Topic: Sealed U-Joints Wear Out?

[chrisfranklin]

Was looking at this better mileage article at Petersens http://www.4wheeloffroad.com/techarticles/engine/131_0709_4x4_fuel_saving_tips/friction_and_resistance.html

Wasn't looking for better mileage, just scanning for anything I hadn't read before. 
Anyway, the article mentioned U-Joints wearing out and causing friction in the drive train, thus sapping mileage. 

My YJ is over 150k and running the stock, sealed U-Joints.  I looked at a couple of forums and one guy commented that the lubrication in sealed U-Joints dries up after 30,000 miles!  He claimed the zerk-fitted aftermarket versions -- standard on older vehicles -- need regular maintenance but will last forever (provided you don't bust them). 

I am figuring I will get under the Jeep, check for any drive shaft play.  But even if I detect none, I'd still wonder if are any of you guys are the habit of replacing sealed U-Joints every few years on the assumption that their internal lubrication has expired?   

I personally wouldn't be surprised if mine have seen better days. 

[aw12345]

About the only way to really know if the U joints are good is to see if the rotate well when the drive shaft is out.
Quite often there is no play on older U joints but they move really stiff, which means no grease and generally brinneling on fhe u joint cross and yes this would cause unwanted friction in the driveline

[chrisfranklin]

Hey Art,  thanks.  Yeah, that's kind of what I was figuring.   I think I'll get to changing them down the road if I am working on something else in the drive-shaft vicinity.

[Mozman68]

When mine went bad last week you could not tell by grabbing the drive shaft....felt nice and tight.  Bad joints really throw it out of balance which really affected my power transfer to the rear wheels.

Since I had mine fixed it seems like I gained 20hp...Jeep runs so quiet and smooth it's scary.

[chrisfranklin]

The underside of my Jeep is not in front of me at the moment and I was having a little trouble digging this info up in a search.

But if you were replacing all the U-Joints on any Wrangler how many would you be talking?   

Say 6 for the drive shafts -- 2 for each shaft? (By the way, are these all the same size?)

Then 2 for the front axle?   (These are probably sized differently from the drive shaft versions).



 

[aw12345]

Chris I doubt you have a cv shaft in your YJ so 4- 1310 u joints will do fpr the fromt drive shaft it depends the later ones like the tj use 2- 297x or 760 u joints and those little buggers are expensive before you go hog wild just take the shaft loose on one end and move the u joints if the are stiff or jerky replace them

[chrisfranklin]

I'll do that Art.  But I am still going to go hog wild any chance I get.

[Jesse-James]

I used sealed joints, better seal to keep water out and one less thing to forget about greasing. All in all they are cheap and easy to replace anyway so if they wear out a little quicker I'm not too concerned.