Heavy Vibration in Reverse only V6 Accord. Head scratcher.

[Gasbuggy]

My 06 accord 3.0 has a sudden gnarly vibration in reverse only, sometimes park if the tension is reverse like (parked on a grade, no emergency brake holding it). I can't pinpoint it but its on the passenger side of the engine (opposite of the transmission) and is more prevalent in the cabin than outside under the hood.

This is an EX-L with the dumb vacuum lined fluid filled engine mounts. Which I eliminated about 50,000 miles ago. Not only that, where possible, I encased new mounts with additional polyurethane so they would be stiffer/hold up longer. At the time I replaced the 3 engine mounts and the upper trans mount. I did not replace the two lower trans mounts because they were fine and still appear to be fine. They are rather puny.

There is no vibration on the front, rear or side engine mount while in reverse against wheel chocks. But the engine itself is vibrating heavily.

I placed a prybar on the engine hoist hook to try to add or remove tension. No change, which I find odd. The engine movement going from drive to reverse is minimal. Before i replaced the mounts it was significantly more and there was no vibration.

I've looked all over the web and haven't had much luck.

I don't believe I can troubleshoot more thoroughly without calling a friend up to sit in the car and cycle back and forth from Park and reverse while its on ramps and I'm underneath it. But the BITOG braintrust usually comes through so I'm posting here.

 

[ctechbob]

Check that side engine mount again. I had one that collapsed just enough that the metal of the mount would make contact with the mounting bracket. It for all the world sounded like some screwed up transmission problem. It would make this really oddball noise juuuuuuussstt before the trans shifted gears, and then would stop.
I scratched my head for a while until I pulled that mount out and found that it didn't really tear, it had just collapsed.

Keep one on hand now since they're the same for both cars and aftermarket has them cheap. Wasn't worth paying for a genuine Honda one.

I ditched the vacuum ones as well. The TL kept eating those, so I went with an Innovative mount there and replacement aftermarket ones in the other two spots.

 

[Gasbuggy]

Check that side engine mount again. I had one that collapsed just enough that the metal of the mount would make contact with the mounting bracket. It for all the world sounded like some screwed up transmission problem. It would make this really oddball noise juuuuuuussstt before the trans shifted gears, and then would stop.
I scratched my head for a while until I pulled that mount out and found that it didn't really tear, it had just collapsed.

Keep one on hand now since they're the same for both cars and aftermarket has them cheap. Wasn't worth paying for a genuine Honda one.

I ditched the vacuum ones as well. The TL kept eating those, so I went with an Innovative mount there and replacement aftermarket ones in the other two spots.

Will do. I run this Honda a bit hard so the mounts do get worked. Imo this engine needs a connection from the strut tower to the engine too. Back in the day someone used to make kits like this.

 

[ctechbob]

Will do. I run this Honda a bit hard so the mounts do get worked. Imo this engine needs a connection from the strut tower to the engine too. Back in the day someone used to make kits like this.

Ever since I went to the Innovative front mount I haven't had any issues, it does vibrate a bit more, but it isn't anything too terrible. I tried the innovative on the front and the rear and .....yea no.. wayy too much vibration for me, especially when the AC kicked on. I don't drive the car a bunch these days, but when I do I'm usally not going to Sunday Church.

The Accord, it just doesn't eat the mounts as bad as the TL did with the bigger motor.

 

[Trav]

I would guess there is a very good possibility for a bad mount. There is no such animal as a good aftermarket engine or trans mount, not one.

 

[panthermike]

I had an issue like that on the Corolla, although the drivetrains are different beasts and these two cars. Basically replaced the motor mounts and it was mostly better but still had a rough vibration especially in reverse. On mine it ended up being the transmission mount, so hard to say though.

And I agree with Trav, absolutely do not get aftermarket mounts. It's expensive to get OE, but if you're planning on keeping the car for some time might as well.

 

[Gasbuggy]

The most significant vibration can be heard through the power steering lines with the stethoscope, which makes no sense.

But the parts cannon is loaded. Some new mounts are on the way.

 

[Vegoose]

Just to ditto what everyone else has said… it’s a bad mount or mounts. I’ve replaced them on a V6 Odyssey and Accord. Both times it was a miracle fix. OEM only on these parts and they are a bit spendy.

 

[Gasbuggy]

Check that side engine mount again. I had one that collapsed just enough that the metal of the mount would make contact with the mounting bracket. It for all the world sounded like some screwed up transmission problem. It would make this really oddball noise juuuuuuussstt before the trans shifted gears, and then would stop.
I scratched my head for a while until I pulled that mount out and found that it didn't really tear, it had just collapsed.

Keep one on hand now since they're the same for both cars and aftermarket has them cheap. Wasn't worth paying for a genuine Honda one.

I ditched the vacuum ones as well. The TL kept eating those, so I went with an Innovative mount there and replacement aftermarket ones in the other two spots.

For whoever this may help, this guy was right on

 

[Lubener]

You replaced engine mounts and if you didn't use OEM mounts, I would be very suspicious of any aftermarket mount causing your your vibration problem.

 

[Gasbuggy]

You replaced engine mounts and if you didn't use OEM mounts, I would be very suspicious of any aftermarket mount causing your your vibration problem.

I replaced most of them with Non OEM mounts many years and 75k ago... The non oem mounts are firmer and more resilient than the fluid filled factory mounts this EX-L came in with, in my opinion. But the aftermarket side mount has a raised collar that eventually began to rub. The mount itself is still good. The 75k on these had alot of hard downshifts and wide open throttle.

 

[JimPghPA]

^ What everyone else said, double down with using OEM engine mounts.

But while you are at it, see if it has rubber Radiator mounts, and if so replace those also if they look at all questionable.

The 2015 CRV had a vibration due to requiring different than original Radiator mounts. So maybe it's something to check if you can't find what's going on.

 

[Lubener]

I replaced most of them with Non OEM mounts many years and 75k ago... The non oem mounts are firmer and more resilient than the fluid filled factory mounts this EX-L came in with, in my opinion. But the aftermarket side mount has a raised collar that eventually began to rub. The mount itself is still good. The 75k on these had alot of hard downshifts and wide open throttle.

Firmer mounts transmit more vibration to the chassis.

 

[Gasbuggy]

Firmer mounts transmit more vibration to the chassis.

Nothing like the metal on metal vibration discussed in here.

And nothing like the poly mounts I put on my previous cammed CTS-V. That was a night and day difference compared to factory.