I had my car up on the lift the other day to change the oil, and I noticed that around the rear u-joint there was some grease all over the underside of the car. It really looked like it'd been flung out of the rear ujoint, and it didnt smell like gear oil, so I'm assuming the grease came from the ujoint. Anyway, I dont hear any clunk when I put the car in gear, so I'm wondering, is it safe to drive on for a while until I can find time to fix it?

 

i'd suspect it's gear oil and not from the u joint. either blowing out the rear end vent or from a seal leaking. i'd check the gear oil level and if i suspected the u joint was bad i'd replace it. i just bought spicer HD u joint for a checy truck and was under 20 dollars, auto zone ought to be less than 10

 

if the u joint is greasable then it may be grease that was flung off the joint that had squeezed out.

 

Check the play in the ujoint by grabbing the drive shaft and turning it, you will beable to see how much play is in the ujoint. There shouldnt be any, if there is, its deffinatly bad. If its still all together its pretty safe to drive as long as you dont pound on it or hit high speeds. I drove with a cracked ujoint for 2 days in my truck before I could fix it, and it held up ok. If you do replace it do like ede said and get the spicer HD, kicks *** on the regular ones.

Kevin

 

I don't think this is oil or grease at all!
Both my camaros had this "grease" in and around the trans tunnel at the rear and the rear firewall. After much smelling and poking around we discovered it to be a rustproofer wax that is put on at the factory. The heat from the exhaust and rear diff causes it to melt and stay sticky. It looks like grease and feels like grease but it isn't.
I spent a good few hours removing this stuff on my 86 camaro show car a couple of years ago with a hot air paint stripper. The paint underneath was spotless!
IF there is no noise or clunking etc, leave well alone!

If you want a few photos of this I am sure I can find some.

Don't worry!

Hope this helps.
Andy.

 

I'm pretty sure it came from the ujoint. I know it's not gear oil because the pinion seal is completely dry, and the grease is a little too far foreward. It's got that look of something that has been flung out of something that rotates, you know what I mean. The ujoints dont' have zerks to grease them, they are the factory joints.

 

If they're the factory joints, then they were garbage the minute they rolled off the production line. Of course they're no good now that they've had some use. I thought you were talking about some kind of decent ones, with grease fittings, and somebody had just put too much grease in them, and it had got flung off like it will naturally do.

Get new ones.

 

if your u-joints are bad all you would have to do is drive it around for a few minutes, put it up on the lift and stick your finger on them. if its warm, its weraing out. if its hot, its shot

 

Does anyone know the part number for the HD U-joints? I need t replace mine and not really sure what to ask for at Auto Zone or anywhere else. Thanks.

 

Just ask for serviceable U-Joints. A-Z sells different kinds even Spicer. Whats funny is the non serviceable ones are more expensive and total POS. Someone was nice enough to put new Spicer serviceable U-Joints in my dirve shaft that I got from the pick N pull $5.