Vibrating pretty heavily when accelerating

[ObedaTJ]

So I had my local shop replace my transmission skid plate today, everything went normal (or so I thought).

Driving back home, I immediately noticed some vibration. Only when accelerating, then I got on the highway and the Jeep would barely push past 2k RPM and even then it was barely going 40-50 MPH which is weird considering I was easily doing 70-80 MPH this morning. It feels sluggish now, It was literally a perfect ride this morning.
They also did replace 2 O2 sensors. Bank 2 sensor 2 and Bank 2 sensor 1, could this be it?

Could they have messed something up? It’s a 2005 LJ btw

 

[pagrey]

Ya, some O2 sensors use the wrong voltages, especially Bosch. Generally you should use Mopar/NTK. That could be the problem.

 

[Jerry Bransford]

Drivetrain vibrations that only happen while accelerating are commonly caused by the rear pinion angle being too high. Since they had the skidplate off could they have felt compelled to screw with the rear pinion angle somehow? Did they have the rear driveshaft disconnected for any reason?

 

[pagrey]

got on the highway and the Jeep would barely push past 2k RPM and even then it was barely going 40-50 MPH which is weird

This part is what made me suspect something with the sensors. Why did you replace the skid?

 

[ObedaTJ]

Ya, some O2 sensors use the wrong voltages, especially Bosch. Generally you should use Mopar/NTK. That could be the problem.

I just ordered the NTK ones, all four just to get it over with. We’ll see.

 

[ObedaTJ]

The transmission skid plate was rusting so I had another one (not OEM) and decided to finally put it on. Literally started having this issue as soon as I left the shop. I suspect they must’ve messed with something in the process of installing the new skid plate or uninstalling the old one.

 

[pagrey]

What skid, did you do any frame repairs to mount it?

 

[Jerry Bransford]

Did the original skidplate have spacers between it and the the frame that dropped the skid plate down down an inch or so? If so were the spacers reinstalled? It would be common for 1" spacers to have been installed between the frame and skidplate with a 2" suspension lift to stop drivetrain vibrations.

Also is the replacement skidplate an exact OE factory replacement?

 

[pagrey]

What do you bet it's a tuck? Let's see it, a picture is worth...

 

[ObedaTJ]

Okay don’t mind the horrible pictures (it’s night time) I am actually pretty disturbed with what I saw so the skid plate looks normal but the other part I circle in white used to sit bolted in the transmission skid plate.

Now it’s sort of just hanging. Another thing I noticed was one bolt missing holding the transmission skid plate. No part of the frame was repaired during installation as all the frame rust is only surface rust and not rot.

There were no spacers before installing and no spacers now.

 

[pagrey]

Looks like the UCF stock style skid, it can cause issues. I'd replace those sensors and see where you are. I don't think the driveline issues can limit your speed, they just shake but you'll see.

 

[ObedaTJ]

Looks like the UCF stock style skid, it can cause issues. I'd replace those sensors and see where you are. I don't think the driveline issues can limit your speed, they just shake but you'll see.

Replaced sensors with NTK and it improved RPM and speed issues.
However vibration issue is still very present.

You are right that is UCF (included with the jeep from prev owner)
There was spacers included however I don't know if they were for this so I didn't add them.

 

[pagrey]

Glad you have one issue out of the way. I'd bet spacers or a small drop on the skid will fix the other.

 

[ObedaTJ]

Glad you have one issue out of the way. I'd bet spacers or a small drop on the skid will fix the other.

I will give it a shot, thanks a lot!

 

[Mall'er]

You have an LJ, so spacers probably won't help. Spacers for small lifts are generally only for TJs.
Get the skid bolted up properly to the frame, it looks like it is sagging quite a bit, and it it can move you will have vibrations.

How is the transmission mount bolted to the skid? I am not familiar with that skid, but I am used to seeing the mount bolts hang down a bit.

The transmission skid, the front plate that is hanging, should be bolted to the new skid, you may have to drill some holes in the new skid to mount it. Until you do, it can move and probably just make some annoying noises until it falls off.

Looks like your front pinion seal is leaking also.

 

[CharlesHS]

https://undercoverfab.com/extra-cle...ter/72-locker_pump_mount-no_locker_pump_mount

The slots are where the factory mount bolts extend thru and the nuts are recessed in the channel beneath the skid outer surface.