Some information on MX5 gearboxes
The gearbox that Morgan use is from the 5 speed Mk3 MX5.
There have been virtually no issues with the 5 speed unit made by Mazda for the Mk3 when fitted in MX5's. 2005 to 2015.
I believe the UK supplier of these boxes to Morgan do indeed modify them for use in Morgans, therefore checking out the MX5 forums may or may not be that much use depending on what the supplier has changed on the transmission.
There were gear change issues usually when cold with the 6 speed box in the MK3 that was made by Asian which were usually solved by replacing the gearbox oil with Redline MT90 or Castrol Syntrans Multivehicle, this box had a selector chamber with oil in it and some owners have replaced a plastic collar and changed oil with some good results and others with no improvement. 2005 2015. This box is not used by Morgan.
There are issues in the MK1 and MK2 5 speed box selector and the gear change was improved by replacing a selector chamber boot and a plastic collar and while you are in the selector gubbins the oil is changed. 1989 to 2005. Again not used by Morgan.
There were also issues with the Asian manufactured 6 speed box installed in certain high spec MK2 and Mk2.5 cars, these did not have any oil held in the selector chamber as it was open to the gearbox. The main fix there was to replace the gearbox oil with either Redline MT90, Castrol Syntrans Multivehicle or a Ford gear oil that I do not have the details of. 1989 to 2005. Again not used by Morgan.
The gearbox on the MK4 or ND has had quite a few issues and is now on to revision 4. Mazda have had to change a number of the boxes in the UK. Europe and the US. Again not used by Morgan.2015 to present.
