lol, yeah what DiscoMike said...

That double-cardon is a bugger indeed.

And mike said IF it's a u-joint. I wanted to say something but held my breath. The two or three u-joint problems I have heard about, one of those being mine, is vibration at high-road speeds. Vibration just before a gear change is a new one to me. Take a look at your rubber guibo while you are down there also. You need to change out those two u-joints if they don't have grease fittings definitely, but you may have some broader issue. Don't be upset if it still does it after you change out the u-joints. And keep us updated if you have the time!

 

I just finished replacing my joints. The centerball joint seemed to be the easiest part. If you are confident that you can do regular u-joints correctly and get everything seated nicely as far as cups and clips, it shouldn't be a problem.I did mine with alarge vice, an assortment of large socketsand box wrenches (big enough for the cups to fit into) and a slide hammer. There were some tricky parts that I could help you with if you have trouble though (like grinding a slide hammer hook to fit it into the centering ball - which you would not be able to do if you rent one).

 

Foot note to the topic - Is there a recommended milage to replace the U-joints or inspection method?

MWmG

 

From what I have read, the factory ujoints tend to grenade somewhere around 90k miles, I think. I have heardthata rust colored film around the joints is a bad sign. If you can grab the shaft on each side of the joint, twist it and feel any give, that's a bad sign. I noticed a very slight vibration in my steering wheel that disappeared when I took the shaft off. We'll see if it's still there after I reinstall the shaft, it could be just the design of the shaft and the angles involved I suppose.
Once I got the shaft off, I felt a definite 'dead' spot when twisting a joint.

 

Mine starting causing vibrations between 75-85 MPH by 60k. Replace them if they don't have grease fittings as soon as possible.

 

Very few people ever think about their drive shafts when it come time for maintance. If your u-joints have grease fittings and you lube them every 12,000 miles or once a year, they will last forever, or nearly. Don't lube themm then you loose them.

 

Not tyring to hi-jack the thread, but I've got a quick question re: drivesahfts and vibrations. I've got an '03SE7, 42.5K under cPO warranty, I've been getting a vibration occationally btwn 35 and 40 (not always), and then a significant vibration btwn 75 and 80. I'm planning on bringing my truck in for a head gasket replacements (and alaundry list of little issues - that way there's onyl one payment of my dedicutible), but I'm curious, besides explaining the vibration should I request I driveshaft/u-joint inspection while I've got itin???? (Also planning on having them do a coolant system check as I can't keep the coolant reservoir full, never drops more than a 1/4-inch below full line, but still a concern).

Any help is appreciated. Thanks.

 

Ask them to inspect your u-joints, and tell them about your vibrations.If your u-joints in the double-cardon (hooke's joint) have no grease fittings,ask the mechanics to change them out while you are there with a set that has grease fittings. That is strange with your coolant res, I dunno. If it is staying level, I want to say you are fine, it's just the system. A coolant pressure check can always bring peace of mind though

 

The vibration you are describing is a tire balance issue. When tires are out of balance it might show up, lets say at 30MPH, it will the happen again at 60 and 90 MPH. Time to go see the tire dealer.
As for you head gasket replacement, order a set of 8mm Magnacor plug wires and have the dealer install them while your intake manifold is off, even if they charge you a little extra, it is worth it.
Order the wires at Cerrones/LRRFourms.com, talk to Tony at 650-365-4145

 

Finally reinstalled my shaft - I am now vibration free.