The alto stuff was all marked 700 hp from the alto factory so I would imagine that’s good?

Ya the so the billet input shaft and the assembly could be questionable?


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I don’t like Sonnax drum above 650.

I haven’t tried the new revmax inner drum with sonnax outer yet though. It’s supposed to take some big power though.

Stay away from NexGen.

Stay away from GPZ clutches they compress seen some lose .020 in less than 20k miles.

For 700 I’d use Revmax 850 drum, billet input, billet Revmax center support.

Upgraded sprag, upgraded pump and valve body both with billet plates, factory borg clutch’s in input drum and low reverse, alto g3 in 2c and 4c.

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