Eats rear U-joints

[FordGuy100]

My truck goes through them like no tommorow...whats the deal? This will be the third one in the past 12 months.

No burn outs, no dumping the clutch, or anything. Suppose its driveshaft angle?

I've been buying the NAPA premium ones, though they have the grease fitting in them (which I hear are weaker) but still...

Anyone else have this problem?

 

[Diesel JD]

Hey Justin, how are you determining they're bad? I have the same U-joints, and really haven't kept much attention on them.

 

[BIG DAVE]

My truck goes through them like no tommorow...whats the deal? This will be the third one in the past 12 months.

No burn outs, no dumping the clutch, or anything. Suppose its driveshaft angle?

I've been buying the NAPA premium ones, though they have the grease fitting in them (which I hear are weaker) but still...

Anyone else have this problem?

Try having your drive line rebalanced.

 

[FordGuy100]

Hey Justin, how are you determining they're bad? I have the same U-joints, and really haven't kept much attention on them.

Well there are symptoms I use to diagnose. Like if I am crusing at 65mph and suddenly let off the throttle there is like a .05second delay in the engine rpm's decreases, then you kinda feel/hear something and then the truck start slowing down. The last two U-joints were so far gone I could get almost get about an eight of a turn of the driveshaft before it stopped. Caps would fall off with the bearings turned into powder.

The first time it went my truck was making a werid noise, kinda sounded like a bad body bushing or something, that one was the worst one, all the caps fell of with zero bearings.

 

[BigRigTech]

Ceck your angles and make sure the driveshaft is phased if you have a 2pc shaft....I would also get the shaft balanced - it may should the issue on the lathe.

 

[Jake S.]

I would check driveline angles first. All you need a magnetic angle gauge, and places like home depot sell them. I will try to find my book with the correct angles.

 

[Full Monte]

This is strange. From the looks of your truck, it doesn't look like you have done anything to change the drive-line angles. Have you? Is it stock? If your drive line angles look good, I would have the balance on the shafts checked by a qualified drive-line mechanic. These guys are most often found in shops that shorten or lengthen drive shafts for a living.

Assuming the drive shafts are not out of balance, I would then start looking at the drive shaft mounts to the truck. Are they loose? What about the transmission and engine mounts? Is it possible that the engine/transmission are moving around and causing the drive shaft to wear?

 

[LCAM-01XA]

Being a 4x4 truck, would that have a slip-joint driveshaft, like a Bronco only larger? That slip joint may have developed slop causing excessive vibrations that kill the U-joints...

 

[Wanderer-rrorc]

when you install the joint in the driveshaft...is it EXCESSIVLY tight?

I have actually bent the yoke ears on driveshafts before using a press...if its not just right the assembly will slide around or be bound up and bur nout...

also..what grease??? I use wheelbearing grease in mine...made the mistake many many years ago to use white lithium on wheel bearings...they didnt last long till I discovered my novice mistake...

 

[65sixbanger]

I go through u joints like crazy also, they start squeking real bad, fron joints go out even worse...

 

[87crewdually]

If you continually drive through deep water it will also wipe them out quicker because the water will wash out the grease and then cause the failure.

 

[FordGuy100]

I dont drive through deep water, I havent even really mudded it in the last year. Putting U-joints in they arent excessivly tight, about what they should be. I greased them up with a water resistant wheel bearing grease (was in the grease gun from greasing the boats wheels bearings...) so I think that would be ok.

And nope, no change to the angle of the driveshaft, stock height truck with a little taller tire.

 

[Ironman03R]

Check the pinion yolk and straps. I had one on my plow truck that had a bad yolk that was crushing the caps and weraing out the joints.

 

[RLDSL]

When you pres the new joints into the yoke, do you back press them and give the yokes a few good whacks with a hammer to relieve stress on the yoke? If you just press the caps into position , the thing can be under a lot of stress that you don't realize and it can eat them up prematuraly.

 

[FordGuy100]

When you pres the new joints into the yoke, do you back press them and give the yokes a few good whacks with a hammer to relieve stress on the yoke? If you just press the caps into position , the thing can be under a lot of stress that you don't realize and it can eat them up prematuraly.

Yup, dad always taught me to do that. Just followed his instructions. Once in give them a couple good whacks to work all the stresses out.