Vibration/Noise when accelerating hard from Idle

[Heckler1963]

I'm getting a vibration/growling noise on hard acceleration. I can feel it in my feet when I get on it hard. Did a three inch lift about three months ago had drive line vibration that was resolved with a transfer case drop. This is a totally different noise that just started last week. I checked that all bolts I touched when I installed the lift were tight. Checked motor mounts and tranny mount all looks good. Going to check flex plate and converter next. If anyone has any ideas of anything else I could check I would greatly appreciate it. Thanks

[4.3LXJ]

The first thing I would look at is the exhaust hitting something. That and the torque converter bolts are the most common things

[Heckler1963]

Checked exhaust everything is tight and nothing is touching. Going to check converter bolts next.

[cantab27]

drop front drive shaft and go for a drive ..................

[slvmart]

Does the frequency of the vibration/growling seem to track the rpm ?

Condition of Front drive axle u-joints, unit bearings, and ring and pinion ?

[Heckler1963]

No it doesn't seem to follow RPMs it sounds more like drive train noise.

[4.3LXJ]

Which transfer case do you have?

[Heckler1963]

Not sure. How can I tell?

[XJ Wheeler]

If it says "Full time" on the indicator for the t-case you have a np 242, if not then it's a np231. Found this handy image online to aid in my explanation.9480

Sent via messenger pigeon. I talk, he types.

[Heckler1963]

Thanks I guess I have an NP231.

[Heckler1963]

UPDATE: I dropped front driveshaft checked u-joints and took it for a ride, still had noise. Checked all of the flex plate bolts were tight, still have noise.

[nhidden31]

Check the transmission mount. Someone had posted a video of, what I feel is your issue, and it ended up being a worn transmission mount. Mine had the vibration(not so much a noise) and that's what it was.

[Heckler1963]

Thanks mine looks good but I will try changing it.

[Heckler1963]

Changed the transmission mount and the vibration is gone. Thanks very much.