3000 Transmission Removal and Replacement

By Roger Moment

Originally published in the Austin-Healey Magazine, December 1995


Someone recently posted a note on the Internet asking for step-by-step instructions on how to remove a transmission from their 3000. This article contains my reply, augmented with photos and additional bits that may be of particular interest to those having Concours cars and concerns about how to eliminate damage from the process.


First of all, take the gearbox out through the cockpit! Second it is best to use six-point sockets—they spread the load better over the bolt/nut faces and minimize or eliminate damage to the corners. You will need 9/ 16” for the hell housing bolts and 1/2” for the transmission mounts and overdrive harness clip bolt on the gearbox. Also, the series of accompanying photographs were taken during both removal and reinstallation. I did not wrap my gearbox with towels when I removed it, although I could have. It was repainted after working on the overdrive, so I wrapped it before installing. One photo of it unwrapped better shows how it is drawn into the driver’s side before sliding out the passenger side. Don’t worry about the inconsistency of how it is protected—the use of boards and towels to protect the interior is the same in both cases.


1) Remove both seats and floor carpet.


2) Removal of the transmission tunnel can be a problem because of interference from the gear lever and hand brake. I’ve found it easier to unscrew the gear lever knob and pull out the rubber shift boot (carefully so as not to tear it!). Then remove the gear lever (watch for the three nuts and lock washers and three spacer washers nested in the thick rubber pad under the cup. The tunnel housing must first be loosened so that it call be lifted slightly to provide proper clearance around the shift cup for removing the shift boot.


3) Lay a piece of 3/4-inch board that can span from the edge of the frame next to the transmission across to the side rail (passenger side). This is to give you something to rest the transmission on and protect the door facing on the threshold. Lay a doubled heavy towel over the aluminum finisher and fold rags to protect the draft seal and door panel from edges and corners of the hoard. Additional towels should be draped to protect the frame around the transmission and used to cover the underlayment. (Underlayment removal requires taking out the seat tracks which hold it down. I’ve found this isn’t really necessary if the relatively fragile material is covered with towels and the boards as described.)


Photo 1

4) Remove the rectangular fire wall panel that the transmission cover butts against (there should be three screws buried into the carpet along both vertical edges). Unplug the wiring harness from the 3rd—4th transmission switch and free it from clip on gearbox. Disconnect the speedometer cable and unscrew the right angle drive from the overdrive. (Removing this bit avoids the risk of damage should it hit something when the unit is being handled.)


5) Now jack up the car and set it on four stands to keep the car level. Set the height around 15 inches so that you can easily slide under the car and place pads of carpet to protect the frame from chipping.


6) Remove all the engine-transmission bolts that you can reach through the cockpit. The top right bolt screws into the block. There are two special bolts called dowel pins. These have a special shaft with a machined groove where the threads begin. The head is flat (no circular dimple) and may have machining marks visible. Leave the two bolts at the bottom of the bell housing in place for now. Nuts on the top left and middle left bolts are most easily reached from underneath. Set an open-end wrench on them which will jam against the foot well as you undo the bolt from the cockpit.


7) Remove the bolts holding the clutch slave cylinder the bell housing, cotter pin and clevis pin. The push rod can be left in the slave cylinder. Check the clevis pin for wear!


8) Disconnect the cable from the starter and remove the two starter bolts. Place heavy towels over the frame and a rag between the starter and engine to protect against chipping any paint. The starter can be removed from underneath by sliding it forward and over the right frame rail.


Photo 2

9) Disconnect the drive shaft and push it back towards the differential. Some grease will squirt out of the yoke. Use paper towels under the yoke to catch the grease and protect the frame paint.


10) Place a hydraulic piston jack under the engine pan. Use a 3/4” board against the pan (with carpet or towel pad) and a steel plate 1/4” thick and 3-4” square to spread the load from the jack punch point to the board. Pump the jack until the boards just rest against the pan bottom and the engine is supported slightly. (Photo 1)


11) Undo the rear transmission mounts from the frame and the drag link to the frame crossmember. (Photo 2)


12) Wrap the transmission with a large towel. Leave some bunched material at the rear for drawing over the rear mounts when they are free of the frame.


Photo 3

13) Place a floor jack with the pad built up about three to four inches using wood blocks under the cast iron transmission housing. Leave about three to four inches of level gearbox housing clearance between the jack pan and bell housing so that it can be slid rear-wards without interference. The blocks will fit up between the main frame rails when the jack is raised and will prevent interference from the jack arm hitting the frame. Cover the blocks with a pad of carpet and jack up until contact is made. Then jack up the transmission about 1/2” so that the rear mounts clear the frame and raise the jack under the engine so that it “keeps up.” The top flange of the bell housing must clear the fire wall/scuttle when the transmission is drawn back into the passenger compartment. Draw the bunched towel out to cover the transmission mounts, wrap it and hold it tight with spring clamps.


14) Place a second board on the driver’s side floor. Stand in the passenger compartment with one foot on either side of the drive tunnel. Grab the transmission by the rear mounts and draw it back, using the wood on the floor jack under the housing as a resting surface. (Photo 3.) You will need to stabilize everything from rolling too far left or right, but you should not have to support much weight on your own, yet. As the bell housing parts about two inches from the engine, drape a towel over the top edge. Work the overdrive over to the driver’s side and carefully slide the bell housing flange past the scuttle panel opening. There is relatively little clearance. This operation should leave the overdrive over the driver’s floor and the gearbox/bell housing resting on the jack pad.


Photo 4

15) Stand in the cockpit, grab the top front of bell housing and rear drive flange, lift and slide the transmission to the passenger side and rest it on the large board. Slide towards passenger door, and reposition yourself to lift it out of car. Watch out for hand brake handle.(Photo 4 & 5)


16) Installation is the reverse, except use the transmission jack to control its height until you think it is a good match to the engine. The gap between bell housing and rear engine plate must be close to perfectly uniform left to right and top to bottom in order for the spline and pilot to line up. Use the jacks and pivoting motion on the wood jack block to make fine adjustments. When you think things are right, push it home. You need the transmission to be in gear so that you can rotate the input splines by turning the output shaft. Fourth gear is the best choice for this. Insert bolts through the cockpit first to line up the holes and then go underneath and insert the bottom two. Tighten these snug before putting nuts on the upper ones. Once the bottom two bolts are fixed you can remove the jack from under the engine pan and lower the transmission and engine into place using the floor jack under the gearbox. Stop when the rear mounts are just free of the frame so that they can be pushed laterally for lining up the mounting bolts.


Photo 5

17) Install all the other bits in reverse order from their removal. I use a 1/4 to 1/6 diluted solution of Simple Green, followed with a Windex rinse, to wash down the frame, wiring harness, brake and fuel lines, and anything else within reach.


18) The transmission tunnel should be set loosely in place before the gear shift lever is installed into the gearbox. It is appropriate to firmly attach the scuttle panel using its six screws before installing the tunnel.


19) Once the tunnel is located, install the gear shift lever. Use some lubrication grease on the ball and pocket of the bronze bushing as well as its outer surface. Line it up with the lever axis and use a screwdriver to position the cup in the shifter hole with its pocket vertically. Carefully insert the lever, with bushing attached, down into the case. If it doesn’t go in perfectly smoothly, pull it out, realign the bits, and try again. When done correctly it will slip right into place. DO NOT FORCE ANYTHING!


20) Now install the hardware that holds the lever in place. I found it works best to first slip the three cylindrical collars over each of the studs. Then feed the thin gasket, molded plate, thick rubber spacer and finally the top retaining cup over the lever and drop them gently onto the three collars. If done properly the thin gasket will not work itself loose under any of the collars. Carefully set two of the lock washers and nuts over the two studs that you can most easily have access to and tighten them down firmly. Shift the transmission to gain access to the third stud and do the same. Tighten all nuts until solid resistance is felt, but don’t overdo it.


21) Fitting the rubber gaiter is most easily done as follows. Slide the boot over the shift lever with the cylindrical cup/sleeve side down and the accordion folds and grooved lip (that will fit over the edge of the tunnel opening) up. Lift the tunnel cover about one to two inches and work the entire gaiter through the hole. Using feel, slip the cylindrical sleeve over the metal cup cover for the gear lever retaining assembly. You can feel through the thin rubber membrane for the metal cup edge to be sure that the gaiter is over it. Then reach down through the tunnel hole and grab the top lip of the gaiter, pulling it carefully through the hole and setting it around the edge of the opening. Start at the 9:00-10:00 position (where the cup and cover are closest when everything is in place). While you perform this task the tunnel will concurrently be slowly lowered into place.


22) Use a small punch to align holes for the eight floor and two scuttle panel screws to secure the tunnel. I find installing the scuttle panel screws first works best. Use the punch to locate one set of holes and press against the tunnel to keep it from sliding out of position while you insert each screw. Don’t over-tighten. The sheet metal is easily stripped out. Go to #8 screws if the original #6 size has no bite, but use the original holes.


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