Reinstall the diff oil drain plug and torque to specifications 29-39 ft-lbs. Trying to pass a slow vehicle uphill is almost impossible. If not you'll probably have to tear the entire unit down. Some bearing houses will not sell retail to an individual, but my 2nd phone call to a store listed in a Business to Business directory, found someone within 15 miles of my home. Use plastic bags, sealed, and marked with indelible ink.
Note that it has pipe threads, so there is no sealing washer required. Whatever you use needs to have a long, relatively slender tip or hose to get down into the recesses of the turret and reach all the old oil. I purchased a thin chisel then set about grinding it to fit into the key slot. The old torn lower shifter boot is at top left, having been removed from the shift lever, bottom. Step 8: Looking down into the shifter turret, you can see the rectangular boss with circular cutout into which the shifter engages, the shifter locating pin at the top, and the dirty, filthy old shifter turret oil. Rods' manual made it seem like the input shaft slides pretty easily through the bell housing bearing and only taps with a plastic or rubber mallet are needed to mate the cases. You'll need some nuts, bolts, and washers too but look at the manual and it will be clear what you'll need.
Keep sub-assemblies together in big, re-sealable plastic bags or on wooden dowels and mark the bag with an indelible pen where the parts came from. Check for proper shifting action. You are supposed to have between 0 - 0. If you did not remove the upper boot in the previous step, the view will be similar except the upper boot will be pulled up over the shifter lever. If your tranny is 'bad' or needs repair you can probably get a low mileage tranny from a salvage yard pronto. Make sure the bell housing bearing is completely seated.
So as you assemble, you'll measure and then have to run to the dealer to get the correct sized component, unless you are incredibly lucky and all the clearances match up. If torn, the boot should ideally be replaced as it isolates the passenger compartment from both heat and noise. Once the tranny bell housing, mid-carrier, mid-section, and tail shaft are together basically the tranny is assembled except for installing the input shaft snout , you need to test the tranny. Not mentioned was the step that you need to temporarily install the input shaft 'snout' someone told me it's called it a 'quill'. I've written this for two reasons.
For the adventurous and determined! Make sure the tranny spins freely not having the snout installed allows you grab the input shaft and easily give it a twist So twist it. The correct differential oil fill level is just up to the bottom of the fill plug hole. Please do not assume anything else will be included if it is not pictured. Good luck and many happy Miata miles! Note: this is one tool you can purchase but it's a Mazda specific tool. This sits in the front of the tranny and prevents the input shaft bearing from backing out of the bell housing as you lower the gear train into it and then have to pound away to push the input shaft and gear train into the bell housing. Clean up, put your tools away and go out for a top-down test drive! So while it isn't the most difficult job you should be an accomplished shade tree mechanic. Mazda parts numbers won't help a bearing supply house.
You can spend lots of frustrating time trying to slide snap rings off with screwdrivers, or use the correct tool and be done in 5 seconds. Sell the car at a fair price to someone, letting them know the tranny needs work, and buy a new Miata! We do our best to prevent these issues from happening and apologize for any inconvenience it may cause. This vehicle is unsafe to drive other than on flat, low speed, city roads. I broke two larger ones and good ones too! Check the oil level of the transmission and differential at least as frequently as specified in your Miata Owners Manual and top-up as necessary. You need to be creative.
The mechanic doing the job only has to walk to the parts counter a few times, you'll have to haul out, part in hand to get a replacement. The input shaft pokes through into the bell housing area, through the front snout of the tranny on which the throw out bearing rides. Maybe your manly screwdrivers are better than mine. The back end of the 'spoon' fit at the base of the key slot and acted as a leverage point and the upper edge pushed the flange metal up as I cranked down. You may verify with your local dealer if a re-learn is required for your vehicle.
I couldn't quite free the flange all the way so I took one of the broken screwdrivers and made a spoon shape out of it. You'll save tons of time if you can pry those flanges up quickly. I tried also sort of things like using shorter bolts and sections of chain to the hub puller, etc. Unless you are extremely lucky you can count on your Miata being down for 2-3 weeks. Step 4: Once the transmission oil has fully drained, replace the drain plug with a new or reused sealing washer, and torque the plug to specifications 29-43 ft-lbs. The vehicle is in the local Mazda dealer's service department where they have not found the cause of the problem. If it happens, well once again you've got options, like going to a salvage yard or having someone else repair it, but don't be too hard on yourself, I've talked to a few professional Mazda mechanics and it happens to them too.