fc na, questions about my gearbox,diff and halfshafts,pics included.
 

Hi Folks,
i have an fc n/a 6 port and i need some help identifying my gearbox and diff as i think they are not standard.

i looked in the fsm for the transmission and it shows the smooth case transmission with integral bell housing for the n/a model but my car has what looks like a turbo transmission.

it has the ribbed case, inspection plate on the bottom and a separate bell housing with small inspection plate on the bottom of that.

the first 3 are the best pics i could get of the gearbox from underneath.

the next 2 are various angles of the diff and 1 of the tail shaft rear joint at the front yoke of the diff.

the tail shaft measures 57mm diameter, like the standard n/a manual tail shaft diameter from the fsm and the half shafts measure 24mm diameter.
sorry i dont know the imperial measurement.

i have searched the forums for the half shaft diameters with no luck but i have found that they are different between the n/a and turbo ones but i havent found the actual diameters anywhere.
i also checked the faq section.

on the drivers side (im in sydney australia so your passenger side) on the side at the front of the diff there is raised lettering that looks like SSOW.

it looks like to me that i have a turbo gearbox but with a n/a tailshaft and i have no idea what diff.
as you can see in the pic my drivers side stub shaft seal is leaking,and i havent driven the car yet so its leaking just sitting there.(i have had the car just over a year and i am nearly finished building it.)

the reason i need help identifying the gearbox and diff is because the rear seal on the gearbox where the tail shaft goes is leaking as is the stub shaft seal on the diff and i need to know what i have so i can order the right seals from mazdatrix.

i have noticed on this page form the mazdatrix website,
http://www.mazdatrix.com/G8DiffMnt.HTM
in the pic showing stub shafts that the 27-270A-P016 (marked 87 lsd) shaft has the same lip between the flange and axle that mine has.
the other stub shafts dont have this lip.
you can see on the pic where the red line goes across the 2 stub shafts, the first one has a lip and the second doesnt.

i havent pulled out the stub shaft yet so i cant measure if its the same as in the pic but in the next few days i will.

when i turn the drivers wheel clockwise the other wheel doesnt really move for about one and a half full turns then it starts turning counter clockwise a bit at a time so i dont think it is a lsd.

i dont have too much confidence in the diff center being any good because of this as it doesnt turn smoothly and in sync with the opposite wheel but i havent driven the car to know if it is any good.

thats about all the info i can think of at the moment.

any help in identifying these items would be greatly appreciated.
i hope the members here can help me as im stumped as to what the diff is.
Thanks,
David.

quick update.
i have found out that the n/a half shafts are 24mm (like mine) and the turbo is 26mm.

also, i have the car up on stands with the wheels off so i started it up and ran it through the gears and it drives both rear wheels so im hoping this is a good thing.

again any help would be greatly appreciated.

Thanks,
David.

That's a TII transmission (R type) or possibly RX-4, I can't tell from the pictures.

Hard to tell on the diff without a frame of reference in the pictures. However that appears to be an NA diff. The TII unit is much larger as seen in the picture below:

http://www.aaroncake.net/rx-7/projec...sition%201.jpg

Thanks
 

Hello Aaron Cake,

Thank You for the reply and the pic.

yes the 2 diffs are different,the one in your pic has more cooling fins and has different features.
i will order a stub shaft seal for an n/a diff but also order one for a turbo diff just in case as they are pretty cheap.

regarding the gearbox, i didnt know that there was an rx4 5 speed gearbox, never seen one here in australia but i think i remember that they may have been available in japan.

i thought maybe it was an rx5 5 speed but i have seen pics of one and its different, there are more ribs on my gearbox.

mine also has the rx7 short shifter, see attached pics.

the shifter on mine is really sloppy and missing the top bushing and spring so i will order both the top and bottom bushing kit from mazdatrix.

regarding the tail shaft, mine measures 57mm diameter like an n/a tail shaft but from what i have read these dont fit in a turbo gearbox, apparently you need a turbo tail shaft as the output shaft splines are different.

i also read that when the uni joints go on a standard tail shaft the whole shaft must be replaced but my shaft has circlips on the uni joints and a sticker that says something about servicing at a certain time, maybe my tail shaft is a non standard custom tail shaft.

i can only see the very back of it as in the pic as its covered by the exhaust system.

Thanks again for the reply and pic,
Much Appreciated,
David.