My JL gearbox shows a (tiny) bit of play on the front ball bearing of the constant pinion shaft and therefore I would like to replace this bearing C.1838 and at the same time replace the needle bearing C.1843 at the other end as well. The rest of the box looks (very) good including the synchro’s and main shaft bearing (no play at all).
The manual describes the total dismantling of the gearbox during which the countershaft is removed and the gears drop on the bottom of the box. The constant pinion shaft has two cut-away sections in the fourth gearwheel to pass the gears of the countershaft.
Is this only possible with the gears of the countershaft on the bottom of the box or could it pass with the countershaft + gears still in position?
I wish I knew. I had my JL apart about a year ago and I’m sure I picked up the counter gear after the shafts but I couldn’t tell you if you really do need to drop it. To leave it alone would certainly lower the annoyance level. My gut tells me it won’t clear unless you do.
I’m sorry to be the bearer of bad news, but no it will not pass the front countershaft gear in place. The cutouts are there so it will just pass with the countershaft dropped down.
The good news is you can make a dummy countershaft to slide in there and let it drop without losing your needle bearings. I did it last winter on my SS double helical gearbox and I think I recorded the length and diameter of the dummy on the pre-xk forum. But it might be a different length, I’ll look for it.
You’re learning Rob: long live the decimal system! (Apologies: I know, no politics on this forum!!!)
But also thanks for the bad news and the dimensions of the required dummy shaft.
Found another reference in one of the Haynes Workshop Manuals that refers to .979" OD but I assume the ID of all these needle bearings on the counter shaft, were based on 25.0 mm nominal shaft diameter. So the 192 mm long dummy shaft has a diameter of 24.8 to 24.9 mm.
