2nd Gen Non-Engine/Transmission Still Shakin’

[BEnglish]

Still Shakin’ ............NEW UPDATE!

In an effort to eliminate the highway speed vibration for my ’98 ½ 3500 4x4,I started with an alignment and the guy at the shop told me I needed new lower control arm bushings, new track bar, new drag link and tie rod. So I got all that stuff from Napa and installed it and went back and got an alignment. While I was there the same guy told me the track bar was no good (play in the frame end ball joint) so I took it back to Napa and got another new one. I have also replaced all six tires, traded out one iffy rim, replaced an iffy unitized bearing in front, replaced the DS carrier bearing, and replaced the shocks with Bilstein’s, and still I have some shaking (about 20% of what I started with) at around 70 MPH. I think my next thing is going to be the bearings in the rear, and/or the rear DS u-joints (the ones I looked at while changing the carrier bearing looked good).

What do ya’ll think? Any advice will be appreciated.

Thanks,

Ben

 

[DCreed]

look for run-out in the axle flanges to indicate a bent axle. or try the truck on jackstands and roll the wheels to see any odd movement.

 

[BEnglish]

look for run-out in the axle flanges to indicate a bent axle. or try the truck on jackstands and roll the wheels to see any odd movement.

thanks, good idea, i will try that

 

[BEnglish]

look for run-out in the axle flanges to indicate a bent axle. or try the truck on jackstands and roll the wheels to see any odd movement.

OK, I chocked the front and put the rear up on jack stands, put it in first and watched the rear tires. Passenger side rolls straight, but the driver has a small movement back and fourth. The rims are verified true and the tires are moving together.

So far on this my trouble shooting has been process of elimination (buying all new stuff). Being of moderate means I would hate to buy a new D80 shaft if I don’t need one.

Is there some other way to test it?

Could it be something else? Breaks?

If I do need a shaft, can you suggest a reasonable seller.

thank you for your help, by the way

and everyone else

 

[DCreed]

If you're seeing some run out then the next thing to look at would be the area behind the wheel where it bolts on to be sure its clean and smooth. then remove the axle and set it across a greased set of "V" blocks and turn it to see if it is bent.

 

[BEnglish]

If you're seeing some run out then the next thing to look at would be the area behind the wheel where it bolts on to be sure its clean and smooth. then remove the axle and set it across a greased set of "V" blocks and turn it to see if it is bent.

thanks, will do

 

[Jefff929]

You said you did the u joints. Often folks don't get that the washers that hold the carrier bearings in line are (shims) dictating the angles from the output shaft to the pumpkin (crs is attacking me, I forget what it is called), if those angles are wrong you may also get a vibration. Something else to check.

 

[BEnglish]

You said you did the u joints. Often folks don't get that the washers that hold the carrier bearings in line are (shims) dictating the angles from the output shaft to the pumpkin (crs is attacking me, I forget what it is called), if those angles are wrong you may also get a vibration. Something else to check.

Thanks for the reply. It’s the differential pinion yoke that you are thinking of.

Actually, I didn’t change the u-joints. I changed the carrier bearing itself. When I had the drive shaft off, I checked the u-joints and they all looked and felt good. The pedestal for the carrier bearing didn’t have any washers on it, so I put it back together the way it came off.

Tonight when I get home I am going to check the rear driver wheel mounting surface and the axle shaft flange and shaft for straightness, on the suggestions from above.







New question; when I had the rear on jack stands, and tried to turn one tire with it in gear, it wouldn’t move. Then when I put it in neutral and turned the tire, they both went the same direction as though there was a locker in there (I know it doesn’t, I have had the cover off to inspect it and clean it out). I know it has a limited slip, but is it engaged all the time or just under power? I am comparing it to a D44 on my Jeep that has a limited slip/selectable locker in the rear and the LS is a cone type that has no friction when unloaded. Is the D80 in the Dodge different? Should the spider gears turn the opposite tire the opposite direction?

And one more question; will it hurt anything to run 80W/90 without a friction modifier?

Thanks for all the help.

Ben

 

[DCreed]

the D80 is a clutch type LSD. If you had the strength of Hercules you could turn it and it would act like an open unit does. unlike most locker types a clutch type is "tunable" in that the clutches can be arranged to tighten or loosen the LSD effect. friction modifier is used to allow the clutches to slip without chatter, so when changing diff fluid (esp. synthetic) try it first, drive around a few tight corners and if you get chatter or tire squeal add some modifier and drive again. it will take some time to mix/distribute the modifier so add accordingly.

 

[BEnglish]

I changed the fluid shortly after I got the truck, a couple of months ago. It was low and looked burned. I didn’t add any modifier then just fresh 80w/90 and have not had any chatter or chirping. Is it OK to leave it like that?

 

[MBrantley]

Check the preload on the rear hub bearings while you are at it, I have owned and worked on many trucks that had loose rear hub bearings ( they are a wear item) it is just one of those things poeple never check...



To check them properly you have to remove tire, the drum or caliper (which ever flavor you have) unbolt the axle shaft flange from the hub and slide it out a bit (some gear lube will come out) and check to see if there is any movement and how easy it spins (there should be some drag on it while rotating and no lateral or axial movement)



I don't have the actual torque spec for the rear hubs maybee someone with a sevice manual can post it?



Matt

 

[Joe Mc]

Pre-Load setting is as follows (per the Dodge Shop Manual for my 99), Torque nut 120 - 140# while turning the assy, and then back of 1/8 turn.

I was reading this post from the beginning and was thinking that I had the same problem in the rear (a vibration), upon inspection I found way too much slack almost 3/4 turn till the nut snugged, it was cured by setting the pre-load correctly - as mentioned above.

I too though about a bent axle and did the V block and dial indicator thing finding a fair amount of out of sink if you will in the middle of one axle. I took it to a guy who knows the Dana units "intimately" he told me the amount I had was "noting" he's seen much more and it never caused any vibration. He told me if the pre-load is set correctly when the axle is bolted to the hub this actually will help straighten it out - the bearing on the hub end (axle bolted to hub) and then where the splined end sits inside the pumpkin will compensate for a good deal. As for me - it was corrected with proper pre-load.

 

[wilsonsh]

Have you figured out the vibration yet? I have it at 40mph pretty bad then it goes away until 65 and stays vibrating up from there. I just installed centramatics so the wheel balance is out of the question and my rims are true... I'm thinking rear wheel bearings but the hubs feel tight. Driveshafts are rebuilt. Gotta get this fixed b4 it starts breaking stuff... it's pretty bad!

 

[BEnglish]

Yesterday I took the side in question (driver rear: I saw the tires moving back and fourth while up in the air) apart and checked the run out of the axle shaft. It had about . 060, so I don’t think that is it. In grabbing the hub and moving it, I found it had quite a bit, what I thought was way too much. I went to take the nut off and couldn’t get it. I have big sockets, but 2 3/8th is too small and 2 7/16th the socket wouldn’t fit into the opening. I went to 3 different auto parts stores and Harbor Freight, but couldn’t find the right size. Oh well, I will find one and get it adjusted ASAP and let yall know the results.

 

[wilsonsh]

Thanks! I crawled under last night and found my transfer case starting to leak so I gotta get this vibration fixed!

 

[BEnglish]

Thanks! I crawled under last night and found my transfer case starting to leak so I gotta get this vibration fixed!

I started another thread to find out what the size of the hub nut so I can adjust the preload on the bearings. I will post up as soon as I find out and get in there to adjust them.

 

[BEnglish]

OK, this past weekend I change the rear bearings to no avail.

Next I am going to get my wife to drive it down the highway and drive around it, looking for movement.

Any more suggestions would help.





So you don't have to read through the whole thread I will list what I have done so far:

-new hub bearing assembly pass front (other one is OK)

-new carrier bearing on rear DS (checked ujoints)

-new tires all around

-new Bilstine shocks all around

-had new tires balanced at least three times

-changed one rim

-new drag link

-new track bar

-alignment

-new lower control arm bushings

-new hub bearings in rear



please, Any more suggestions would help.

 

[Jefff929]

this may seem silly, but I have to ask.



Do you feel the shaking in the steering or in the seat?

 

[BEnglish]

this may seem silly, but I have to ask.



Do you feel the shaking in the steering or in the seat?

Not silly at all.

There is no pronounced shaking in the steering wheel. And it may be the seat but I don’t feel a hard vibration there either.

It is a 4x4 automatic so the only shift lever is the TC lever and it shakes pretty good front to back (the shaking direction could be changed through the linkage though).

And the door panel right next to me seems to be shaking pretty good.

Other than that I cant really nail it down.

 

[Jefff929]

Feeling it in the seat indicates it is probably a back end issue.



drive line or ???



Is it possible to have the mrs drive while you ride in the bed? See if one side or the other is worse.



With all the parts changing already including shocks, I wonder if the ride hight has changed. The trany is mounted to the frame while the diff is mounted to the rear springs, if these angles change too much they can cause a vibration.