NV3550 Transmission – 5 Speed for Early Bronco

Preparing the NV3550 transmission for the bellhousing adapter

Match the bellhousing adapter to the front of the NV3550. Mark the transmission where the top two holes of the adapter meet the front flange. A small notch will need to be ground into the flange to provide clearance for the bolts. Carefully use an angle or die grinder to grind the clearance for the bolts. NOTE: The NV3550 transmission has an aluminum case. This material grinds very easily.

Bellhousing adapter plate installation

Install the bellhousing adapter plate to the NV3550 using (9) Allen bolts supplied.

NOTE: Use Loctite.

Removing the original transmission

Remove the driveshafts, shifter cables, and exhaust (if necessary).
Remove the original transmission and transfer case assembly from the vehicle. Leave the bellhousing in the vehicle.

Transfer case adapter to Dana 20

Remove the transfer case adapter and stub shaft from the original transmission. Apply the new AA gasket to the transfer case. Aligning the transfer case adapter with the most clockwise holes will match to the factory indexing (lowest setting). You can use the other set of holes for a higher rotation; however, this can cause some problems with body clearance, frame clearance, and transfer case shifter linkage alignment. The higher rotation does give you better ground clearance and is a nicer fit onto the new crossmember mount provided. Once you have chosen the rotation, use Loctite and install the (6) Allen bolts.

Installing the adapter and transfer case assembly to the NV3550

Grease the NV3550 tail shaft splines and install the stub shaft & bearing assembly. Apply light grease to the o-ring and attach the transfer case to the transmission with (6) bolts using Loctite. Use the driver’s side top 2 bolts to attach the transfer case shifter bracket.

Prepare the body for the shifter hole

Measure the NV3550 (with the front adapter plate installed) from the edge to the shift tower. It is best to make a template. Measure the location on the body to be cut for the new shifter.

NOTE: To find your measurement, it is best to do this with the bellhousing still installed.

Removing the bellhousing and clutch assembly

NOTE: It is recommended that the flywheel be turned and new throw-out bearing be installed with the new clutch disk.

Checking flywheel pilot shaft hole depth

The NV3550 has a slightly longer pilot shaft than the factory 3-speed. The factory Ford flywheel should have enough depth to accommodate this; however, if it does not, up to 1/4” may have to be trimmed off the end of the shaft. A simple angle grinder with a cutoff wheel is suitable.

Modifying the factory bellhousing to match the NV3550 transmission

Match the bellhousing to the transmission to measure the clearance.

1. Drill holes at the bottom of the existing vent hole to widen it.

2. Use a die grinder to smooth out the hole shape.

3. The final shape should be large enough to clear the front shift rail of the NV3550 transmission. This relief should not be cut down into the bellhousing index diameter.

Match the bellhousing again to the transmission to confirm clearance when bolted together.

Installing the new clutch and bellhousing assembly

Use Loctite on the flywheel bolts if they were removed. Remove the original pilot bushing from the flywheel and install the new AA pilot bushing (do not grease pilot bushing).

Install the bellhousing and clutch assembly, tightening all bolts to the specified torque. Install the NV3550 transmission, being sure to match the bolt pattern and verify the input shaft is properly seated.

Reinstalling driveshafts and transmission crossmember

Install the driveshafts, transmission crossmember, and torque the transmission mount.