Bad Vibes

[Jason’s KJ]

Hi Newbie here, I’ll get right to it. I’ve been having vibrations only when under power all speeds. I put it in neutral and the vibes go away. I currently have the rear diff cover off and will change the fluid. Every thing look ok in there. tires where balanced within the last few months. And driveline feel tight. Transmission was rebuilt in 2018. Any suggestions will be appreciated.

 

[LibertyTC]

Welcome to the forums.
The rear diff dino 85w-90 gear lube should be fresh every 40k miles. What year is your Jeep?
If your Jeep has a trac-lok rear diff it absolutely requires a 4 oz bottle of Mopar limited slip additive to the gear oil.
I probably would want to start by checking the u joints .
Are the u joints real hot after a hwy run?
There is also a companion flange that's off the front propshaft to inspect for tight & leaks etc.
Will get you more info, once I know what year you have.

 

[Jason’s KJ]

Welcome to the forums.
The rear diff dino 85w-90 gear lube should be fresh every 40k miles. What year is your Jeep?
If your Jeep has a trac-lok rear diff it absolutely requires a 4 oz bottle of Mopar limited slip additive to the gear oil.
I probably would want to start by checking the u joints .
Are the u joints real hot after a hwy run?
There is also a companion flange that's off the front propshaft to inspect for tight & leaks etc.
Will get you more info, once I know what year you have.

Thanks for your help it was the u-joints going to change out the gear oil also. Adding the 4 ounces off additive