Highway drone and loud idle?

[holdmybeer]

For my car the upper latch was not well alligned so the door was not locked there. This was not signed by the electric door-open-contacts. So I recomend everybody to check this for your car.

Thanks for the tip. Is this something easily observed? e.g. From the “side” with small door still open?

 

[Karli]

Thanks for the tip. Is this something easily observed? e.g. From the “side” with small door still open?

Optically you probably will not notice it (as me too). When my Greny was in a workshop for fixing the lost small bolt in the transfercase-knob and some other guarantee-issues, the mechanic checked the closed right back door by pulling the upper side back (small door open) and demonstrated it to me. It is easy to see and feel, if there is no locking. He told me, this is a very often observeable fault. It took a few minutes to fix it by adjusting the black earpice with a spanner.

 

[HereinDaRockies]

Amazing investigative work in this thread! @Dave Rosenthal !

I have a slight cyclic drone while applying engine load (even slightly applying pressure on the accelerator) this happens between 75-80mph. Each period of the drone is probably 0.5 sec. If I let go of the gas, the drone stops immediately.

Anyone else experience similar cyclic drone?

 

[Clark Kent]

Hi @Dave Rosenthal

A bump for this thread. Have you been able to make further progress with your investigation? Suspected involvement of the rear door structure/glass @ 46Hz.
Valuable work. Thank you.

 

[Ka-IG]

Amazing investigative work in this thread! @Dave Rosenthal !

I have a slight cyclic drone while applying engine load (even slightly applying pressure on the accelerator) this happens between 75-80mph. Each period of the drone is probably 0.5 sec. If I let go of the gas, the drone stops immediately.

Anyone else experience similar cyclic drone?

I’ve had my Grenadier for 4 months now, and this is exactly what I’m experiencing. A low frequency intermittent hum at about 0.7 sec apart. It goes away when dropping to 7th or removing foot off the throttle, and going to 85-90mph makes the hum more constant.

 

[zvakanaka]

I think I’ve commented on this before in a previous posting. My car fortunately doesn’t really suffer from this issue and at 12400 miles the engine is smooth as butter including at idle.
As I mentioned before I believe the noise is harmonic distortion in the exhaust system although there is also a very slight tranny whine at speed.