Morris oils do a semi fluid grease. It's a 3kg tin and will probably last you a lifetime.
If your suck obtaining it, I can get it in for you as PES is a agent for Morris oils including industrial.
We use it in our gear shaping machines.
We have 3 WD G3l's in the family and all have their gearboxes lubed by Landrover one shot swivel housing grease. (I run a Landrover garage,so it is "free" to me...) The stuff I buy from them comes in sachets and is easy to squeeze into the filler cap. Google finds it easily, or you should be able to get it from any Landrover garage. It works very well.