Gary- I might add that I have not seen "wear" on the syncros on any of the
Moss/Jag boxes that I have rebuilt. I am sure it does happen- just haven't
seen it. What does seem to happen is that the springs in the sycchro hub
fatigue with age & probably heat... mostly age I Imagine. This reduces the
pressure between the synchro cones and lets you engage the gears (hubs)
before the other is up to speed- & it grunches. The synchro faces seem to be
protected by the film of oil between them & I've done boxes run on 90wt &
30wt & don't see "wear" on the actual synchro surface.
What does happen is that when you shift too quickly before the cones do their
job to bring the hubs "in sync" .. the teeth in the hubs grind together to
bring the hubs to the same speed, That's the "grunch"...
The thicker 90wt might help the cones a bit in bringing the hub to speed.
Still it is a slow shifting box, even the best are...
I've run both 90 & 30 in the Moss box... 90 is probably a scosh quieter. I
went back to 30 & probably would run Redline MTL now.
But... with the overdrive- As I told you- I would recommend 30wt- no
synthetic. Synthetic is too slippery- bands could slip- 90 might be too heavy
for the valving.
Fred Sisson
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