Seems to go away at high speeds but becomes more present as I slow down. Engine RPMs don't matter much... it'll be shuddering and I can put it in neutral and it still happens.

It "feels " like its coming from the rear/center of the truck so I'm guessing driveshaft related. The driveshaft does not have much play in it when I try to rotate it by hand. The u-joints all appear OK. I guess I'd have to take down the DS to see how much play they have in them.

Maybe the center bearing or maybe it just needs a good balancing?

What is involved with replacing the center/carrier bearing?

Any other suggestions?

 

It was a u-joint... So what's the best u-joint replacement?

 

Can't answer which kind to go back with. I replaced 2 of the 3 and put the zerk fitting type in. Later I learn from the brain trust on several web sites that the non zerk fitting type is stronger. ??

At least I can greese these. No problems yet. Its been 25k since installed.

Dave

 

the non greasable ones are not stronger persay, they are however air/water tight.if u dont occasionally grease the greasables, they will rust the needle bearings and u will have a failure. I have NEVER had a failure on a greasable joint, have had several on the nogreaseables.

 

Once mine die I will go with the greaseable U-joints... To much water, snow, mud, sand, weeds, rocks, gravel, etc... This truck goes everywhere... Mostly off the pavement.

So I know my U-joints are take a butt beating from everything listed above! worst yet I can't grease them!

 

Maybe they mean since there is a hole drilled through the yoke they are weaker with the zerk???

 

The only greasable u-joint failures I have ever had was in a 800hp Class 8 off-road race truck. Yes they cracked thru the grease fitting.
We learned that you are "supposed" to put the grease fitting into compression when installing the u-joint. By that I mean you install the u-joint so the driveshaft rotates into the grease fitting.
After doing that, we never had a failure from that point on. Broke a lot of other parts, but never a u-joint again.

 

Could you explain further? Maybe I just can't get my mind around it this early, but wouldn't the grease fitting be in compression no matter where it is located? I'm not getting something here. The only choice I can think of for installing the grease fitting orientation is toward the shaft or away from it, and this is usually decided by accessibility for greasing it.

Thanks,
Chris

 

Stamey

Let me see if I can explain this, not sure how to draw a picture here.

This is explained as if you were looking BACK at the rear end with the driveshaft rotating clockwise.

If you look at the u-joint with the yokes oriented at 12 - 3 - 6 - 9 oclock and the grease fitting at 2 oclock. If you place the drive shaft yokes at 12 and 6 oclock and the rear end yokes at 3 and 9 oclock the grease fitting is in compression. The shaft is rotating clockwise or turning "into" the grease fitting.
Now if the same scenario was to have the grease fitting at the 10 oclock position with the shaft yokes still in the same postion as above,the shaft is rotating clockwise and the u joint is being "pulled" apart from the shaft rotation.

Not sure if you can understand how it was explained. Basically you want the shaft to rotate into the grease fitting or compress the grease fitting.

It sounds kind of strange but we never had a failure afterwards when we put them into compression thru the grease fitting.

Hope it helps

 

Wow, I didn't know that. I have never had one fail by twisting off/breaking, but I probably have not ever had enough torque to make it happen.

Thanks for the explanation. I just hope I remember it when/if I have to replace my own U-joints.

Chris

 

Excellent....makes sense, once you get the picture.

RJ

 

I've had the same kind of vibration for a while and it turned out to be the drive shaft carrier bearing, in finally gave out today, and you talk about shakin, it felt like the truck was coming apart so yall might want to check it every now and then

 

the greaseables are also easier to install.