Tailshaft, too much grease not good.

[stevend34]

Hi people,

I've heard it said that if you put too much grease into a tailshaft it puts too much pressure on diff and can cause issues.
I,Ve also heard it said that you should pump the grease through until it squirts out the spline.

These contradict as to get grease to squirt out you need to build up a good amount of pressure.

What's your thoughts on this?

[jonfromhamilton]

Assuming you mean unis. And if there is a pathway to ambient then there will be pretty much no pressure.
The mechanical displacement of grease will cause zero wear its a non issue imo.

Just make sure the main lip on your seal faces inward towards the unijoint

[gwagensteve]

No, Steve means the slip joint.

I wouldn't go crazy with the grease. In a sierra excessive grease will pop the cap out the end of the splined end.

I just wipe some grease on mine when I have my driveshafts apart.

[stevend34]

Yeh slip joint. Ok thanks for that

What about on other cars, my cruiser for example, same deal?

[gwagensteve]

Not sure/can't recall how what will happen if you over grease a cruiser shaft, but I can easily understand how its possible to "lock up" a driveshaft (preventing it plunging) and this will put large thrust loads on the pinion. If these loads overwhelm the preload from the crush sleeve, you'll loose preload.

It's an extreme/unlikely scenario and depends on there being lots of plunge as the suspension compresses, but it's possible.

Steve.

[porter.8.luke]

In the ag world we try to move the old contaminated grease out with the fresh as the shaft plung should move freely. The problem I have come across in when the splines fill with sand and old grease and wear the splines. So as a rule I pull back the rubber sheath and clean the goo off and give it a plunge to move the fresh stuff out.