Popping sound when in reverse

[Nate 2002 TJ]

Hey yall,
I have a 2002 Wrangler 4.0 engine with automatic transmission. Started it up today and threw it in reverse to back out of the garage before letting the engine warm up. When I put it in reverse there was a rapid popping sound. Any other gear and there wasn’t a sound only reverse. I let it warm up and then just threw it into neutral to roll down my driveway. On my way back I had to throw it in reverse again. No popping sound however i found when i pressed the accelerator while in reverse the popping sound came back. (idk if this had something to do with the engine being heated up already or not but that was the only difference. The popping sound was very rapid but it was consistent almost like a very sped up beat. it was not spontaneous or random. I had my brother listen to the engine area (it is definitely coming from the front) and he said he thought it was near the general area of where the furthest right most wheel is for the serpentine belt. I tried asking him to listen closer and even get halfway under the jeep to listen but he didn’t want to. he also doesn’t rlly have any experience working on cars so I am not for sure how accurate his description of where the sound was coming from was since he was like 3 feet away from the jeep while “listening”. any ideas as to what could be causing the popping sound?

 

[macleanflood]

What's your transmission fluid level look like? How does the fluid look? How many miles? Any recollection as to when it was last flushed or serviced?

Sounds like you might need to drop the pan and look at the fluid.

But...I have a suspicion that a u joint could make that noise.

-Mac

 

[Nate 2002 TJ]

What's your transmission fluid level look like? How does the fluid look? How many miles? Any recollection as to when it was last flushed or serviced?

Sounds like you might need to drop the pan and look at the fluid.

But...I have a suspicion that a u joint could make that noise.

-Mac

I did not check the level however I replaced all the transmission fluid about 6 months back and I have not seen any leaks since. I am worried it could be a gear going bad since it only happens when in reverse.

 

[macleanflood]

Totally agree with that diagnosis but I'd be checking all the u joints, checking torque on all the control arms, track bars, etc.

Wouldn't want to drop the pan on a transmission or pay for a rebuild to find out it's a loose bolt, right?

-Mac

 

[Nate 2002 TJ]

Totally agree with that diagnosis but I'd be checking all the u joints, checking torque on all the control arms, track bars, etc.

Wouldn't want to drop the pan on a transmission or pay for a rebuild to find out it's a loose bolt, right?

-Mac

Ended up being the fan shroud. it was broke at the bottom and the previous owner had installed a bracket to hold it together. one of the screws had came out causing the fan to hit the fan shroud sometimes. I re-attatched the bracket and will be ordering a new fan shroud so i don’t have this problem in the future.