Following a PM schedule on the 100 series is very import in having a well running reliable rig. It also reduce the chance of major issue arising and unexpected cost for repairs. Fluids & lubes is the biggest part of maintaining, coolant being the most important IMHO. But lubing is also very important.
The most overlooked lube point by shops, is the propeller shafts. In post #51 I showed one picture and lightly touched on lubing the propeller shaft slide yokes. Failure to keep the slide yoke lubed will result in a drive-line clunk. Failure to lube spiders and they will fail.
The following post will be dedicated to lubing the six points on front and rear propeller shafts (AKA drive shafts) spider joint and slide yokes.
Notice, FSM states "until grease begins to flow around the seal", although this is during assembly, same hold true during PM lubing. It is standard procedure to pump in grease until we see clean grease following, pushing old grease out. That said we must take special care when lubing the slide yokes, not to build excessive pressure in cavity of yoke.
A little History to help understand the propeller shafts:
Toyota and Lexus were replacing a number of propeller shaft under warrant in early years. I suppose they felt it was some defect that replacing corrected a thunk/clunk, it didn't. Some shops became aware excessive pressure was at least part of the problem. In fact some Lexus Dealer shop's I know of (probably Toyota also), would drill a very small hole in back plate of slide yoke. This was to alleviate pressure in yoke. This is where the “over greasing" statement comes from Dealers. The reasons we build so much pressure in the slide yoke, is our seal are a double lipped seals, with one lip pointed inward and one outward. These seal are so tight that air can barely escape pass them. If too much grease was pumped in they would create a great deal of pressure. The expanding slide yoke of propeller shaft would press on transfer case & differential, even more so with each bump in the road. So it was believed we get a thunk from this.
To help keep from creating and over grease condition, we lube with weight of vehicle on wheels, as opposed to on a lift with wheel hanging down. Reason is, as wheel hang lower, like when AHC in "H", the slide yoke is extended. This opens up cavity in slide yokes more than when vehicle in a neutral stance, allowing more grease in. Then vehicle is lowered put wheels on ground, creating a great pressure from this over greased condition. If seal didn’t allow grease to freely flow pass at this point, a great deal of pressure is built up in cavity of yoke putting pressure on transfer case and differential.
So many stop lubing or under lubed which lead to a condition called
Stiction. This is the most common cause of the clunk. Propeller shaft "clunk", is most common heard when braking but not coming to full stop then pressing the gas pedal without delay. Or letting of gas pedal then pressing again without delay.
In Snowy’ s thread post #51 you’ll see I made a note there, that I use some #1 NGLI moly grease mixed with the #2 NGLI. I find this #1 moly helps reduce or eliminate thunk/clunk especially with very tight seals. IMHO the moly helps in two ways, one it seems to fills the ridges or teeth along the spline of the slide yoke shaft. Kind of interesting they have these micro teeth on shaft, hundreds of them circling the shaft, engineers had some reasons for these that's I'll not speculate on here. Second, it seem the moly works its way under the inner seal lip, creating micro cavities/tunnels, air and grease can then escape from between the particles of moly. At least that's my theory. The thinner number #1 NGLI grease also aids in the flow of grease getting to and under the seal. Once I've used the #1 moly, I'll switch back to #2 grease for following PMs each 5K miles thereafter. Note: lube daily in deep sand or long water crossing.
So far every rig I've worked on had a drive line clunk, that lubing corrected. Most of these the slide yokes were either very dry or completely dry of grease. I've developed a procedure for lubing these dry shaft's that takes time. But once I've got them well lubed and working well, it takes only a few minutes to do each subsequent PM lubing. The factory Schedule Maintenance Guide (SMG), has a mileage and time table which guide us. I use the more restrictive 5K miles interval and tweak based on my findings and observation.
The technique I use to is to pump grease in; is to start with spider joint, greasing until i see clean grease flow pass seals. Then I grease slide yoke until it starts extending (about 1/8"). As it extends about 1/8" it reveals clean/silver shaft. I then rub some grease (taken from spider flow) on seal lip and shaft area. I then wait until yoke collapse back, which relieves pressure before pumping in any more grease, then a pump to extend shaft back out about an 1/8" again, and wait. I keep repeating this pulse/pumping action until new grease passes seal. It is very import to go slow, and not to lose patients. If shaft does not retract/collapse on any pause, I stop pumping. If grease starts to follow then stops, I stop pumping in grease.
In any case I then remove then grease zerk (grease nipple/fitting), and put extra weight on vehicle. This is to press out excess grease so when driving hitting bumps in the road, it won't pound the transfer case or differentials. With AHC this is so easy, as I raise to "H" to lube, makes getting under very easy. Then remove grease zerks and lower to "L" when done. Raise again and replace grease zerks, do not over tighten zerk (about 3 to 5ft-lbf of torque).
Turn down your volume, my compressor is running and it's so loud. You'll see at very end of video some grease flowed passed the seal. This one was a very dry propeller shaft and tight seal. I use the pulse/pump technique here as you can see.
Here you see the grease zerk removed and how much grease came back out as I lowered AHC to "L' in this LX470. Without AHC one can jump on rear bumper. I jump/press on upper radiator support at front, as don't like stepping on the front bumper.
With time and miles these seals become worn and actually work better at allowing grease to pass. The picture below is Snowy where you can see the grease passed the seals during lubing. Grease passed relatively easy, which is nice. But this also means it MAY (not will) need grease a little more often the 5k miles intervals. The red grease is M1 )Mobil 1 #2) the purple is Amsoil #1 w/moly
In Snowy I would recommend just using the more common #2 NGLI grease for now. This it’s what most all shop have in there grease guns. I like the Mobil One synthetic #2 NGLI grease, a little more costly but it’s top shelve. Since I used a lighter grease (#1) first time, it may have a shortten time between intervals, before clunk/thunk observed. It will probably go more miles between lubing by using the thicker #2 NGLI from now foward.
Once the slide yokes are working well and regular lubed, it only takes 5 to 10 pump with the grease gun and you'll see some grease pass the seals. Then lower to rig to "L". If more grease passes seal as it lowers, you will not need to remove the grease zerk.
Notes:
- Always wipe off grease zerk to clean head before attaching grease gun. You don't want to pump in dirt that may be cover the zerk.
- Always check torque of propeller shaft bolts at each service.
A few of the many links on the propeller shafts:
The OFFICIAL clunk/thunk driveshaft thread
Lubing propeller shaft Risky (AKA Drive Shaft)
Too Much Grease in Drive Shaft?
Not 20, because I did have 4 new from my last box supplier sent, that I replaced the locking lugs with.
