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Installation Instructions for Installing the New Process 435 4 Speed Transmission into an Early Bronco

by Robert Sanders

Step 1: The first step is removal of the existing transmission and transfer case. While this can be accomplished without splitting them apart, it is not recommended. There is too much weight involved and the combined package is too awkward. 1. Remove both driveshafts and the speedometer cable from the transfer case. Also drain both the transmission and transfer case.

2. Remove all shift rods and mechanisms.

3. Support the transmission with a jack or adjustable jackstand and remove the crossmember.

4. IMPORTANT, put the transmission in 1st gear and fashion some means of holding it there. If you do not do this then the transfer case will drag the transmission output shaft backwards when the two units are split and the needle bearings between the transmission input and output shaft will drop out of place. The only way to my knowledge of putting them back in place is a complete disassembly of the transmission. If they do Fall out no biggie, just search around with a magnet or something to collect them all, then you Vaseline or something like that to stick them back in place. Obviously if you're going to trash your three speed anyway, this isn't too important to you, but the Bronco 3-Speed is worth a few bucks to a 4x4 wrecking yard so keep that in mind.

5. Unbolt the intermediate housing (the housing between the transmission and the transfer case) at the back of the transmission and using some form of transmission jack to support it slide the transfer case back until it clears the output shaft of the transmission.

6. Remove the jack carefully from under the transmission. If the motor mounts are healthy the transmission should drop only slightly. It may be necessary to unbolt the fan shroud to prevent the fan from hanging on it. The transmission can be unbolted and lifted back and out by a reasonably strong man, (it weighs approx. 75 lbs.) If you have any doubts however use the transmission jack. Step 1 covers removing the transmission and transfer case. Step 2 will cover cutting the hole in the floor. However, before moving to that it would only be natural to consider the clutch. If you have any doubts about it now is the time to change it.

Step 2: The next operation to be performed is cutting the necessary hole in the floor. I recommend using an air powered abrasive cutting tool. Experience has shown that such a tool does the quickest and easiest job possible. I have done the job however with an electric scroll saw equipped with a metal cutting blade. The scroll saw is a hand held saber saw that allows the head (blade) to be rotated 360 degrees. This is necessary because some of the cuts can only be accomplished by being able to pull the saw towards you rather that the conventional manner of pushing it away from you. If using the scroll saw you may still need either a cutting torch or an air powered chisel. A Sawzall may also work, though I have never actually used one. If you can come up with a method you like better than any of the above use it. 1. Remove whatever floor covering you have on your floor.

2. Use the line in the transmission tunnel where the floor changes from flat and slants up towards the firewall as your reference point for marking the hole that needs to be cut. The hole needs to extend up from that line approximately 4 inches and it needs to extend back from that line approximately 6.5 inches. It can exceed those measurements if desired, but must be at least those measurements. It needs to be approximately 8.75 inches wide centered on the transmission tunnel. (Some transmission kits come with a cover plate for the floor. If you have such a kit you can use that plate as a template. If using a cover plate as a template be sure to leave enough metal under the edges of the plate to enable you to screw it to the floor).

3. If using the scroll saw method, drill starter holes at the corners of where you plan to cut and any other place you deem necessary. Using whatever technique seems to work best for you and whichever method of cutting you have chose start cutting. ( Note: If using the scroll saw method plan on using more than one blade. It took me about 6 blades if I remember correctly. Usually when a blade breaks the first time, you can reinsert it in the saw and get a little more use out of it. The second time, however, it's too short to use). If you haven't realized it by now, you will shortly discover that there is a brace that runs under the floor that must be cut out also. I worried initially that removing this might weaken the structural integrity of the floor, but that does not seem to be the case.. After removing the section of the floor necessary, it will be necessary to further remove approximately 3 inches of that brace back under the floor on both the left and right side. If using the scroll saw method that is what the air chisel is for. It can be done with a torch but that will end up discoloring or warping the floor unnecessarily. If your using the abrasive cutting tool the brace can be cut back under the floor with that tool. That's another reason I prefer that method. Once the hole is completely cut take a break. The hardest part is done!

1. Lay your transfer case on its back with the 3 speed intermediate housing and input (spud) shaft sticking straight up. Unbolt the intermediate housing from the transfer case and lift it straight up and out of the transfer case. The input (spud) shaft will come with it. This is normal. If this was done correctly and carefully the needle bearings that the nose of the input shaft rides in will remain in place and will not cause any problems. If however they come out and drop into the bowels of the transfer case then the cover plate on the side will have to be removed in order to retrieve them.

2. Assuming no problems with the needle bearings, turn your attention now to the intermediate housing just removed. Remove the lockring holding the gear into the shaft and remove the gear. Remove the internal snapring holding the back of the of the housing and using a hammer handle or soft (brass) punch from the other end, tap the shaft and bearing out of the housing. Inspect the bearing, (which will probably be perfectly good), and if deemed serviceable, reverse the above procedure and install the input shaft, bearing and gear into the intermediate housing furnished with the 4 speed transmission.

Step 3: Now comes the installation.

1. Shift the transmission into neutral and remove the shift lever from the shift cover. Support the transmission on some form of transmission jack, (without the transfer case bolted to it), and install it onto your bellhousing. A useful idea before starting this is to obtain four 7/16 course thread bolts about 3 inches long. Cut the heads off and install the now headless bolts into the holes on the back of the bellhousing. These will now serve as temporary alignment pins during installation of the transmission. After the transmission is in these bolts can be removed with a pair of pliers and the permanent bolts furnished with the transmission installed. Check the transmission output shaft to make sure the transmission is still in neutral and if so, reinstall the shift lever. (Note: I have decided it's a whole lot easier to pour 3.5 quarts of oil down the shift tower with a goose neck funnel before reinstalling the shifter than trying to pump it in through the hole on the side of the transmission.)

2. Put the transfer case assembly on some form of transmission jack, lift it up and install it onto the back of the transmission. Take care that all four bolts going into the adapter plate are started correctly before trying to tighten them.

3. Once the transmission and transfer case are in place, the crossmember needs to be reinstalled. IMPORTANT: When reinstalling the crossmember reverse the relative positions of the rubber donuts that serve as the mounts between the crossmember and the intermediate housing. Put the thinner donuts on top of the crossmember and the thicker donuts on the bottom of the crossmember. Reinstall the bolts, sleeves, nuts and washers in their original positions. This is necessary to lower the top of the transmission slightly below the floor level of the transmission tunnel. Once this is done reinstall the transfer case shifter, the speedometer cable, the driveshafts and the clutch linkage (if removed.) Reinstall the exhaust system if that has been removed and you are finished under the bronco.

Step 5: The final operation is the installation of a cover plate fabricated to cover the hole in the floorboard. Secure a piece of sheet metal of adequate size and gage. Bend it to correspond to the angle in the floor. If you can get the use of a sheet metal break it will make the job easier, but it can also be done by clamping the metal between two 2x4's setting the line to be bent even with their edges. Once that is done, locate and cut the hole for the transmission tower. Do not make that hole any bigger than it needs to be, but make sure the tower does not rub on the cover plate. Attach it to the floor with sheet metal screws. You can then obtain a boot from Ford such as they use in their pickup trucks. You can also use a Hurst super boot or its' generic equivalent. With care and with a little thought the finished job will look like the factory planned it that way. I hope that I have given you enough information to get your 435 transmission installed and operating. I trust that once you do, you will be like me and wonder why in the world Ford didn't build it that way in the first place. With the possible exception of power steering, it is the single most significant modification I have made to my Bronco.









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