troubleshooting 915 rattle - wevo

[crazy997]

I have the dreaded rattle that happens at RPMs above ~4000 in 3/4 gear. When I apply gentle hand pressure to the shift lever, the rattling goes away.

My configuration:
1983 SC with WEVO classic short shifter + WEVO PSJ.

Recently installed both items NEW so lets rule that out.

I found this thread that suggested to adjust the threaded pin in the front of the shifter housing. Rattly Wevo in 915

Tried tightening and loosening the threaded pin with zero effect in either direction. Even tried adjusting this at speed with the locking nut off, no difference whatsoever.

I also tried changing the WEVO springs inside the shifter. With the softest springs, the noise still persists.

My next attempt will be to readjust the shifter coupling in hopes that will make some difference. If that fails, I may try reinstalling the stock shift coupler. I have a feeling that could resolve the issue given there is some play allowed that could lessen the vibration transmitted to the shift tube from the gearbox.

However, it seems that the majority of WEVO shifter/PSJ users have no issue so I would prefer to keep these items and resolve the underlying cause, no matter what it takes.

[crazy997]

In addition, if anyone knows of a 915 GOD in the Los Angeles area, please recommend.

[ian c2]

Tyson at pro in Burbank

[gomezoneill]

Tranny mounts or motor mounts. Or both.

[911SPete]

Try Box and Gear Transmission in Van Nuys.

[Mahler9th]

"When I apply gentle hand pressure to the shift lever, the rattling goes away."

I have been a WEVO shifter and PSJ user for about 18 years. And I know the WEVO folks. My application is a race car, so everything is noisy.

Based on the statement above, I wonder if there are opportunities with the fore/aft adjustment of your coupler. The statement above seems to imply that the nominal position of the entire mechanism, as installed/adjusted, makes or contributes to rattling noise or noises previously not experienced.

Perhaps some adjustment of the coupler can result in a nominal position that is in an acceptable range for proper shifting performance, but yields less noise.

I have experienced this when I have adjusted my shifter and coupler, which has been do many, many times since I started with the parts back in 2002 or so. When I have worked with these parts frequently, I have been able to get to my "sweet spot" with little fuss. But in more recent years, with far fewer R&R's, it has taken me a bit longer to get to my adjustment sweet sport.

And in my application, adjusting the shifter and coupler, and properly tensioning the clutch cable, are usually finalized in a track paddock. I can do an initial set of adjustments and go drive the car on the street (despite its extensive modifications), but this type of driving is never the same as rowin' thru the gears at a place like Sears Point.

[Mahler9th]

+1 on Tyson by the way. If I recall correctly he worked at Wevo for a bit, and in any case knows the cars and boxes well.

[ian c2]

Yes Tyson worked at wevo , not sure if this is one of products he worked on the development of , but either way he should be able to help .

[Mahler9th]

Pretty sure that he was there after the PSJ and shifter were already commercialized. He is very accomplished at handling set up and race driving.

[scottrx7tt]

Take the PSJ out and put the stock coupler in. Mine did the same thing. Your rattle will go away

[crazy997]

Thanks everyone for the help. I definitely feel like the solution could lie somewhere in adjusting the coupler, unfortunately I haven't had the time yet for the trial & error sessions. I have a small road trip coming up next week so I will likely throw the stock coupler back on and try again soon after.

I will contact Tyson and document the progress here.

[Flojo]

the rattling comes from spring load forcing on the gear.

many forget, that the WEVO trans improving parts is a kit of multiple components.

you actually need this as well do upgrade to a 100%

https://www.wevo.com/Products/TransmissionProducts/WevoTransmissionProducts-Internal_915Gateshift.htm

[MichaelSJackson]

crazy997,

Clearly, there are more knowledgeable members on this thread than me. But if you can use you shift lever to eliminate the noise, perhaps your coupler adjustment is off? If the shifter position is not floating in the middle of the "window" then the linkage is forcing contact. It's the reason we're not supposed to rest our hand/arm on the shifter when not actively shifting. This will result in transmission noise being transmitted along the linkage and into the cab. I assume the gateshift will prevent this? But you might be able to eliminate the noise by tuning you coupler adjustment?

I'm not trying to dissuade getting the gateshift. It's on my short list.

I've also found the Wevo coupler's precision, transmits more noise into the cab. Unfortunately in my case, I can hear the whine of bearings starting to sing.

[Dangqd]

Someone else in another thread suggested loosening the 4 bolts that hold the engine carrier to the engine cross bar, letting the car idle to reposition itself, then tighten back up. I tried this and it did significantly decrease the transmission noise through the shifting rod and shifter. I have a Wevo shifter, PSC, and close ratio 915. I had my engine out recently to replace the clutch, so loosening the engine carrier bolts and letting them settle did somehow work.

[bkreigsr]

Do you have the two rear linkage boots installed from the factory?

I replaced the firewall boot and put in the missing shirt rod boot and 90% of the linkage road noise went away.