Lubed driveshaft, slip yoke question

[aawolf]

I lubed my 2000 automatic's driveshaft Friday before heading out on a 1100 mile drive over the weekend. I followed this guide. I have a question though. The guide says:

Of note, the slip yoke takes about 5 or 6 pumps of grease.

When pumping in the grease I got the expected "crackle" and seeping grease from fittings on 6 of the 8 locations. However on the two slip yokes, I never heard/saw and grease "crackling" out as I pumped, and I ended up needing to pump quite a few times (12-16?). Eventually, I started getting small amounts of grease seeping out of the fittings on the grease gun itself (the hose connections). It was hard for me to tell what portion of each pump was still entering the zerk fitting, and what portion was being rejected.

One other detail here is that after lubing the driveshaft, my vehicle's mileage and performance in the 70-85mph range increased dramatically. So... this was a very needed maintenance.

I'm wondering if it's just that the previous owner NEVER greased the driveshaft in the vehicle's first 162,000 miles of life, and that these slip yokes were just starving for grease. I didn't want to over do it on Friday, but now that I see a very positive result I'm wondering if the slip yokes could still use more grease.

So question is: is there any risk to getting back under there and being more aggressive with the grease gun? And is this this symptomatic of something needing to be replaced.

 

[cashmoney]

Put grease in until you just start to see the slip yokes expand and then stop. That's it.

 

[aawolf]

I didn't really notice any expansion as I pumped, though I wasn't aware that I should be looking for it. I pumped quite a few times is there a risk of damage/over packing?

 

[cashmoney]

You can do what some folks do and push in the little ball on the zerk if you think you've got to much in there. That will relieve the pressure and bleed off any excess. Mine when I did them must have taken 15-20 pumps to get enough grease in there to start moving them.

 

[StreetCreeper]

I just did mine the other day for the second time in 6 months. I pumped about 47 pumps in before I saw movement. I let a little pressure out by depressing the zerk nipple with a small screwdriver.

Nice and smooth now and no clunk after braking.

 

[shootmymime]

pump pump pump away. if you do fill things up when you flex your suspension it will compress or lengthen the slip yoke, no biggy. pump pump pump away.

if you get too much in there it will just squeeze out when it compresses anyways.

 

[nissanh]

I don't think pumping too much is a good idea. When you go over a bump the length of the axle gets shorter and grease takes its room and leaves no space for the yoke to slide. This will put too much force on the 3rd member (which is steel and can hold the excess pressure) and the transfer case (which is an alloy and can break)

 

[cashmoney]

If it was a totally sealed system I'd agree with you but it's not. Well, not totally unsealed. Either way, unless you fill the joint entirely with grease you shouldn't have any issues.

 

[nissanh]

drive shaft

If it was a totally sealed system I'd agree with you but it's not. Well, not totally unsealed. Either way, unless you fill the joint entirely with grease you shouldn't have any issues.

Grease can make a seal, and with almost zero gap between splines, it is in fact going to act like a seal and would work like a piston.

Pull the spins apart and apply grease and then put back the splines together, see how far you can press. To press it in, you have to remove the grease zerk.

 

[cashmoney]

Grease can make a seal, and with almost zero gap between splines, it is in fact going to act like a seal and would work like a piston.

Pull the spins apart and apply grease and then put back the splines together, see how far you can press. To press it in, you have to remove the grease zerk.

I know how it works and I still stand by the statement and practice of adding grease until the yoke just starts to move and calling it quits and either releasing the pressure from the zerk or not. The yoke will squeeze the excess grease out if it compresses far enough to do that. It's not like you are trying to compress it in to a block of steel.

 

[JayRolla]

I just run enough grease so the yoke slips nice and smooth with no clunking when stopping. From my understanding just enough for smooth operation is what is needed. Not a fully packed yoke. If you have seen inside you will realize how much space you are filling and thats not what is needed just like nissanh has mentioned. But to each his own.

 

[cashmoney]

I just run enough grease so the yoke slips nice and smooth with no clunking when stopping. From my understanding just enough for smooth operation is what is needed. Not a fully packed yoke. If you have seen inside you will realize how much space you are filling and thats not what is needed just like nissanh has mentioned. But to each his own.

Key statement there. End of the day as long as you feel good about it that's all that matters.