So I picked up another gearbox off eBay recently at a reasonable enough price and the buyer told me he had been running it in his R65 and it was going fine until he found another box and swapped this one out. It’s apparently been sitting for the last 5 years.
I’ve now fitted it up because I had a replacement (non leaky, low mileage) Final Drive to fit and I also needed to do a spline lube as well.
It turns out that the gearbox does have a problem...
The drive seems to just drop out? It’s only for a split second, but it definitely drops out. There’s no real noise to it or anything, a bit of a clunk maybe. I wasn’t actually sure that it wasn’t an electrical fault momentarily killing the ignition, but eliminated that possibility today and I managed to get it to virtually ‘slip’ as if the clutch were slipping fir about a half second. I’m pretty sure it’s in the gearbox.
My suspicion would be that the selector mechanism isn’t indexing properly, (it can be a bit clunky selecting and it’s got the odd false neutral) or that the selector forks are allowing the dogs to drop out momentarily for some reason.
I took it on a 50 klm run today and I noticed that it doesn’t misbehave while in 5th gear. I was thinking that it might have something to do with the shock absorber system on the input shaft, but the fact that it doesn’t do it in 5th makes me less suspicious of that.
I’ll just swap my old box back again soon, but I’m hoping that someone might be able to give me some indications of what’s going on. I guess it wants a full strip and inspection to get to the bottom of it but I’d be glad for anybody else’s input.
