I have a vibration mystery and I'm looking for some help trouble shooting it before I spend the rest of my life savings. (2004 D2 SE 131k)

Its a mild yet harsh vibration that is growing worse at certain speeds (about 35, 70, and 85+ mph). It feels like something is binding - not off balance.

One tech thinks it's the drive shaft. The other shop thinks it's the tires.

So far I have had the tires checked and balanced 3 times. Wheels inspected for bents/true and tires inspected for flat spots.

Plus, I have had the front and rear drive shaft inspected by a top notch shop that does nothing but drive shafts.This lead to the front shaft being rebuilt, spun, balanced, etc. The rear is in ok shape they say.

Plus I changed the trans fluid and filter.

Yet still this vibration presists.

To try and troubleshoot this more I have taken her up to 80 mph ish till I hit the vibration speed (while going down hill on a long hwy stretch ) and put her in neutral. Yet even coasting at this speed the vibration persists!

Before I spend more (the drive shaft shop says they can balance my rear shaft for $145, but y bother?) What else can I do?

I assume coasting in neutral eliminates the engine and transmission?

I've thought of doing the same coasting thing and then putting the transfer case in neutral to remove the t-case for the equation. Is this something that can be done? (and I would not re engage the transfer case until I come to a full stop)

If it's a front or rear diff, how could I tell?

And the front steering knuckles (are they called cv joins on the D2?) What can I do to eliminate them?

Please help! I'm going nuts over this annoying vibration!

 

is the vibration in the seat or the wheel

 

Gah this would drive me insane. But I think trying to shift the transfer case is a bad idea. I wouldn't even try to put my transmission in neutral at that speed for fear of missing neutral and hitting reverse but maybe I just have little bitty testes! Since you have a center-locking diff, remove the front driveshaft and take it for a drive and see if vibration still persists and go from there.

 

Yes! NUTS! NUTS! NUTS!

So its safe to drive her with out front or rear drive shafts and the center diff locked?

But do you mean the rear shaft out? I just had the front re-built, re-balanced, and re-re all else that you could 're'. LOL!

You feel it everywhere - its a whole car vibration, not a steering/warped-rotor-feel-in-the-steering-wheel type of vibration.

Tonight I had the wifey drive me up and down the hwy at speed. I moved from rear passenger side, to rear driver side, and then back again. Then we stopped and I took the passenger seat too. Everywhere I sat while she drove the vibration feel the same, but it was ever so slightly strong when I was in the rear seats then the front.

My fear is that this might be the center diff or the trans. I don't have the $$ to replace them.

Ok, so what is the next step you recommend? Drive without one of the drive shafts in and the CDL locked? If so I will do so this this weekend.

Thank you for your help in advance

 

someone else will know more about it, but yes you can drive it without the front drive shaft. To do so will either confirm or deny issues in the front driveline. A driveshaft can be rebuilt and supposedly balanced, but you never know. I'm not sure what kind of speeds are recommended with Diff-Lock High. There are a number of people that have more information on this, Abran for sure if you want to DM him

 

If you suspect the rear you can remove and operate as a FWD vehicle for your check. As suggested just because the front shaft was recently renewed you shouldn't eliminate it as being suspect and may want to check with it removed if rear shaft not causing vibrations. Recommended DL speed limit not applicable with one shaft removed. Jack-rabbit starts not recommend as one drive taking all the torque.
......

 

I drove an 04' with no front driveshaft for over 1000 miles at So cal freeway driving speeds...

 

GAH' DAHG, 'at-a-boy!

 

So I went to remove the rear drive shaft. One of the bolts that connect the front of the shaft to the drum break was loose. And not just loose, the nut was barely on the bolt!

Going to try it out tonight to see if this is my vibration!

 

Ok. I have removed the rear drive shaft and drove her with the center trans box locked on the highway for about 5 mile. The vibration is MUCH better. But its still present.

Now that I know the removal of the rear drive shaft makes things better (but not 100%) leads me to think my mystery vibration could be from the LT230.

Here is my question: could I have something wrong with my LT230 and driving it in the LOCKED position bypasses the majority of the issue (and thus I have lessen vibration)? After all it is leaking.

Hey all you shadetree mechanics! Do you know the inners of the center trans box to tell me I'm right or wrong??

Thanks! -D