Bad U-joints?

[lispeej]

So, before I run off to the parts store to buy new u-joints, I thought I'd get some inputs.
First of all, recently, I am getting some rumbling noise coming from either under or towards the front of the truck. It feels and sounds a lot like when a wheel bearing is going bad.
So, therefore I replaced my wheel bearings...thinking that was it. No luck. The rumbling is still there. My diagnosis was wrong.
The rumbling noise comes and goes. Sometimes I can hear/feel it at low speeds and also at high speeds. When I the rumbling noise comes on, whether I lead off the gas pedal or not, it is still there.
I am sure it can be anything at this point, but I am hoping it is something more simple like the u-joints going bad.
I have read several posts and my symptons seem to of the same as bad u-joints.

Just a few questions:

1. Is it bad u joints?
2. If it is bad u joints, in addition to replacing the u-joints, what else should I replace while I'm in there?
3.If it's not bad u-joints, what else can it be?

Let me know if I need to clarify anything.

 

[arndog123]

I'd pull the front shaft off and lock the CDL and see if the problem is still there. You'll need to pull it anyway to replace the joints. Check to see if there's enough oil in the front diff too.

 

[lispeej]

I'd pull the front shaft off and lock the CDL and see if the problem is still there. You'll need to pull it anyway to replace the joints. Check to see if there's enough oil in the front diff too.

I just did all my fluids: tranny, frt&rear diffs, transf case.
I don't know if I'll be able to find out with my cdl locked. It goes too slow. I don't have the 7pin mod yet.
Are you talking about the front drive shaft? Or one of the front axle shafts?

 

[lispeej]

sorry.
What I meant by low speed, was that when driving city streets.

 

[kidglove13]

You dont need 7 pin mod
If you suspect one of the DS's to be the source of the vibes
Leave t-case in high and lock CDL
Then remove the front DS and drive to see if the vibes are gone
Very easy to do

Also at really low speeds a rumbling could indicate a dry spindle bushing as well

 

[lispeej]

You dont need 7 pin mod
If you suspect one of the DS's to be the source of the vibes
Leave t-case in high and lock CDL
Then remove the front DS and drive to see if the vibes are gone
Very easy to do

Also at really low speeds a rumbling could indicate a dry spindle bushing as well

I can try that. but I don't suspect one of the ds's to be the source. I suspect one of the u-joints to be the source.

Does anyone know what symptons are with the birfield/knuckle housing low in grease?

 

[kidglove13]

The ujoints are on the drive shaft,
I dont understand what you are saying
To check the knuckle grease level there is a port at the top front of each knuckle that you remove with a 12mm wrench and you can stick a zip tie in there like a dip stick to check the grease level
It should be at least 1/2-3/4 full of grease

 

[lispeej]

The ujoints are on the drive shaft,
I dont understand what you are saying
To check the knuckle grease level there is a port at the top front of each knuckle that you remove with a 12mm wrench and you can stick a zip tie in there like a dip stick to check the grease level
It should be at least 1/2-3/4 full of grease

OK. sorry for the misunderstanding. What I meant was that I am thinking my driveshaft is still good, but the ujoints on the driveshaft are bad.

 

[kidglove13]

Like I said you need to lock your CDL and remove said drive shaft and them drive the truck to see if the vibes are gone and that will answer your question on the bad ujoints
Also you can go under the truck and and try to push and pull up and down on the drive shaft while it is on the truck and see if you feel any abnormal play in the ujoints or your slip yoke
If you remove the DS then you can closely inspect the ujoints for eccessive play

 

[lispeej]

ok...thx

 

[lispeej]

front drive shaft is removed. so far the vibes have gone away. the front u-joint of the front drive shaft is so stiff that it only pivots one way. the rear one moves freely both ways. I would have to say it is the front u-joint for now.
So, now with the shaft out, how about the slip yoke? What is the recommended thing to do at this point?
Would others go ahead and replace the rear drive shaft u-joints as well,,,,or just do the fronts and call it a day?

 

[kidglove13]

Are all the joints original?
If so I would replace them all for piece of mind
That is what I did way back when
And you can do the same with the rear shaft as you did with the front
You just keep the CDL locked and you can drive around with either front or rear wheel drive while each shaft gets repaired
You could pull apart the slipyoke and clean it out and regrease it and put it back together and then hit it with a grease gun after you put it back on the truck
If you put grease in it with a grease gun before you re install it it will be a real bitch to put back on because you will not be able to collapse it enough to get it on
Ask me how I know this

 

[SiRaDuDe]

I just did all my fluids: tranny, frt&rear diffs, transf case.
I don't know if I'll be able to find out with my cdl locked. It goes too slow. I don't have the 7pin mod yet.

Were you able to lock your CDL without have a CDL button? I dont know if '97 came with the CDL button option...

Make sure you locked it!... If you are driving without 1 DriveShaft and you have NOT locked your CDL you can cause damage to your VC in the long term.

Just incase you dont understand, in order to lock your CDL when your Truck has NO cdl button, you will have to turn on key(ignition), put your Transfer Case in LOW (this locks your Center Diff) you should see light in dash... now you need to PULL the fuse that goes to the Diff Lock (this keeps the Center Diff from unlocking) now you can put your Transfer back in HIGH, and drive freely.

That was just a brief description from memory, just want to be sure you have done that before driving too much without locking your Center Diff.

 

[muathoj]

Hello brother,

Just got done with my front driveshaft. U-joints when about to go and caught it in time. My symptoms were at first a ching-leng type of noise for a few months. After that I started get vibes during city driving @ 35-45 and fast rattling @ 70-75 mph. With the latter the vibes were so bad the coin tray made noise also.

Took out the front shaft, replace u-joint with oem u-joint (strongest of all options.) Had the shaft itself /calibrated. And then my issues when away.

 

[kidglove13]

From what the OP said he did not do the 7 pin mod
I was assuming he had a cdl switch installed
Maybe not
X2 you definitly need to have the CDL locked to drive without a drive shaft

 

[SiRaDuDe]

If the OP is doing the test in LOW Transfer case Gear, he is locked and OK.

If he's doing the tests in HIGH transfer case gear, then yes he should lock the DIFF via the instructions above, if he does not have a CDL button.

Everybody has made clear in all posts that the CDL has to be locked, I just wanted to be sure that he understood completely.

 

[Rwhat]

DO NOT replace the U joints with "Autoparts" U joints. Do the OEM joints. About $57 a piece from Cdan.

My 2 cents.

 

[98 SNAKE EATER]

front drive shaft is removed. so far the vibes have gone away. the front u-joint of the front drive shaft is so stiff that it only pivots one way.

For the past few weeks, I've been getting a slight vibe from the front end above 85mph

Front joint had a little play when I checked on Friday, so I ordered up a new joint and when I pulled the yoke a few hours ago, the pivot was very loose one way and extremely tight the other

After removing the retainer clips, I noticed one of the cups was spinning freely and was so worn that slid right out without using the press

Replaced it with a new toyo joint and she's smooth as silk again

 

[kidglove13]

For the past few weeks, I've been getting a slight vibe from the front end above 85mph

Front joint had a little play when I checked on Friday, so I ordered up a new joint and when I pulled the yoke a few hours ago, the pivot was very loose one way and extremely tight the other

After removing the retainer clips, I noticed one of the cups was spinning freely and was so worn that slid right out without using the press

Replaced it with a new toyo joint and she's smooth as silk again

85mph that is some fast driving for an 80
My 80 never sees anything much above 80 at best but mostly granny style 65-70
OEM joints are the only way to go!

 

[98 SNAKE EATER]

85mph that is some fast driving for an 80
My 80 never sees anything much above 80 at best but mostly granny style 65-70
OEM joints are the only way to go!

I drive from NYC to Orlando and back every few weeks....

Anything less than 80mph and you're getting passed like you're standing still