15k mile prop-shaft lube overkill?

I think your analysis of the situation is pretty good, esp. regarding driving in water. You should be OK extending the intervals unless you go offroad frequently.

I feel more comfortable greasing the ujoints on a regular basis because it doesn't hurt to do so. The driveshaft slipjoints OTOH don't need as much attention. If you could get the special lithium grease that is typically spec'd for slipjoint splines, you could pull off one end and clean and grease the splines very infrequently. Like you said, you don't want the shaft binding from hydraulic lock, but at the same time you don't want it binding from rust or chattering from spline brinneling.

Toyota MDT in MO

I go offroad or am in 4WD about 50 miles a year and usually not in mud. Is water or dust the main reason there? I also haven't lubed the front shaft much at all, since it's not moving most of the time. Would the grease deteriorate just sitting still?

Truth be known, part of why I don't like doing it is that I am jinxed with mini grease-guns being a bitch to refill. I can never get the old tube out, so I end up scooping grease from a new tube into the previous one. I find regular grease guns too big to maneuver well under the truck.

Waters

The little guns can be a pain, and they don't provide the pressure either. Forgive me for asking, but could you be putting the carts in backwards? The smooth end without the metal ring goes facing into the gun. The ring end is toward the front and can easily be grabbed with a plier if needed.

I would hate to admit it if that's so, but whatever way I've done it always seemed to be the only way it would work. I'll have to double check that. It seems like they develop extreme suction when I try to replace them, even if I take both ends off the gun.

Waters

Waters schrieb:

I'd like to add that when you over-grease the shaft you will build up a solid 'block' inside. That is, because fluids don't compress. Compression occurrs when you load the vehicle or the suspension is moving. This may cause the diff and/or the tranny to be hevaily stressed up to failure.

You may gently fill the reservoir of the shaft (not much pressure, you easily can build up several tons like an hydraulic cy

hole!)

Are you saying the front-to-back sliding part of the shaft may contain overcompressed grease, even if it always seems to return to its initial position after "expanding?" I had done that for 260k on a previous Toyota 4WD truck and always thought the grease found its way out along the sleeve eventually. Never had any problems I could tell. Scary stuff if a plug is building up every time I lube the thing! They ought to warn of that in the maintenance book. The other zerks just produce that crackling noise as the old grease oozes out. I didn't know the one was a closed system.

Waters

If it was a closed system, there wouldn't be a zerk fitting on it. the grease finds it's way out no problem. Just put a pump, maybe two, it, you don't need to use up a tube each time you service the vehicle.

Brian

You are very right. I looked at a Toyota drawing and it's just a male/female connection with a dust sleeve over it. No way it could be sealed and super-compressed. If there's clearance for the yoke to slide, there's room for the grease to squeeze out. I see old grease on the chassis that was flung out at the open end. There is about two inches of exposed (shiny) driveshaft when the truck is parked, but that's got to be its normal state or it couldn't slide.

There are articles on the Web saying that people have fixed driveline clunk by removing the zerk and purging excess grease. It was probably just a matter of waiting until it self-purged, or some other coincidental cause.

Waters

Waters schrieb:

I am very sure you know what you are doing. Good luck!

Cheers, Axel