Clunking in drive train when under load in my 2004 TJ 4.0 auto

[KeaganKing]

I have been driving this Tj for about a year and a half. I am the last child in the family to drive it and we have owned it since 2020.

so let me cut straight to the point. The drivetrain has a severe sounding clunk whenever it is under load. When I tap the throttle while I'm rolling at about 20 MPH, It feels like a clunk happening right above the center console which led me to believing that it has something to do with the transmission. The sound also happens when I change gears from reverse to drive and back. it feels like something has slop in the drivetrain, but I have no idea how to check/ what to check for any of this. It doesn't clunk when the transmission shifts but again only when I tap the throttle at a very specific speed. The U joints feel good on the drive shaft. the Jeep is on a 4 inch skyjacker lift kit which might be relevant because I don't think skyjacker is that amazing from what I've heard? maybe parts that needed to be replaced to help the angle of the rear end and driveshaft etc were not done with the lift kit? just my thoughts.

 

[GregBelleville]

I have been driving this Tj for about a year and a half. I am the last child in the family to drive it and we have owned it since 2020.

so let me cut straight to the point. The drivetrain has a severe sounding clunk whenever it is under load. When I tap the throttle while I'm rolling at about 20 MPH, It feels like a clunk happening right above the center console which led me to believing that it has something to do with the transmission. The sound also happens when I change gears from reverse to drive and back. it feels like something has slop in the drivetrain, but I have no idea how to check/ what to check for any of this. It doesn't clunk when the transmission shifts but again only when I tap the throttle at a very specific speed. The U joints feel good on the drive shaft. the Jeep is on a 4 inch skyjacker lift kit which might be relevant because I don't think skyjacker is that amazing from what I've heard? maybe parts that needed to be replaced to help the angle of the rear end and driveshaft etc were not done with the lift kit? just my thoughts.

If it makes the clunk when shifting from drive to reverse, have you tried getting underneath your rig while someone shifts the trans to see if you can isolate where the noise is coming from? Obviously be safe if you do it, but that's where I would start.

 

[macleanflood]

Mine was completely shot control arm bushings.

-Mac

 

[KeaganKing]

Mine was completely shot control arm bushings.

View attachment 559265

-Mac

Upper or lower? I have considered buying new upper control arm since I already have aftermarket lowers. I actually noticed the clunk sometimes when I press the brakes really hard. And I also think that might be the culprit to my death wobble?

 

[macleanflood]

Upper or lower? I have considered buying new upper control arm since I already have aftermarket lowers. I actually noticed the clunk sometimes when I press the brakes really hard. And I also think that might be the culprit to my death wobble?

All of them. But mine would clunk when you changed velocity. Hit the gas, clunk. Hit the brakes, clunk. Hit a bump, clunk.

Replaced them all with Savvy and it's a completely different Jeep... absolutely fantastic.

If you don't need fancy stock control arms with fresh bushings are cheap.

20 year old rubber...going, going gone. My crank pulley too...

-Mac

 

[Tob]

Check the transmission mount. Could also be control arm bushings as already mentioned.

 

[KeaganKing]

Check the transmission mount. Could also be control arm bushings as already mentioned.

Ive already tried tranny mount and unfortunately im still here. I saw on another forum that it could have to do with my driveshaft splines so i might check that out too.