What happens when you over grease a slip yoke?? (2 Viewers)

[Noshniv]

So I 'think' I made a big problem. So I am asking if anyone has insight on what happens when you over grease a slip yoke?

2013 LX570

I was performing a 90k maintenance my uncle's LX570 and I noticed the spider joints looked bone dry. So I hit it with some grease. No problem. Well when I went to grease the front slip yoke... I didn't know the maintenance procedure has changed from the 100 series to the 200 series. (Note: I did not have the 200 series FSM and I was going off the Land Cruiser 100 FSM slip yoke maintenance where add grease until grease comes out of the seal. After my 'problem occurred, did I search the forum and now the Land Cruiser 200 FSM maintenance procedure is to grease the slip yoke until it starts to extend...) Now comes the interesting part. I kept adding grease to the slip yoke expecting the old grease to come out of the seal (like in my 100 series). The slip yoke extended out 1-1.5 inches and a little bit of grease came out from the seal. GREAT! I'll just pump in a little more and all the old grease will ooze out I thought. Well.... I heard something pop and the slip yoke compress to the original starting point before I started greasing it. I looked to see how much grease I added to the slip yoke... It was 3/4 of a whole grease cartridge!

So now if I add more grease (post pop sound) nothing happens. The slip yoke does not extend anymore. I took it for a test drive and I did not feel any driveshaft vibration. Or any clunking and popping when transitioning from reverse to drive.

The question now... Did something terrible happen? Is there some sort of seal that I broke. I don't really understand what could have happened. I thought grease could only come out of the seal. Is the 200 series driveshaft hollow and now full of grease??

Any help would be appreciated.

 

[Taco2Cruiser]

No harm done. The only thing you’ll have is all that extra grease will be slung up into the body. The yokes will hold what they need, and what is extra will get squished back out under when driving (due to the prop shafts spinning and compressing)

Not like the extra grease all over the place will hurt anything, but if you want, set aside an afternoon and a roll of paper towels to whip it up.

 

[bloc]

You got the front one to extend 1-1.5 inches? Wow.

I don’t think you damaged anything. It’s the rear that can have problems if it is full and you compress the suspension hard. The front only really sees the movement of the transmission and front diff in their rubber mounts. Even if these parts are now loaded up as the truck is driven it’ll work grease out and relieve pressure. Very different than the sudden spike in transfer output bearing load if the rear shaft is rigid when you hit a bump.

I don’t have any clue what the pop was.

 

[Taco2Cruiser]

I don’t think you damaged anything. It’s the rear that can have problems if it is full and you compress the suspension hard.

I don’t have any clue what the pop was.

In my opinion, it’s just not possible to see those conditions.

You would have to stuff the rear prop shaft with grease, then take off down a run way and jump the truck at speed.

What really happens is people over fill their prop shafts. Then they back out of their driveway and... out comes some grease. Then they drive out their neighborhood and... a little more. Then onto a faster road (like 45mph) and hit a bump... and little more. Then a highway, and a little more grease comes out.

I can say that when I was a Toyota tech, we had a guy over greasing shafts for 10+ years (until I was like, “uhhh, what are you doing?” No one ever had an issue. If anything, we never had any prop shaft issues, ever.

So that’s what leads me to believe it’s not bad, it’s just messy and wasteful.

for pops. that’s the air pushing out. Slip joints work both ways. Under compression, they push crap out, but it absolutely can suck air and junk in also. Which is why the 3rd gen Tacoma now has sealed prop shafts. Bet we’ll see sealed props on the next series of cruiser.

 

[chilibit]

Could you not merely use the check ball on the zerk fitting by pushing it in to release pressure? As opposed letting it leak pass seals.

 

[Taco2Cruiser]

Could you not merely use the check ball on the zerk fitting by pushing it in to release pressure? As opposed letting it leak pass seals.

It would definitely help, but I’ve noticed that when grease no longer comes out from pressing in the zerk. The shaft will still sling a ton of grease. And that is from the compression of the prop shaft that @bloc mentioned.

The only way to clear the extra grease cleanly, is to unbolt one side (the transfer case output or the diff input), remove the zerk, and compress the prop with a pry bar.

anything else, you’ll just use up a roll of paper towels and spend an hour on your creeper cleaning grease.

 

[bloc]

It would definitely help, but I’ve noticed that when grease no longer comes out from pressing in the zerk. The shaft will still sling a ton of grease. And that is from the compression of the prop shaft that @bloc mentioned.

The only way to clear the extra grease cleanly, is to unbolt one side (the transfer case output or the diff input), remove the zerk, and compress the prop with a pry bar.

anything else, you’ll just use up a roll of paper towels and spend an hour on your creeper cleaning grease.

it is also centrifugal force slinging it to the outer diameter of the splines and flowing to and out of the seal.

 

[Noshniv]

The pop is what I am scared of. I don't think it's just air getting through. Because now it seems like if I add more grease, there is no movement in the slip yoke. I think I filled the grease chamber to capacity and the seal broke. So now there is no chamber holding grease anymore....

 

[CharlieS]

Please read what I am about to type with a grain of salt because it is an idea that I haven't tried. Can you remove the zerk fitting and compress the slip joint (like with a prybar) to see if you can force any grease out of the cavity through the threaded hole where the grease fitting was installed?

 

[Taco2Cruiser]

The pop is what I am scared of. I don't think it's just air getting through. Because now it seems like if I add more grease, there is no movement in the slip yoke. I think I filled the grease chamber to capacity and the seal broke. So now there is no chamber holding grease anymore....

So when you add more grease, there is no movement of the slip AND grease just now freely comes out the splines?

 

[bloc]

Yeah. No seal means it just squeezes out of the slip area.

The only other place for it to go is into the driveshaft itself, and both the male and female sides of the slip yoke are solid steel. Unlikely.

 

[radman]

I can say that when I was a Toyota tech, we had a guy over greasing shafts for 10+ years (until I was like, “uhhh, what are you doing?” No one ever had an issue. If anything, we never had any prop shaft issues, ever.

So that’s what leads me to believe it’s not bad, it’s just messy and wasteful.

Not trying to fight, but this comment contradicts a comment from another thread:

"For those that don’t know, It is EXTREMELY important that you not put too much grease into the slip yoke. Filling this area completely with grease prevents the driveshaft from shortening with normal suspension movement. This can quickly destroy your transfer case output shaft bearings and even diff pinion bearings. Bad news. "

Is this one of those things that has been debated for a while or too much Grease = too much extension on the shaft = too much force on transfer case/ joints?

 

[LINUS]

I didn’t read the replies.

Unscrew your zerk, jack the axle a bit to replicate cycle, then rescrew the zerk fitting in.

Next time just a simple single pump / movement on the splines - is exactly enough.

 

[bloc]

OP had issues with their front shaft.. jacking anywhere won’t make a difference.

 

[DesertLC09]

I made this mistake, and I have some bad news.
I did the same mistake, I read the 100 manual. Did exactly what you did to the front and rear shafts.
As I arrived home I started googling further and I knew what I did was wrong, I ran outside and removed both slip yoke fittings, grease started squirting out with bubbles. Paying a closed look at the transfer case/front shaft flange I see a drip of transfer case oil!
Left the zerk open and drove the car around the neighborhood on some bumps, more grease flowed out as the yoke compresses while driving.
Re installed the zerks and I though everything was fine, no more transfer case oil drips. Fast forward about three months. All of a sudden, a huge leak of transfer case oil is flowing out of the front flange on the transfer case.
Fortunatly it was a simple fix, costed me part 90311-50039 and transfer case fill up + crush washers. 2 hours labor.
The technician said the leak is unrelated, but I am very confident that the extra pressure put too much load on the bearing and caused some flex that damaged front output shaft seal, possible pushed it too much in and caused it to rub with the bearings or something like that.
Since your (yoke seal?) popped and released the pressure before you drove that might have saved you. Unfortunately for me I drove the car with everything fully compressed and under pressure, I was even hearing some humming noise. I am still worried about the rear doing the same but I think the rear output seal is made to handle tougher loads since of the live axle causing it to extend and contract all the time compared to the front that is connected to a virtually static IFS.

 

[LINUS]

OP had issues with their front shaft.. jacking anywhere won’t make a difference.

I guess I should have read then, glad I admitted it from the jump.
Egg, meet my face

 

[Taco2Cruiser]

Not trying to fight, but this comment contradicts a comment from another thread:

"For those that don’t know, It is EXTREMELY important that you not put too much grease into the slip yoke. Filling this area completely with grease prevents the driveshaft from shortening with normal suspension movement. This can quickly destroy your transfer case output shaft bearings and even diff pinion bearings. Bad news. "

Is this one of those things that has been debated for a while or too much Grease = too much extension only shaft = too much force on transfer case/ joints?

I also hope that I don’t come off as trying to start a fight. Let me know if I seem that way.

I feel that a lot of comments (in any forum, digital or live) by people that have some experience, but it may be limited in scope. It’s a tough balance of formal education and repetitive experiences, while NEVER acting like “well, I’ve don this for years... so I know more” attitude.

That said, I can’t come to a conclusion where a non-hydraulic application will win the fight against precision fit parts that are pressed with bearings.

Then when I take some expertises, mud racing in Florida. We were over filling prop shafts to simply get all the mud out and after a while, just leaving it in there and forcing it out the splines. 120k miles on a daily driving capable mud truck with factory Toyota 4 cyl components (but a Chevy 350 with 500+ hp) never had a bearing issue. Then working at the Toyota dealership, never saw a problem.

So is it a good idea to overfill? No. But I don’t see how it is doom and gloom if you do.

But let’s look at this comment below...

The technician said the leak is unrelated, but I am very confident that the extra pressure put too much load on the bearing and caused some flex that damaged front output shaft seal, possible pushed it too much in and caused it to rub with the bearings or something like that.

@DesertLC09 I would have to agree with the technician. It’s was coincidence.

The seal is about a half inch away from the bearing. If the seal moved that much (which really means the flange and the shaft moved inward and would NOT just be able to bounce back into perfect position), you would have shattered the bearings and then the gears would of also gotten crewed up from the rotation inside the case.

Back to @radman, so this is what I see. And I’m not trying to be a jerk @DesertLC09 but this is where is see the information gets muddied.

What if desertLC was the kinda guy that then started actively telling people you’ll blow up your cases if you overfill your prop shafts.

But what is that persons qualifications?
He didn’t do it right from the first point.
He had to pay someone else to do the work so doesn’t know how it actually works.
Then says comments about how the technician was wrong, but follows with a comment about seal to bearing clearances that are absolutely wrong.

This is where is where true information becomes harder and harder to find. Because it is hard to regulate information without becoming a jerk. Like I just did to @DesertLC09. I’m sorry about that.

This post right here is why I am less and less on mud, because I see a lot of just wrong opinions. It’s not advice or information, it’s just opinions.

And I feel like I’m always the one Debby downer that is just trying to correct people, but then I come off as the “know it all jerk.”

 

[bloc]

jerk.

kidding.. I wish you posted more. Your level of experience is hard to come by.

and personally, I don’t care whether it comes off as rude, I want the best information available to everyone.

 

[DesertLC09]

What if desertLC was the kinda guy that then started actively telling people you’ll blow up your cases if you overfill your prop shafts.

But what is that persons qualifications?
He didn’t do it right from the first point.
He had to pay someone else to do the work so doesn’t know how it actually works.
Then says comments about how the technician was wrong, but follows with a comment about seal to bearing clearances that are absolutely wrong.

This is where is where true information becomes harder and harder to find. Because it is hard to regulate information without becoming a jerk. Like I just did to @DesertLC09. I’m sorry about that.

This post right here is why I am less and less on mud, because I see a lot of just wrong opinions. It’s not advice or information, it’s just opinions.

And I feel like I’m always the one Debby downer that is just trying to correct people, but then I come off as the “know it all jerk.”

I had my first thread on me greasing up my prop shaft, I did not do it myself first of all, hence why I drove it back home. The users claimed that my over greasing of the shaft will destroy the bearings.
Secondly, I did not say the tech was wrong, I only gave my story of how the issue started. I had other users tell me that over greasing was bad, also combined with the humming noise I was getting while I was driving back after over greasing, then the drips of transfer case oil that completely stopped after I relieved the pressure in the prop shaft.
I said it was POSSIBLE that the over greasing caused damage to the seal, I never said it was definitive.
My experience was provided as a story that could help others who might have had similar experiences put the strings together and form an opinion.
If you pay close attention to the post you will see that the only information given was the story and my personal opinion, I never claimed anything was definitive or as hard fact.

 

[radman]

kidding.. I wish you posted more. Your level of experience is hard to come by.

and personally, I don’t care whether it comes off as rude, I want the best information available to everyone.

Word. @Taco2Cruiser , your experience speaks for itself! Which is why i used non-hardening form-a-gasket on my roof rack while everyone else recommended RTV.

I greased up my shafts yesterday and used a piece of blue tape help me see when the slip yoke started moving (per the fsm), but i went ahead and stopped after 7-8 pumps and no movement... I figured it was better to stop. When i came back to wipe up a few minutes later, the shaft had definitely moved. I panicked a little, removed the zerks and cycled the AHC, but then decided that I wasn't going to loose sleep over it. I still have 40k miles left on the extended warranty, so we'll see what happens. However, in your experience, i'll be fine!

Thanks for sharing all your knowledge.