I'm one of many chasing down a vibration that started about 30,000 miles ago after the dealer replaced one of my U joints on the rear shaft. I have 3 Precision 351A joints ready to go in but I've noticed a little slop between the 2 rear shafts. Not at the U joint, but at the slip yoke, if thats what it is called.

Should there be any play there at all or could that be my problem. I dont want to have the new joints installed if I have a problem elsewhere. I will have Dodge fix that under warranty and then later on have the Precisions installed. I also notice some movement around the carrier bearing.

What do you guys think.

Thanks
John

 

Let me rephrase my question. Anybody that knows anything about driveshafts, Is it okay to have some slop between 2 shafts at the slip yoke?

 

I can tell you one thing.....anytime you change u joints mark the yokes so you put them back in the same place as original.....if not you could be in for vibration...........

 

I haven't actually looked under my truck yet as it only has 8000 miles on it,...but does the slip yoke have a grease zerk on the side of it?... The older 3/4 and 1 tons used to have a grease zerk on the side of the slip yoke to lubricate it. If not, maybe the yoke has went dry and caused the excessive slop???
I wonder if there is anything in the maintenance manual about a time or mile interval for lubricating the driveline components????

 

It is common for there to be a small amount of rotational play within the slip yoke. If you can feel a significant amount of up and down play then it's a problem. I suspect it's pretty normal on your truck, as I have never seen a slip yoke wear out on these trucks.

Also, I don't think Precision u-joints are much of an upgrade from the stock ones. I would leave whatever's in there alone (probably AAM stockers), until they are a problem, then replace them with non-greasable Spicers. (like the 2nd gen trucks have in the rear.) I've just seen too many Precision joints with slop right from new, and worn out before you know it, due to the poor seals. Just my opinion.

 

[Also, I don't think Precision u-joints are much of an upgrade from the stock ones. I would leave whatever's in there alone (probably AAM stockers), until they are a problem, then replace them with non-greasable Spicers. (like the 2nd gen trucks have in the rear.) I've just seen too many Precision joints with slop right from new, and worn out before you know it, due to the poor seals. Just my opinion.[/QUOTE]


The stock joints are Spicer non greasable. At least that is what they put in when one failed at 23K. I will be installing greasable Precisions so at least I know they will not fail due to being dry. I think maybe the shop got my driveshaft 180 out of sync when they replaced the center joint a while back and that is what is causing the Vib.

 

The problem with greasable U-Joints is they are weaker because of the cross-drilling.

I lube slip joints everytime I change oil, 5,000 miles.

 

On our trucks, I've never seen a drilled u-joint break unless it's subjected to extreme use like sled pulling etc. The usual failure is due to rust or lack of lubrication. Quite often, I'll grease a Precision u-joint and have grease appear at only two or three caps, even on a new joint. Then you know there's a cap or two not receiving any grease, meanwhile you've got the poor seals letting in contaminates so it really doesn't matter how often you grease it.

I've examined the failing u-joints on the 3rd gen trucks, they look much like a Spicer, but slightly different. I believe they are made by AAM.

 

my carrier baring went bad qick it got so bad that the drive line started getting so bad it started hitting the fuel tank schield

 

I've examined the failing u-joints on the 3rd gen trucks, they look much like a Spicer, but slightly different. I believe they are made by AAM.[/QUOTE

I know the one replacement Dodge put in was a spicer. When it was new I was able to read the stamping on the body. Maybe they made a switch or they use spicer as replacement.

 

I'm glad were all having the same problems, sort of...... My truck had a wicked vibration. It turned out that the dealer replaced the ujoints on the rear shaft right before I bought it and oblonged the driveshaft in the vice when they did it. My driveshaft guy said it looked like it was egg shaped. Of course my dealer said they couldn't warranty it becasue someone had ruined the shaft, not dodge's fault. Because I bought the truck from a private individual and no the dealer that had worked on it, I was kinda outta luck. So, one new 4 inch steel precision balanced shaft with heavy duty u-joints later I am vibration free. As a secondary note, my dealer couldn't even figure it out. They replaced the front shaft and told me it was alot better, ha ha ha . I pointed out the driveshaft and then they laughed at me, no warranty.

 

What I said is what I meant...........MARK 'EM BEFORE YOU TAKE 'EM OUT---PUT THEM BACK IN SAME ORIENTATION ---- IT DOES MATTER

 

Later this week I will have a driveshaft shop remove the shaft, install the 3 precision 351A joints and balance the unit. I will report back and let you all know how it drives.

I'm convinced either they installed the shaft 180 out or my driveshaft got tweeked from the failure or the install.