Vibration at 70 MPH - Help

[eastmentCTD600]

I have a vibration at 70 MPH which blurs the traffic I see in the rear-view mirror. Under 70 MPH seems to be fine, but not perfect.

• When I remove the front driveshaft the vibration goes away completely up to 104MPH - smooth as silk.
• I had the front driveshaft rebuilt; when I re-installed it the vibration came back.
• I've had the front shaft balanced a total of 4 times: 3 times by the shaft rebuilder, then I got frustrated and had it balanced again by another major and reputable shop. Vibration persists.

I also have some minor radial slop in the front output of the T-case. I don't know if this is the cause of the problem or if the slop exacerbates a marginally balanced shaft.

Therefore I need to look at another truck to determine if the slop in the T-case front output is normal or excessive.

Could someone in Colorado in the Denver/Golden/Lakewood area with a 2003-2005 Ram 2500 4x4, QC, LB please contact me (PM or post) so I can look at your truck. All I need to do is grab the front T-case output and check radial play; additionally I would need to know if the truck has any vibrations at speed.

Can someone please help?

Thanks in advance,
Eric

 

[Prairie Dog]

Wish I could help but vibes at 70 are so common that I've got it to (74 mph with my bigger tires). Mine does it even without the front DS and I have replaced everything that spins under the truck - EVERYTHING!!! #@$%!

Good luck!

Scott

 

[Regcabguy]

Might be time for a freespin kit and be done with it.

 

[rscurtis]

X2 on what Regcabguy said.

 

[eastmentCTD600]

Might be time for a freespin kit and be done with it.

Hindsight is 20/20, but I just installed new wheel joints and new unit bearings. That and I do like the convenience of dial-a-drive with the truck.

Anyone in the denver area? Help!

 

[Ozymandias]

Check the rear Driveshaft, there is sometimes a silly interference between those to shafts.
Had this once on my jeep, did front shaft like you three times, didn't solve the problem, without shaft it run fine.
Shortly after a U-joint on the rear shaft disintegrated completely - must be bad long before (binding) and I just didn't noticed it.


And something to think about it, is it a fast vibration you have or a slow vibration, so you can determine which part of the driveline makes the noise.

Oh, and my TC Frontoutput has also a little play, measured at the shaft flange its around 0.2-0.4mm play, I can fell it by hand but barely "see" the play.

 

[sag2]

I have written responses to quite a few 70 mph vibration posts on the older trucks. You need to balance both shafts on the truck after getting the runout at the ends of the shafts to less than .008 inches. Get three hose clamps to fit both shaft diameters and find a road you can get up to speed and stop to get under the truck safely. Do a search if you want the detailed instructions, but it has been quite a few years. Fixed dozens if not hundreds of them in the day.

 

[eastmentCTD600]

Ozymandias - thank for the info. It is a fast vibe (driveshaft speed). The rear shaft is good (single piece 5" aluminum unit.

My front TC output flange has 0.005-0.007" radial play, so slightly less than yours.

How do you like your truetrac in the front diff? Did you re-use stock gears or buy new R&P set? That's my next job...

Sag2
The hose clam method is next if a 5th rebalance and checkup can't remedy this issue (different shop).

I'm really trying to determine if the vibe comes from the shaft or a sloppy t-case output which might allow the shaft to end up in a non-concentric orbit at high speed. The vibe magically appears at 70+mph almost like a switch. This makes me wonder if the shaft is slightly out of balance and ends up vibrating at high speed because the TC output slop allows it to achieve a non-centered orbit at a certain speed. Just a theory...

 

[Ozymandias]

Does the vibe change if you go 4x4?

And an other question - is the truck lifted? Did you check the driveline angles, is the front U-joint at 0,5°????

The TrueTrac is a nice device in the front axle, you never notice it works, except you go through whatever nature kicks in your way.

 

[sag2]

Don't waste the money balancing the shaft again. An hour on the road with your assometer and the hose clamps and you will either make it better or it will not change. I have had a couple trucks that I never was able to fix completely.

 

[MarkEkberg]

Friend of mine with a 05 just went through this on a trip. He ended up needing a new rear shaft or at least that what he was told. New rear shaft fixed the problem.