Since I was unable to find any information on this proceedure other than the TSB, I figured it could use a short write-up.
Note that I will be glossing over 2 minor steps in this write-up... Getting the Transfer case out and back in again! I did this while the car was apart having the clutch replaced.
STEP 1:
Obtain the services of a nice man with a hoist to remove the transfer case from the vehicle. I used Chris at Intech Motorsport in Werribee.
You should now have an item that looks something like Photo 1. Your mechanic of choice may or may not remove the cooling unit (this does not beed to come out) or the joint shaft.
The joint shaft is the shaft to the right of the transfer case in Photo 1. This carries power from the front diff to the Driver's side driveshaft, and goes right through the middle of the transfer case input shaft. If still attached, undo the 5 bolts holding it onto the side of the transfer case with a 12 mm socket and carefully pull it out. Very little force should be required but there is a seal in there that you need to be careful of.
Photo 2 clearly shows where mine is leaking... across the top.
STEP 2:
Again using a 12mm socket undo the bolts on either side of the joint. There is 7 bolts on the front (engine side) 5 across the top and 2 long ones towards the bottom. There is another 6 on the back (tailshaft side). All of the bolts are the same except for the 2 long ones on the front.
Once you have pulled out all of these bolts the only things holding the case halves together are sealant and 2 dowel pins. Mazda graciously provided crowbar points at each corner of the case for prying it apart. Using a couple of large screwdrivers or other suitable prybars gently separate the 2 halves, going a little at a time on each side to pull it off the dowels as straight as possible. I used several thin pieces of MDF to slip into the gap to stop it closing on one side while I crowbarred the other side of the case.
If you have it upright, once you crack the seal any remaining oil is goping to exit the case...
You should now have something that looks like Photo 3.
STEP 3:
Thoroughly clean both mating surfaces. My case had 2 distinct lots of sealer on it, showing that A) This had been done before B) They didn't clean the old sealant off properly last time.
The TSB calls for cleaning the surface with Brake Cleaner... I used acetone to clean all traces of the old sealant off, then brake cleaner for a final wipe down. Beware of lumps of sealer falling into the case!
Also in the "sump" part of the case is the pickup for the oil pump... this just pulls out to get it out of the way for cleaning the faces, just don't forget to put it back!!!
STEP 4:
The one useful piece of information I was able to find regarding this job...
The TSB calls for "Permatex Ultra Grey RTV", apply it to one half of the case as shown in the TSB and carefully slide the other side back onto the dowels.
STEP 5:
Insert all bolts and spin them up to contact by hand. Once you have them all in you can start doing them up. I did them up in several stages, going round in a fairly random pattern. I Could not find a torque setting for them so I used the seting for holding the gearbox cases together, bellhousing etc of 37.3-52 N-m {3.8-5.3 kgf.m, 28-38 ft-lbf}. I went a little above the minimum spec.
STEP 6:
Ideally there should be a nice bead of sealant ozzed out all the way around the joint. Clean this up with some rags.
If possible leave the sealant to fully cure (24 hours in normal conditions) before refilling the transfer case with oil, or otherwise exposing the sealant to oil/grease/solvents.
STEP 7:
If you removed it, reinstall the joint shaft and bolt it back in place.
STEP 8:
Obtain the services of a nice man with a hoist to install the transfer case into the vehicle... Chances are your car is still stuck on the same hoist it was on when the case came out... I will be using Chris at Intech Motorsport in Werribee when mine goes back in tomorrow(ish).
STEP 9:
Enjoy the lack of burnt oil smell through the vents whenever you pull to a stop with the heater/AC on external air...
A note of caution. The input shaft, which is in the "front" side casing, is only a sliding fit. It will pull out quite easily, and I do not know if this may cause bad things(tm) to happen. It should not slide out under it's own weight, but will slide out if you try to lift the case half by it....
A note on tools... You will notice a rattlegun on the bench in one of the photos... This was only used for disassembly. I used a small ratchet and a torque wrench to put it back together. If you attempt to put your case back together with a rattlegun, good luck to you...
Hopefully this will help someone.
Cheers,
Chris.