..... I had this issue on a very very minor level before I did the LC Coil/ball-joint spacer lift. Got the lift done and started driving it around yesterday. At highway speeds, there is no issue/noise/vibe under acceleration or constant speed.

But when I let off the gas... It sounds like a mix of a Jake brake and hitting a rumble strip... There is a vibration, but it's not a big bad shaky vibration.... But it IS very loud...in a humming/droning kind of way. The noise is much more noticeable than the actual vibration....It feels like the old lady left her "personal massager" on high speed under my seat.

Thoughts?

I don't know if it's driveline or an exhaust rattle or what.... I will try to get it on video tomorrow.

 

I would check the drive line. If that sucker's out of spec by too much you can kiss the U Joints good bye. However they are only a 15 dollar part but the worst case is you lose the drive shaft, transfer case, pinion, or diff. and those are slightly more expensive. If it turns out your drive shaft is rattling because of the pinion angle, look into getting some wedges to counteract the lift by putting it back into the correct degree of operation. I'm not sure what degree the drive shaft should be at but I'm sure someone will chime in with that soon.

 

Sounds exactly like whats wrong with mine. I need to replace my ujoints. Here is the thread I started not too long ago
https://www.yotatech.com/forums/f116...-decel-249072/

 

did you get an alignment after the lift? if not, there's your problem.

if you had the problem before hand, then it's also possible your wheels have come out of balance.

I'd get your wheels balanced and an alignment first before you start replacing parts.

 

did you adjust your axle after your LC lift? your LSPV and panhard are definitely off.

as far as the front goes, if you didn't get an alignment thats an issue too.

 

I have the panhard bar drop bracket, but did not have time to complete that part of the project. It will probably have to wait until next weekend. In the meantime, I'll hit it with some PB Blaster during the week and report back to ya.

Hopefully that's it.

 

I would check all the u-joints, slip joint and the two flanges at the t-case and pinion. Likely one of more is loose and causing the vibrations. That is the usual cause of vibes when letting off the gas as you have just taken all the load off those parts and with nothing holding them tight, anything loose will vibrate. And the panhard drop may help as that will help center the axle and correct the u-joint angle at the bottom of the shaft.