Noticing some vibration in my JK..driveshaft?

MattJK09 · 12-29-2009, 01:32 PM

I have been noticing some vibration at approx. 55-65 mph, mostly when my RPM's are around 1500. It's almost like a "lugging" vibration and I can feel it in the steering wheel and seat / floor. Is this just the OD lugging at low RPM at these speeds? It goes away when I speed up. I am concerened that I "streesed" my driveshaft when installing / uninstalling my BB twice. When I reinstalled my BB the second time, I really noticed that there were some lines (looked like fuel or some type of fluid lines) that were REALLY stretched to the tightest they could be in order for the axle to get low enough for me to squeeze the coils back in. I have to assume that I had the driveshaft under alot of stress. Is this an issue? I know I'm paranoid, but don't like new vibrations coming from underneath. It's a " wa wa wa wa wa" vibration if that makes any sense...

Avian · 12-29-2009, 10:36 PM

I had the same thing, a lugging noise between 50-60 mph that could be felt through the floor, pedals, and wheel as well. Took it to the dealer thinking it was the rear end or t-case....got a new driveshaft. The one they replaced it with looks completely different from the one I had from the factory.

MattJK09 · 12-30-2009, 06:49 AM

Quote:

Originally Posted by Avian

I had the same thing, a lugging noise between 50-60 mph that could be felt through the floor, pedals, and wheel as well. Took it to the dealer thinking it was the rear end or t-case....got a new driveshaft. The one they replaced it with looks completely different from the one I had from the factory.

I wonder if I will get hassled because of my BB lift?

calemasters · 12-30-2009, 09:20 AM

Quote:

Originally Posted by MattJK09

I have been noticing some vibration at approx. 55-65 mph, mostly when my RPM's are around 1500. It's almost like a "lugging" vibration and I can feel it in the steering wheel and seat / floor. Is this just the OD lugging at low RPM at these speeds? It goes away when I speed up. I am concerened that I "streesed" my driveshaft when installing / uninstalling my BB twice. When I reinstalled my BB the second time, I really noticed that there were some lines (looked like fuel or some type of fluid lines) that were REALLY stretched to the tightest they could be in order for the axle to get low enough for me to squeeze the coils back in. I have to assume that I had the driveshaft under alot of stress. Is this an issue? I know I'm paranoid, but don't like new vibrations coming from underneath. It's a " wa wa wa wa wa" vibration if that makes any sense...

If the differential pinion angle has changed, that could induce a harmonic vibration in the drive-line. Make sure the front and rear differential pinion angles are within specification.

MattJK09 · 12-30-2009, 05:49 PM

So is pinion the same as caster? If it is the pinion or caster that is off, wouldn't it vibrate all the time and not just at low rpm's. It goes away when I speed up and it isn't "lugging".

calemasters · 12-30-2009, 08:03 PM

Quote:

Originally Posted by MattJK09

So is pinion the same as caster? If it is the pinion or caster that is off, wouldn't it vibrate all the time and not just at low rpm's. It goes away when I speed up and it isn't "lugging".

For solid axles, yes, changing the pinion angle does change the caster also. Harmonic vibrations can phase in and out as the rotational speed of the driveshaft changes.

JMW1191 · 12-23-2010, 12:14 AM

i just installed 37's on my jeep jk... blew out rear most u-joint, thinking it was causing the vibration i replaced it.. and it is still vibrating. it is coming from the rear end at all speeds. the entire jeep vibrates. What could this be? could the 2inch difference from 35's to 37s really make a difference on the pinion angle?

**RockyClymer** · 12-23-2010, 09:16 AM

If you have a U joint, then you have replaced your rear DS as the stock has two Rzeppa joints which cannot be replaced by themselves. If you have a double cardan rear shaft, then the rear pinion angle MUST be properly set or you will blow the rear joint (most likely anyway) as it is not designed to run at high speed at an improper angle...so, do you have a U joint (double cardon shaft) in the rear? Did you properly set the rear pinion angle (using adj control arms)? If not, then you will need to do it.

bluegrassguitar · 12-23-2010, 01:16 PM

And this is why I've left my JK totally stock. It gets me where I want to go, anyway.

JMW1191 · 12-23-2010, 05:56 PM

i replaced my stock with the rubicon express rear 1310 driveshaft.. sorry should have mentioned that.. took it to the shop today and they told me that all my u joints were blown and the flanges were both so worn that the u joints wouldnt stay put in them... so basically my only choice was to wait to rebuild it or to buy a new one. I am having one overnighted and installed in the morning. Plus all my control arm bushings are shot... i had rubicon express send me a set in october knowing that they would all go eventually.. thanks