can a U-joint be bad and have no signs of it ?

[marvin]

i have a 78 last night i was going down the road and it started whining @ about 40mph but would stop @about 60-65mph so i looked over everything all seemed fine sort of sounded like it was the rear end so i changed the gear oil didn't help checked my transfer case level was fine but i changed it also so while i'm going change crazy i did the front diff just to keep it all on track together so i'm down to the U-joints but they look fine it shifts fine but when it whines it has a a small vibe what do you guys think ?

 

[STLKIKN]

Marvin,

It is possible to have a u-joint that whines and doesen't really show any signs of abuse, the most likely cause of it would be a dry cap...

More than likely though, the double cardan (cv) at the t case is starting to wear.

Usually the cause of that is lack of lubrication to the centring ball between the u joints. ( the cv will also cause a vibe)

you may need to pull the d shaft out to check for wear, or if you can find a grease gun needle, you can look for the zerk (usually an inset type) give it a shot of grease and see if the problem lessens or goes away.

 

[marvin]

thanks /emoticons/[email protected] 2x" width="20" height="20" />

 

[marvin]

now that i think about it just after i got it i had a Ujoint go out and it broke the ****** thing @ the cv and i had to buy a new one so those are pretty new about a year but when i was replacing them i got a new one for the rear but they gave me the wrong one so i put the old one back in and now that i look around i still have the wrong one in my tool box that i never took back i'm going to replace the back one and hope that fixes it :wacko: O and some thing i should have said before i did some wheeling sat and this started wed if that helps any

 

[Broncobuster]

the trac loc broke in my 78 and started whining like you said yours did.

 

[marvin]

what is that ? bad news ?

 

[RTM]

Bad gears will whine as well which more than likely would be from bad pinion bearings.

 

[marvin]

sorry i haven't got back to this sooner i have been working a lot of over time but any ways the axle seal on the driver side just started leaking just after my last post so it has been sitting but i'm about to jump into it in the next few days any advice with that in mind the seal that is my plan is to do the bearing while it is out and what do you think my chances of the gears being shot are if they got to dry??

 

[Runnin'OnEmpty]

Marvin, if a diff runs dry of oil, the gears will score. A whining noise will result from this, even after the gear oil is topped off. A diff whine will usually get louder when you let off the gas and let the engine 'brake' the vehicle.

Since the seal is leaking, maybe it's just a bad wheel bearing.

Good luck.

 

[marvin]

thanks and you say louder when you let off it mine is gets less loud when i let off