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Discussion Starter #1
I have an Early Bronco with a fresh 393W. I currently run a NP435 granny 4spd, but have a C4 that I'm wanting to build and swap in. The C4 is an early Bronco model out of my 77 parts rig. I want to build a stout tranny that can live at low speeds on the trail and take 400 ft/lbs of torque. What mods are recommended?
 

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Usually Bronces are heavier than cars and use bigger tires. Along with being 4x4 that adds load to the trans. The Bronco C4 is a good trans. Usually they already have "H" or "R" servos. I would recommend you add a clutch to the direct drum and keep the clearence to a minimum. Use a GOOD valve body to keep the pressure up along with a good cooler.
 

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Discussion Starter #4
I finished pulling it apart this evening. I found a hardened 26/24 spline shaft, "H" servo, 5 foward clutches, and a wasted set of high/reverse clutches. Wasted to the point that there was no friction material on any of the clutches and the piston had overtraveled and wedged itself sideways. Talk about a pain in the butt to get the spring retainer off and piston out.

I'm thinking of using Alto clutches. I plan on adding one disk to the high/rev and may add an extra to the foward. Should I swap both bands to Kevlar or just the intermediate? I also plan on using the BURLY4X4.com valve body mods, drilling the high/rev drum, and removing the check balls from the stator. Any other suggestions?

I think I should have a pretty stout little tranny when I'm finished.
 

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That goes to show you that the direct drum needs help. It's always the first to go.

I really don't have a strong opinion on running Kevlar band on the rev drum. I have never had one fail. One good thing is kevlar bands are as cheap as conventional bands, so for the cost, why not.
 

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Discussion Starter #6
I ran a Kevlar on the rev in the last tranny I built with a brake. But as you said cheap insurance.
 
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