I regressed my zerk fittings with waterproof Lucas Marine grease, so of course I purged the old grease out (pumped red Lucas grease through until all of the old, black stuff stopped coming out and was replaced by the red). There was quite a bit of grease used and cleaned up. I noticed something odd the next morning; I couldn't move my auto trans into drive very easily, couldn't even get the button to depress until I pushed the shifter forward. Once I got it into drive, the shifter seemed to move into reverse and drive with hesitation. After driving about 10 miles or so, it seemed fine. Could this have been due to there being excess grease in and around the rear propellor shaft or u joints?

 

No.

 

Side not on greasing your u-joints I just had some replaced and was talking to the guy who owned the transmission shop and he was saying that when greasing don't pump too much at one time. He said pressing all that grease through so fast will cause the rubber seals that hold the grease in to prematurely wear and stretch out. Letting the new grease you just put in work its way out more easily and causing u-joint failure. Said just put in a couple or few pumps during your oil change is all you need. However its a little different if they have been submerged in water or there has been a lot of salt on the roads.

 

That is totally not the right way to grease your u-joints. Like was mentioned before, just a few pumps every oil change is more than enough. If you wanted to change the greese in them, to do it right, it would take well over a year at a couple of pumps every oil change to finally get the old grease out.

Keep us posted on how it works out for you, I sure it will help someone else here out.

 

Thanks guys. I actually went by the instructions of the people at the stealership. It seems good now, so here's hoping.

 

So, after posting this, I became paranoid that I had ruined my driveshaft and U-joints. I did some searching around and asked a couple of mechanics. Both mechs said that it's no problem if grease comes out, aside from the fact that excess grease will work it's way out and fling itself all over the underside of my runner. I'll probably call a couple of others tomorrow. There seems to be a similar feeling on forums as well, although there are some with pretty good points against greasing until it comes out. I guess we'll just have to see...

 

BDTB, I recently spent a lot of time researching the topic of vehicle greasing. What I found were many, many opinions on the subject. Here's the conclusions I made...

For U-Joints, apply a *non-Molybdenum* grease until you hear and see a little bit of old grease coming out of *every* seal on the U-Joint. Molybdenum grease, in theory, will damage U-Joints. Pumping in just enough grease so that a little comes out of every seal ensures you've pumped in enough grease, and also tells you that all the seals are still functioning correctly. If you cannot get grease to escape one of the seals, that U-Joint is beginning to fail.

For the slip-yokes (propeller shaft), a Molybdenum grease is typically OK (check the FSM). While greasing the slip-yoke, it should expand a little with each pump. Eventually grease should escape from the seal, letting you know you've pumped in enough grease and that the seal is functioning properly. Here's the really important part: after you see grease escaping the seal, the pressure in the slip-yoke will be at its max, which can lead to transmission damage (vibration/movement isn't absorbed by the slip-yoke; rather, it's transmitted right through the slip-yoke to the transmission). Remove the zerk fitting; this will release the excess pressure and push out excess grease. Once the flow of grease has stopped, replace the zerk fitting.


Disclaimer: the above information is my own personal opinion after reading many other people's opinions and experiences. This is the process I follow and have not had any issues.

 

This could explain why my transmission was acting strangely at first. I observed the movement of the slip-yoke and greased it until a tiny bit came out of the seal. I never removed the zerk fitting though. Good to know in the future.

 

So, removing zerk fittings=easier said than done. It's going to have to be replaced if removed, due to the wrench slipping over the "nut" surface (whatever that's called). So, I took the smallest allan wrench I could readily find and depressed the zerk's 'bead'. I had some grease come out as I 'pumped' the bead in and out with the allen. I then had my friend lightly 'bounce' the rear of the truck up and down, which pushed out a little more grease, but not much. I did, however, observe the proper actuation of the slip-yoke, with the zerk both open and closed while the truck bounced, so that tells me the pressure in the shaft is just dandy. So, in hindsight, I should have relieved the pressure of the slip yoke zerk initially, but it seems it sorted itself out by moving around within the slip yoke as the rear drive shaft spun, possibly at the expense of some additional pressure on the transmission. Fortunately, I didn't hit any large bumps or potholes, so I don't think the pressure on the transmission was any worse than, say, a day of driving on a rutted out trail.

As Catusphile and I saw in researching around, there are many trains of thought on this matter. I'm always glad to get new perspectives on just about everything I engage in. This forum has proven to be a very valuable bank of information.

 

I like the pressure release on the slip yoke idea! Ill have to try that. As for how you recommend the u-joints being done; I would say that is fairly close to what I have been told, a little grease coming out is ok, pumping a lot through just to get it to come out of all the seals is not. If you have one seal that is not letting it our you ar right in that it is probably not working right. What I was getting at was the seals getting stretched by pumping too much. I'm sure yours will be just fine.

 

I was pickin' up what you was layin' down.

 

Yes. Excessive grease has no way to escape, and this could easily lead to your transmission/transfer case getting cracked. That's why the shifter wasn't moving, the shaft was pushing into the transmission with great force.

I've had a post about exactly this problem, with a diagram of how the slip-yoke works. But since the OP didn't search, I'm certainly not going to either.

 

Ahh! Lesson learned!

Guess I am used to large hydraulic equipment.