Too Much Grease in Drive Shaft? (2 Viewers)

[calskibum]

I've had the clunks on shifting many people had written about. After reading the numberous threads, which suggested adding grease to the drive shafts, I asked the dealer to lube the drive shaft a couple of days ago at my oil change (sorry, I had the dealer do the oil change because I thought $19.95 was a good deal for oil change, especially at a dealer). Well, of course they assigned it to what appeared to be a beginner technician for the job (as they usually do on simple oil and lube jobs).

Not only that my drive shaft clunks did not go away, now I've developed a clunk about a second or so after starting from a complete stop. This is similar to alia176 had described in post #26 of this thread (https://forum.ih8mud.com/80-series-tech/21559-driveline-thump-cunk-when-stopping-starting-2.html). My question is, is this caused by them adding too much grease to the drive shaft? After reading all the threads about too much grease in the drive shafts causing damage, I'm getting a bit sleepless.

By the way, when looking under the vehicle, I suspect that the dealer also forgot to put back one of the factory protective plastic covers (similar to a skid plate, but I know better to call them skid plates since they're just plastic), but I just can't say for sure. Does anyone out there still have these plastic factory protective shield on the bottom of their TLC 100s (especially if it's a '99) that they don't mind posting or sending me a picture of what a full set is supposed to look like?

Thanks!

 

[Kigiin]

When was your thunk happening before the re-greasing?

My thunk has been going on for about 30k miles and occurs at the same point as what you describe... a second or so after starting from a complete stop.

 

[arbetrader]

I had the same problem on my cruiser, and virtually every other toyota truck I've owned. I just had a pro lube it (I know I could have done it, but he knew how to do it better). Anyway, problem solved (at least for now) hopefully it lasts a while!!

You should look down there to see if it really was lubed, perhaps the dealer didn't even do it, lol!

 

[calskibum]

I've always had the shift thunk since I bought the truck used 15K ago, but the thunk I got after 1 second or so from complete stop just started after they greased the drive shaft. I saw the tech do it from a distance, but I couldn't tell how much he put in it except that he did quite a few squeeses. After searching around on mud, I found the thread mentioned in my original posting and others talked about the problem possibly being the draft shift binding and releasing. Many threads also talked about "hydrolocking" the drive shafts if too much grease was put in through the zircs and causing transfer case damage.

Now I'm concerned that the new thunk is caused by the tech putting in too much grease since it wasn't there before they lubed the drive shaft. And if so, am I now facing additional concerns about damaging my transfer case. Some people mentioned that it's not a concern about over greasing the drive shaft if the grease is seeping though the seal, but mine is not so I can't tell if the drive shaft is over grease and could't get out because my seal is clogged or the tech didn't put in enough grease for me to worry.

I'm currently on a road trip in Oregon so I couldn't take it back to the dealer to have them checked. I am concerned if I'm doing damage to my TLC by continuing the road trip.

Any thoughts or input?

 

[e9999]

well, there should be some grease seeping out past the seal, the whole point is to grease the splines.
You could unbolt the Prop shaft from the TC (or Diff) and try to push it in to get some grease out past the seal, but that may be very hard. Easier for the short term would be to unscrew the Zirk and let any excess grease out, it'll just squirt out, and you are still left with a non-functional seal that has to be fixed, but at least you won't damage the TC stuff by "hydrolocking".

 

[Jim_Chow]

The slip yoke joint is the only one you need to worry about overgreasing. If you pump too much grease into the U-joint zerks, they old grease just oozes out with a crackling sound. One thing you can try if the slip yoke is overgreased is to remove the zerk, then drive up & down a curb or 5mph speed bumps. If there's excessive grease in there, it should ooze out.

My driveshaft started to clunk at 70K mi AFTER greasing the slip yoke with only 4 pumps of M1 grease! Personally, I think moly grease should work better, as moly is good for sliding surfaces. After 5K miles, the clunk finally went away. My policy now is to under grease the slip yoke (car never sees water).

 

[calskibum]

Thanks for the info. Okay, this may sound stupid, but I'm a newbie...how do you unscrew the zirk? I see the little nipple/nozzle. Do you just unscrew them by hand like the caps on a tire valve or do I need special tools?

 

[e9999]

Thanks for the info. Okay, this may sound stupid, but I'm a newbie...how do you unscrew the zirk? I see the little nipple/nozzle. Do you just unscrew them by hand like the caps on a tire valve or do I need special tools?

I imagine the base of the zirk should have an hex nut machined into it. So use a wrench or socket.

 

[Elijah]

It's either 8mm or 6mm, can't remember.

 

[calskibum]

Thanks everyone for the help!

 

[LCHardriver_02]

Was under the truck yesterday, trying to get to the various zerks along the drive shafts. One thing was that that the things seemed always to be in the wrong position for me to get to them! Will need to move the truck and try again. Hard to do on a driveway. Suggestions are always welcome. Also, did get to one and started applying grease, but never saw any come out. Heck, was not even sure where I would see it come out. Now, this was at the U-joing just off the rear diff. I pumped several times, expecting see something oozing somewhere... nothing. How many times should I expect to pump before I see the old stuff coming out and just for clarification, I am supposed to see old grease coming out, right?

Thanks much,

Jonathan

 

[NMuzj100]

Yes, you should see grease come out and keep pumping until it's new clean grease. At the u-joint it will come out under the caps. On the yoke it will come out where the shafts meet and slide.

 

[LCHardriver_02]

Cool. Just didn't want to over grease anything since, we are traveling at the end of the week. Bad time to have to try and fix bearings!

 

[LCHardriver_02]

OK. I know we have covered this, but was under the truck quite a bit last night trying to get to the $#%!# zerts on the two propeller shafts. What a pain! Especially the front most spider bearings! OK, enough ranting. I also greased the slip shafts, but never saw grease actually exit the shaft seals. Pumped in two 3 oz grease cartridges and was seeing the shaft extending on each pump, so I stopped. Is this normal? Seems like an excessive amount of grease.

 

[hoser]

For the slip joint, people have different thoughts on this. IMO, you have too much grease in the wrong place and could cause damage. The for sure way to do it would be to take the drive shaft apart, clean out the gunk and grease the splines.

 

[syrinxstar]

OK. I know we have covered this, but was under the truck quite a bit last night trying to get to the $#%!# zerts on the two propeller shafts. What a pain! Especially the front most spider bearings! OK, enough ranting. I also greased the slip shafts, but never saw grease actually exit the shaft seals. Pumped in two 3 oz grease cartridges and was seeing the shaft extending on each pump, so I stopped. Is this normal? Seems like an excessive amount of grease.

This is what I did for years on my 80 series (pumping until the shaft moves) and what I did about 2-months ago on our 100. It does fix the driveline clunk for a while (if you have it) -- mine just came back about a week ago.

 

[Tinkerer]

I had the infamous clunk a few seconds after starting to roll from a stop.

First I tried greasing with some generic grease, just a few pumps into the driveshaft spline slip joints (but not overgreasing) plus routine u-joint greasing. Still clunked.

Then I took the rear spline apart because the clunk seemed to be from the rear. There was nothing apparently wrong, some grease inside. But the grease in the spline area seemed somewhat thin, perhaps a result of separation in service.

So I cleaned the spline slip joint internals and put it back together, and greased it again with generic grease, directly on the splines prior to assembly and also a few pumps into the zirk. This seemed to reduce the clunk somewhat, but after a couple weeks it started coming back.

So finally, I overgreased the spline/slip joints with moly grease thru the zirks, until grease was visibly spooging out past the lip seal. This cured the clunk. Have not heard the clunk for a few years now, have not regreased.

Thoughts:

1. The Toyota factory service manual (for LX) says to grease until grease is seen escaping past seals. This may mean it is actually a proper service technique that causes no harm (if manual is correct). Page PR-7:

"HINT: After installation, pump MP grease into each fitting with a grease gun until the grease begins to flow around the oil seal."

(I think "MP" means "multipurpose". This is evidently where Toyota missed it, regarding the need to use moly in this application.)

2. The splines are evidently prone to "stiction": When vehicle is stopped, idling in D and held by brakes, the static angular (torsion) driveshaft load sets the splines semi-stuck together in a nominal axial (driveshaft length) position (due to neutral height of rear end). As soon as vehicle starts to accelerate, rolling from stopped position, the spline contact force increases due to angular (torsion) forces in the driveshaft, at the same time sliding forces between splines increase as the rear driveshaft is compressed by the rear end being forced down as vehicle starts to accelerate. If there is inadequate lubrication in the splines to prevent stiction, they will momentarly stick (static friction) then break free and slide (dynamic friction). This causes the clunk. The solution is to get enough lubrication between spline sliding surfaces to prevent stiction. ("Enough" also means "correct" lubrication - MOLY.)

3. Greasing with only a few pumps does not really force much (if any) grease into the spline area. It may only put a few dollops of grease into the cavity at the end of the internal shaft, with very little (or no) grease being forced into the splines. Therefore greasing must be overgreasing, until grease spooges out past the seal. This will completely fill the cavity and force some grease into the spline area, and also, additional grease will slowly work its way into the splines over time in service helping to keep the splines greased.

Regarding concerns about axial (thrust) force increasing due to overgreasing, and possible resulting damage to bearings in tranny/tcase/differential: (a) The slip joints already exert significant thrust force in service because they are sealed so well that they act like air springs due to air trapped in slip joint cavity, so overgreasing does not create thrust forces where none exist without overgreasing, and (b) the tranny/tcase and differential input bearings will already include thrust bearing provision in their design, because this is a common design factor. As noted I've been running overgreased for a few years now with absolutely no resulting problems.

4. Moly grease MUST be used to alleviate the clunk problem. (Caution: Moly is toxic, don't eat the grease.)

Tinkerer's .02 worth. (Nearly a dissertation but a simple problem really.)

 

[LCHardriver_02]

Well, I think I put in enough grease, but used general Lithium based grease. Have not had the "thunk", but just trying to make sure everything was properly greased, as I am doing the 120K service. The fact that I used 3 3oz tubes between the spiders and the slip joints tells how much I applied. The slip joints were definitely moving, and I pumped several in once I saw the movement, but not until grease catapulted through the seal. This was where I stopped. I may try and apply more, but since we are leaving on a 14 hour "joy" ride down to CA tomorrow morning I will more that likely leave it and watch it closely. My 2002 LC FSM does also state to grease until grease is "freely flowing" but it just seemed like an absolute ton of grease that I was pumping in, plus my arms were getting tired pumping, while laying on my back in the garage. Love the clearance down there though. Bumped my head only once this time! The FSM does state the use of a Lithium based grease for this application, along with the spider bearings.

BTW, is there an easier route to getting to the most front spider bearing and slip shaft zerts? I was snaking my fleible hose in and reaching around the "skid plate" to get to it. the access panel for the oil pan is there but does not line up to allow direct access and there doesn't seem to be another. Anyone remove this huge piece of plastic (skid plate) to get to it easier? What a PITA!

Jonathan

Sorry so long too...

 

[Tinkerer]

<snip>

BTW, is there an easier route to getting to the most front spider bearing and slip shaft zerts? I was snaking my fleible hose in and reaching around the "skid plate" to get to it. the access panel for the oil pan is there but does not line up to allow direct access and there doesn't seem to be another. Anyone remove this huge piece of plastic (skid plate) to get to it easier? What a PITA!

Jonathan

Sorry so long too...

I remove the large plastic splash shield to access the front driveshaft lube points. (Not sure I'd call it a "skid plate"...it wouldn't take too much skidding, methinks...)

See the 100, be the 100...

 

[hankinid]

Thoughts:

(I think "MP" means "multipurpose". This is evidently where Toyota missed it, regarding the need to use moly in this application.)

4. Moly grease MUST be used to alleviate the clunk problem. (Caution: Moly is toxic, don't eat the grease.)

Tinkerer's .02 worth. (Nearly a dissertation but a simple problem really.)

Tinkerer, great post and good analysis...

Can you tell us what brand of grease you used. My u-joints and splines are due for lube & I wanna' get to it over the 3-day weekend.

Thanks

Steve