Jeep made a BANG... BANG... sound
loud enough the jeep rolling down the highway behind me heard it
Edit: Driveline origin, not a basic backfire
90 YJ, i6, 5sp Man (AX15???), NP231, manual lockouts, ARB's front & rear, 35" tires
It's working fine but I'm curious as to what might have made the noise.
I was offroad in 4-high (neither ARB engaged) and came onto a highway and parked alongside the clear/dry asphalt roadway to disengage the lockouts. Another Jeep and I decided to visit another local trail up the road about three miles so I re-engaged the front lockouts and pulled onto the highway.
Rolling a mile to the first stop sign I noticed more wheel vibration than typical and remembered I was in 4-high. I pulled to the roadside, came to a complete stop, and selected 2-high. Back onto the highway, up to perhaps 30-40MPH, clear-dry asphalt, I heard a LOUD "BANG... BANG" and pulled over right quick.
No fluids on the ground. No parts hanging or laying on the ground. All looks as it should be. I disengaged the front lockouts and continued on my/our way. All else worked as normal for the rest of the day (trail, 4-low, dual ARB's engaged with four wheels spinning in deep snow, 4-high, all's good). Back on the road, disengage lockouts, 2-high, highway home. No issues.
What could have caused the noise? 2wd/4wd engage/disengage connection popping out (finally disengaging after I started moving) - but why two bangs vs. just one? xFer case chain hopping a tooth (or two)? Other? Impending doom or just "one of those quite rare day things"?
I didn't notice the gearshifts bouncing when it happened, fwiw.