I checked the mechanical and electronic speedos for consistency in length / speedo gear width and teeth - both being the same only that the electronic speedo gear shaft is longer (longer as in a sitting inside the speedo sender, however depth of the speedo gear inside the box is the same on both). So both mechanical and electronic speedo senders (gears) should not cause any compatibility issues regardless of the inside ring colour.
I couldn’t find the blue ring to compare to the white however from memory different mounting as in can’t be swapped (couldn’t use my old non lsd early model speedo ring with lsd diff - had to buy the white).
Process of elimination, if you have tried, swapping the cluster, swapping the electronic speedo drive unit, tried spinning your speedo drive gear with a drill and output is consistent at a static speed, that would support the look into the gearbox.
But if guidance. Gearbox rebuild parts ordered last year, basics: seals, bearings, square bushing, drain bolts, selector boot (basics to rebuild / refresh, not including any synchros etc) with postage was $300+
post edited by TonyMR2 - 2019/02/05 09:49:52