Vibration in reverse and park

[imthehink]

I'm stumped, I get vibration only in reverse and park at 1 to 1.5k and then it goes away. I replaced the motor and tranny mounts last summer so those are good. U joints check good as well. Any ideas? Thanks

[uberxj92]

what year, engine, miles on engine, how hard do you abuse it, 4x4 or 4x2? auto or stick?

& mounts can go bad fast sometimes, or they could have been defects.

[imthehink]

93, 4.0, AW4 auto, 151,000 4x4. I definitely don't abuse it hard. Haven't been offroad in awhile, it just gets driven on the weekends right now.

[uberxj92]

go back over your mounts, especially the tranny mount . take a look at the harmonic balancer too. when mine went it vibrated at different speeds & sometimes in reverse or in drive.

[imthehink]

I'm bringing this back as the issue still persists. All mounts are replaced and harmonic balancer is good. Driving and Idle is fine. It seems to only vibrate in reverse and when I give it gas in park or neutral. It's driving me nuts lol. Any insight would be great, thanks.

[Mudderoy]

I'm bringing this back as the issue still persists. All mounts are replaced and harmonic balancer is good. Driving and Idle is fine. It seems to only vibrate in reverse and when I give it gas in park or neutral. It's driving me nuts lol. Any insight would be great, thanks.

Long shot. Have you checked to make sure the torque converter bolts are tight?

[imthehink]

Long shot. Have you checked to make sure the torque converter bolts are tight?

Yes they are tight

[LizardRunner]

is the flex plate straight and true? I had that happen to me once and it was a bugger to locate the freaking bent part causing the vibrations at weird times. Could also be in the tranny its self. but rather unlikely.

[jeepxj95]

could it be the harmonic balancer?

[lifted1994xj]

I would double check your mounts. I had a brand new carquest motor mount go bad in 6 months, it squeaked and caused vibrations

[4.3LXJ]

How long since you tuned it up, especially 02 sensor?

[imthehink]

I tuned it up right after the vibration started. Everything I can possibly think of to cause that has been replaced. I did loosen and retighten the torque converter bolts which seemed to have helped for the most part, but the vibration is still there, not as much before though.

[BlueXJ]

TC fluid may be low,
Motor mounts may be cracked or deteriorated
Tranny mount needs to be rechecked. Loose xmember bolts/missing bolts.
As mentioned harmonic balancer may be backing loose from it's rubber isolator.
Only other thing that comes to mind is a driveshaft out of balance. Does this happen at speed or on a lift?

[imthehink]

Checked all of the above and everything is good. I did retorque the flexplate bolts and that seemed to help a little but its still there a bit. It only does around 1.5k in reverse and park/neutral so the ds is fine. I'll just keep racking my brain lol.

[Mudderoy]

Checked all of the above and everything is good. I did retorque the flexplate bolts and that seemed to help a little but its still there a bit. It only does around 1.5k in reverse and park/neutral so the ds is fine. I'll just keep racking my brain lol.

I wonder if it could be a cracked flex plate? Anyone? Anyone?

[LizardRunner]

At this point I will suggest checking the angles on your transfercase and rearend, it seems that everything else has been either replaced or inspected and found to be good. That pretty much only leaves drive line angles as a possible culprit.

[imthehink]

I changed my exhaust manifold cause it was cracked and the vibration seems to have almost vanished. Now another question lol. After I got everything back together I have a slight exhaust leak, would it hurt to use two manifold gaskets?