Upgrade Projects

Early Bronco

Late Model






Converting to a
C4 Transmission

To use a C-4 or C-5 out of a car or truck other than the Bronco you have to use the Bronco tail shaft which means taking apart the tranny to swap them. It is far easier to use a complete C-4, flex plate, convertor, t-case input shaft, all misc. bolts, intermediate housing, and auto starter straight from an EB! Since this is often a source of confusion, it is repeated below:

The Early Bronco had some transmission parts that were specific to this vehicle. You must use the correct part for a proper conversion.

You'll need:

C-4 or C-5 transmission and bell housing
Bronco flex plate and bolts
Automatic transnsmission starter (available at any parts house)
Early Bronco Intermediate Housing; the housing that goes between the trans and the transfer case. This is one of the hard to get and expensive parts. It only came on a bronco. Now the only new ones come from Advance Adapters, and they're very proud of their stuff.
Intermediate Shaft; the shaft that goes between the trans and transfer case. Another expensive bronco only part. Currently produced only by Advance Adapters. You may also have the existing shaft shortened.
Shifter; see above.
Transmission cooler or a radiator with the transmission cooler inside.
Transmission cooler lines
Automatic shifter

The steps for the conversion are:

  1. Follow manual directions for removing t-case and tranny. Make sure and insert the special tool for the manual tranny when seperating the 3-speed from the intermediate housing. Remove the fly wheel and dust cover. Note that you can make this tool by bending a piece of all thread and putting a couple of washers and nuts on it. (Thanks to Leland Wilson for this tip and much of the technical consulting that went into this article).
  2. Remove the bolts holding the t-case and intermediate housing together with the t-case sitting vertical, input shaft pointing straight up to keep the t-case bearings from dropping into the t-case.
  3. Remove the intermediate housing.
  4. Remove the input shaft to the t-case if it didn't come out with the intermediate housing. Note: the manual intermediate housing has a bearing retainer lip built into it, unlike the intermediate housing for the auto.
  5. Remove the C-clip holding the input gears to the input shaft. (It's not as easy as it looks!)
  6. Install the input gears onto the t-case input shaft from an auto.
  7. Install the input shaft into the bearing retainer.
  8. Install seal into bearing retainer. Put o-ring on bearing retainer and install intermediate housing to t-case.

NOTE: You'll need to have the t-case linkage bolt hole drilled larger if you have a T-shift t-case and want to keep it.

You can either install the auto and t-case together or seperately. The rest is just a matter of hooking up the cooler lines, cooler, shifter, etc.

Also see:

General Early Bronco Transmission Information
Off Road Torque Converters

Email us at:
Many thanks to our Contributors.
© 1996 - 2019