CEL, No Code, Rear Clunks

[Jeepoftheseus]

Hey folks,

Yesterday, after the forum helped me rap my head around the lift on my jeep, something unusual happened. I was scooting down the street to pick up some beer when I felt two rear-end clunks. It sort of felt like the first clunk came from the rear right tire and the second clunk from the rear left. almost like shit was breaking off the bottom of the jeep and I was running it over. It was very alarming. My girlfriend felt it too. She thinks it felt more like a transmission issue. The CEL immediately came on and I pulled up to the gas station. Everything idled just fine and I did a quick look around but didn't notice anything. We drove it 5m back home with no issues. In the whole trip I don't think we were ever higher than 3rd gear. And the shifts all felt smooth.

This morning I went out to read the code but nothing is coming up even though the CEL is still on. I got underneath it and im not noticing anything missing. I'm pretty confused. Any insight or tips about where to look or what to do next will be helpful!

 

[Duck Doctor]

Did you use a code reader when attempting to retrieve the fault codes?

 

[lBasket]

I spy with my little eye... A new diff breather hose, and the old one still dangling too?

 

[DuckNut]

I spy with my little eye... A new diff breather hose, and the old one still dangling too?

I saw that too. Lake the way it hangs without obstruction. Driving in the rain would be fun for just so long.

 

[Jeepoftheseus]

I spy with my little eye... A new diff breather hose, and the old one still dangling too?

I think you just solved a mystery that has been perplexing me for a few weeks. I even posted it lol. It dangles from the trim under the wheel well, and I haven't wanted to remove the trim to see where it goes.

 

[Jeepoftheseus]

I saw that too. Lake the way it hangs without obstruction. Driving in the rain would be fun for just so long.

Glad you caught this. Can you tell me what I should do to make sure everything will work correctly?

 

[Jeepoftheseus]

Did you use a code reader when attempting to retrieve the fault codes?

Yeah, I used a bluetoothe top scan. It showed no DTCs present, which I thought was odd.

 

[lBasket]

Glad you caught this. Can you tell me what I should do to make sure everything will work correctly?

Why not just connect the original one

 

[KennethS]

I felt two rear-end clunks. It sort of felt like the first clunk came from the rear right tire and the second clunk from the rear left. almost like shit was breaking off the bottom of the jeep and I was running it over... She thinks it felt more like a transmission issue. The CEL immediately came on

If the CEL came on it has to be something the ECM was actually monitoring. There should be a code, either immediate or stored.
Does your reader show stored codes?

 

[Jeepoftheseus]

Update:

Went to autozone and used their scan tool. Apparently my "Topdon Topscan Lite" can't read these old TJ's or is just defective.

Autozone scan tool said that my P0442 small evap leak code has returned. Oh joy. Maybe the crazy clunks in the back are totally unrelated to the evap code.

 

[DuckNut]

Glad you caught this. Can you tell me what I should do to make sure everything will work correctly?

The vent line dangling from behind the wheel well is zip tied to the filler hose - highland dry.

A properly run vent line has an inverted J in the line. This prevents water intrusion in the case of submersions. One that goes straight up will fill with water if submerged. A vent line with a J will trap air in the line preventing water entry. These types of vents are mandatory on boats to prevent water getting into fuel tanks.

Why don't you remove the other and install the original?