Root Cause Found?... short shifter RATTLE

[Ashikabi]

Originally Posted by NoHaveMSG

The pivot is tight to move but the rattle in the video is from that pivot which I found odd.







Exactly what I was thinking along with replacing the sintered bushing in the IRP with plastic bushing.

I question if replacing a metal bushing with plastic will have durability issues

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[NoHaveMSG]

Originally Posted by Ashikabi

I question if replacing a metal bushing with plastic will have durability issues

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It for sure won't be as durable, I don't think it will be too bad though. I have some fiberglass reinforced nylon options I am looking at from some of the motion control companies I deal with. I am willing to give it a go for science.

[grumpysnapper]

Originally Posted by Ashikabi

I agree with NOMSG. The shaft passing through the seal should not really be able to "rattle" due to the seal itself. Also, that seal can't be replaced with a bushing or it will leak. I think your next test should be to dampen the joints of the floor shift shaft. Obtain or make a soft or flexible washer that can be compressed to add to the pins connecting the shaft. Perhaps some foam or neoprene can be cut into a washer.

If it is the stub shaft then we could look at making a secondary "seal" that would hold the end of the shaft

Yeah, I dont think the internal shaft rattles against the casing as such, but vibrates through the oil seal, then through the first shaft joint. In other words the internal shaft is the actual cause of the vibration, and the sum of the other attached parts are designed to mitigate the vibration on a standard system.

When any single part of that system is compromised from standard, the whole shift system vibrates/rattles.

The engineers even added a "shift lever damper" into the first connecting joint structure.

That said, my first joint doesnt have the play in it that NoHaveMSG has, on mine (and others I've played with) the shaft rod end moves within the seal. But it is possible that most of the boxes I've looked at are fairly low km units (mine included).

I've tried a couple of versions of the soft washer idea, and it doesnt really work too well. I've also tried the opposite idea of (very) hard packing the washers...and that didnt work either.

I also tend to agree that drilling out the entire bush on the first link (below the gear lever), and replacing it with a flexible liner of some sort might be the best option....but very difficult.

I've even considered attaching small containers 3/4 full tungsten (granules) to the main shift control shaft to see if that might dampen the vibration....

[Ashikabi]

Originally Posted by grumpysnapper

Yeah, I dont think the internal shaft rattles against the casing as such, but vibrates through the oil seal, then through the first shaft joint. In other words the internal shaft is the actual cause of the vibration, and the sum of the other attached parts are designed to mitigate the vibration on a standard system.

When any single part of that system is compromised from standard, the whole shift system vibrates/rattles.

The engineers even added a "shift lever damper" into the first connecting joint structure.

That said, my first joint doesnt have the play in it that NoHaveMSG has, on mine (and others I've played with) the shaft rod end moves within the seal. But it is possible that most of the boxes I've looked at are fairly low km units (mine included).

I've tried a couple of versions of the soft washer idea, and it doesnt really work too well. I've also tried the opposite idea of (very) hard packing the washers...and that didnt work either.

I also tend to agree that drilling out the entire bush on the first link (below the gear lever), and replacing it with a flexible liner of some sort might be the best option....but very difficult.

I've even considered attaching small containers 3/4 full tungsten (granules) to the main shift control shaft to see if that might dampen the vibration....

I'm gonna suggest you pull your console out and drive the car with the shifter exposed. That way you can reach through the shifter hole to feel things. Assuming you can get your hands in there.

I'm not really convinced you can replace the bushing with something soft enough to be quiet but still function properly. If you could machine an Oring groove in the bushing, that would be ideal. The Oring would prevent rattle while yielding to shifter actuation. I have my doubts that will be possible though. Have you tried wrapping the shift arm joints in something elastic that will allow them to finding, but hold them right enough to not rattle?

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[grumpysnapper]

Originally Posted by Ashikabi

I'm gonna suggest you pull your console out and drive the car with the shifter exposed. That way you can reach through the shifter hole to feel things. Assuming you can get your hands in there.

I'm not really convinced you can replace the bushing with something soft enough to be quiet but still function properly. If you could machine an Oring groove in the bushing, that would be ideal. The Oring would prevent rattle while yielding to shifter actuation. I have my doubts that will be possible though. Have you tried wrapping the shift arm joints in something elastic that will allow them to finding, but hold them right enough to not rattle?

I really like the flexible wrapping around the joints idea. I havent tried that yet.
Some sort of long silicone rubber type strip, wound around the joint(s), could potentially work quite well!

[redlined600]

Originally Posted by norcalpb

I put a plastic washer on the shifter which I believe got rid of my rattle but it would be nice to have someone else try this and report back:

I tried something similar, I bought some PTFE sheet and cut out washers to get the correct thickness. It did not work for my IRP shifter.

I'm wondering if the shifter itself isn't the issue, but rather acts as a tuning fork for whatever resonance is already present.