91 Navajo vibration during acceleration

[Salmonaxe]

Recently my 91 Navajo(4x4 Manual Transmission) started vibrating a bunch in the front end when I accelerate. This happened very suddenly after I went over a vibration strip on the side of the highway.

Tires are only a month old. I checked and they had all the wheel weights that were on there before.

Each front wheel had a little bit of slop in them. Pressing on the brake rotor showed a small amount of movement.

I checked the outer bearings on both the front wheels. Looked fine (Based off of what I'd seen in other wheel bearing posts.) I repacked the bearings and tightened the bearing retaining nut to the next position where the key would fit.

No real grooves in the brake rotors. Pads are still thick and are evenly worn. (Guess that self centering keeper is still working.)

After doing this, alignment is better, and steering is more responsive, but the vibration is still there.

Vibration only happens when accelerating. I can take it up to 60mph, put it in neutral and it will run smoothly. Also, it vibrates more at certain speeds.

Just for sh*ts and giggles, I tried it in 4x4. All the vibration stopped. I drove it around like this for a bit and now I've noticed that the left front wheel will "catch" every once and a while. Like the auto locking hub is engaging and disengaging.

I'm thinking that all this might be due to faulty/worn out autolocking hubs. If they are randomly engaging even though my transfer case is set to 2wd, I could see that spinning those driveshafts could potentially create a vibration.

Am I on the right track?

Looking at the manual conversion hub threads, it sounds like getting manual hubs is difficult.

Suggestions? I'd very much so appreciate any help.

 

[Tbars4]

...From what I just read, you are on the right track...:scratch:

...Have you seen this thread on hubs???...It also has some links to diagnosing problems...
http://www.explorerforum.com/forums/showthread.php?t=232754

 

[Salmonaxe]

Alright, cool. Glad to know I'm on track. I'll go over that diagnosis thread.

After looking at the manual conversion thread, I checked out 4wheelparts.com. Now I'm a little confused. Are the way more expensive hub conversion for using jeep parts or something?

http://www.4wheelparts.com/Drivetra...-Kits.aspx?t_c=12&t_s=237&t_pt=5313&t_pl=4535

I have a local 4wheelparts, so I'll probably end up ordering locally. I'm not sure how to determine my spline pattern.

Thanks again!

 

[Tbars4]

...They are similar, but different...The thread I posted above has the correct information..

...Before you go to 4wp, do some price shopping online...They will price match...

..I think I've seen the hubs online for $156 while 4wp wants like $199 per set...The $10 a side from 4wp, spindle nut info is also in the link above...

 

[Salmonaxe]

Oh, I think I get it. Those hubs I linked are for a different axle and spindle type? 30-27spline and 44-30spline. And what I want is one that is 35-27spline.

I guess that 4wheelparts' parts finder isn't perfect. I found the Warn P/N 29071 when I searched by brand.

I'll keep searching for a better deal.

28068X Spicer kit looks like it's not listed on the web. Guess I've got to go in and ask for it directly. (That's how you made it sound in your thread.)

 

[Tbars4]

...That would be correct...You could call and check availability to make sure they have them at their warehouse...

...The 4wp site is good for quick look up on sales items but, their site is more geared for Heeps and newer trucks...

...For cheaper prices, do a google search with the hub P/N #'s..

 

[nitro71]

You can put better ones on there that are a jeep part number, run bout $200 from Amazon.

http://www.amazon.com/Warn-37780-Fl..._1?ie=UTF8&s=automotive&qid=1242267467&sr=8-1

 

[nitro71]

Can you just pull the hub guts so that you have none to see if it's the problem. For some reason it just doesn't sound like a hub problem to me.

 

[Anime]

Ball joints won't usually do it unless they're really trashed, but you could jack up one side of the front and use some kind of long lever to pry up on the tire and see if there's any play at the upper and lower joints. The lowers tend to go first.

You might also check your radius arm bushings and brackets, if they are totally shot the alignment could be ok when it's parked but change when driving, especially under acceleration.

I've found that drivetrain vibration that isn't the tires/wheels is most likely the driveshafts or u-joints. A dry slip joint or a dried out u-joint will give vibration under load or at certain speeds but sometimes stay quiet if driven smoothly.

I wouldn't rule out a middle/rear drivetrain issue that just seems more pronounced in the front, could be anything from a loose bolt, busted engine/tranny mount, etc. Go over everything that moves front to back with a flashlight and hopefully you'll find some clues as to what's going on.

 

[Salmonaxe]

I changed the radius arm bushings about a year ago for some pretty hard polyurethane bushings. Luckily the bracket didn't seem too messed up. They still look good and it handled way better right after I did that work.

How does one remove the guts from the auto hub? It's pretty packed with grease, so I don't know what I'm up against in there.

I'll definitely go over it and check all these things. Sounds like fun...

 

[Salmonaxe]

I did what Nitro said and pulled the hub guts.(At least the internal spline and locking ring. No idea on how to remove the weld spring and other parts.) Now the front end has way less vibration and feels like it controls way better. (Especially at lower speeds) That has me thinking that those hubs were shot.

Still the core vibration when accelerating is there. It now happens at different speeds/rpms. It feels more centralized and moves fore and aft depending on what speed and RPM I'm at.

I am curious how can a the u-joint on a front axle cause vibration if that axle isn't being driven? (2wd)

 

[Alan_V]

I did what Nitro said and pulled the hub guts.(At least the internal spline and locking ring. No idea on how to remove the weld spring and other parts.) Now the front end has way less vibration and feels like it controls way better. (Especially at lower speeds) That has me thinking that those hubs were shot.

Still the core vibration when accelerating is there. It now happens at different speeds/rpms. It feels more centralized and moves fore and aft depending on what speed and RPM I'm at.

I am curious how can a the u-joint on a front axle cause vibration if that axle isn't being driven? (2wd)

It's not driven, but it's still rotating. You have a standard OPEN diff in the front. The axles are always rotating.

 

[Salmonaxe]

It's not driven, but it's still rotating. You have a standard OPEN diff in the front. The axles are always rotating.

So even with the hubs disengaged and the transfer case set to 2wd those axles spin?

 

[Alan_V]

So even with the hubs disengaged and the transfer case set to 2wd those axles spin?

Yup! Surprised me at first too.

 

[nitro71]

If your hubs are disengaged and your in 2wd how do they spin? Just trying to understand more. You'll find the problem eventually I'm sure. You could yank the front drive shaft. Now you'd have that out of the equation. My money is on u-joints on the rear drive shaft.

 

[Tbars4]

...If indeed you still feel the vibration in the front end and you are sure your hubs now are not engaged, I would go back and take a look at the bearings and spindle..

...If you do think it is from somewhere else, this will help you diagnose if it is a u-joint or drive shaft...
http://www.explorerforum.com/forums/showthread.php?t=134134

 

[Alan_V]

So even with the hubs disengaged and the transfer case set to 2wd those axles spin?

OOPSS!!!! WRONG TRUCK!!!

I sat there thinking about what I was talking about, and it dawned on me, it wasn't my truck I was thinking about. A buddy has a Montero Sport and the RF wheel is alwasy engaged to the diff. When he shifts manually, the transfer shifts like a trans and the LF axle is locked into place. The X wheels free wheel. My bad!

 

[Salmonaxe]

After looking everything over, the only thing I found was what looked to be a bad u-joint. The rear u-joint on the driveshaft had about 10 degrees of movement at one bearing cup.

So after some fun with a torch to break free the bolts, I pulled the drive shaft and replaced both the front and rear u-joints. When I got the suspect u-joint apart, there weren't any needle bearing!!! Just a bunch of rusty dust... Afterward the vibration is totally gone. It drives great.

Only things that concern me. I used Autozone's Duralast Gold U-joint. The design didn't seem all that great compared to the stock Spicer's I pulled off. Of course neither had a zerk fitting. For some odd reason, the standard Duralast U-joint looked like it DID have a zerk fitting. But they only had one of those.

My only other concern was that I couldn't get one of the snap rings to fully seat into the groove it was in. It only went in about halfway. No amount of pounding on the bearing cap would get it to seat any further in. I was really careful to not get any needle bearing on the inside of the cap. I guess I'll just watch that snap ring for a while and see if it stays.

 

[Alan_V]

well, I for one am glad you've solved it, seeing that my advancing age has turned my memory to mush.

As for the clips not seating. did you get into the groove and clean them really good? The particles from the disintegrated rollers may have bonded themselves to the metal in the groove.

 

[nitro71]

My money is on u-joints on the rear drive shaft.

LOL! Couldn't help it!