Carbon fiber driveshaft rs7

[Wkraus]

Has anyone done the custom aftermarket driveshaft? My rs7 is clunking. We did the srm carrier, motor mounts, trans mount and insert, bushings, sway bars etc... the driveshaft clunks if you’re counterrotate it. Something in the center. I’m told the one piece custom carbon fiber driveshafts vibrate and make noise. Anyone with any first hand experience on this? I’ve searched and searched and find nothing. Thank you!

[got_boost]

After replacing almost everything lol, it still has the clunk? For the shaft to make the noise the center slip joint or the splines at the trans would have to be really bad. I'd want to either put the car on a lift or stands and go underneath while someone else shifts from reverse/drive to maybe narrow it down? Unless you need to be moving for the clunk to happen?

As far as a CF shaft making noise/vibrating, I don't have any first hand knowledge. Not sure how they could balance a fiber shaft? Glueing weights? But if it's not balanced properly I could see it causing a hum.

[Wkraus]

After replacing almost everything lol, it still has the clunk? For the shaft to make the noise the center slip joint or the splines at the trans would have to be really bad. I'd want to either put the car on a lift or stands and go underneath while someone else shifts from reverse/drive to maybe narrow it down? Unless you need to be moving for the clunk to happen?

As far as a CF shaft making noise/vibrating, I don't have any first hand knowledge. Not sure how they could balance a fiber shaft? Glueing weights? But if it's not balanced properly I could see it causing a hum.

Thank you for the reply! Yes we have actually narrowed it down it is definitely coming from the center of the driveshaft. We had it up on the hoist and going back-and-forth between reverse and drive and so we decided to just each grab an end and counter rotate and sure enough it clunks in the center of the driveshaft

[got_boost]

Wow, this would be interesting to see first hand. So I guess you only have 2 options then, go aftermarket shaft which might need to be custom made? unless someone makes one already or go back with OEM and roll the dice that maybe your current shaft was defective.

[Wkraus]

Wow, this would be interesting to see first hand. So I guess you only have 2 options then, go aftermarket shaft which might need to be custom made? unless someone makes one already or go back with OEM and roll the dice that maybe your current shaft was defective.

Still having the issue. My mechanic had another rs7 in the shop and he said that car had no play like mine does at the trans. Anyone have any idea what would allow the output of the trans where it bolts in to the. driveshaft to have some slop in it? How would one get an exploded view or find out what would allow some slop at that area? Same as the differential input?

[Wkraus]

I should have named the thread clunking drivetrain!

[got_boost]

Just out of curiosity, did you buy it new or were there previous owners? If it was prev owned, is it possible the noise was there when you go it? The only other think I am think of is maybe,not sure how far fetched it may be, but maybe a wrong shaft was put in? If possible maybe spin the shaft and see if there is still an oe part sticker with a part # where you could look it up and make sure it's an rs7 shaft?
I could be hoping for something crazy but there are crazy people out there and will use what use what ever might work.

It may be more work than it's worth, but maybe pull the shaft and measure the splines and see if it's an issue if different size splines causing the slop or if they are the same then maybe it's internal issue of the trans but I'd hope that's not the case. Again that's if the noise is def coming from the front half of the shaft.

[mpk1996]

Still having the issue. My mechanic had another rs7 in the shop and he said that car had no play like mine does at the trans. Anyone have any idea what would allow the output of the trans where it bolts in to the. driveshaft to have some slop in it? How would one get an exploded view or find out what would allow some slop at that area? Same as the differential input?

not to be captain obvious, but you say the slop is up by the transmission. is stop coming from the transmission or the drive shaft? you should be able to grab different parts of the drive shaft forward and aft of each joint to see what joint has play. is it possible to have slop in the trans itself?

[Wkraus]

not to be captain obvious, but you say the slop is up by the transmission. is stop coming from the transmission or the drive shaft? you should be able to grab different parts of the drive shaft forward and aft of each joint to see what joint has play. is it possible to have slop in the trans itself?

We’ve actually done both. We can see the end of the trans where the driveshaft bolts up moves about half inch either way if I recall, and if we two hand the driveshaft it has play also. I did buy the car used but it was completely stock and owned by an older family. In Canada. It has a metal tink sound when going from drive to reverse or vise versa and a clunk. It seems to be worse warmed up if that makes any sense. I’ll try and get a video of it and post to YouTube and paste a link next time I drive it. I am ultra fussy and silly stuff like this bother me a lot. It makes me not like the car at all.

[mpk1996]

We’ve actually done both. We can see the end of the trans where the driveshaft bolts up moves about half inch either way if I recall, and if we two hand the driveshaft it has play also. I did buy the car used but it was completely stock and owned by an older family. In Canada. It has a metal tink sound when going from drive to reverse or vise versa and a clunk. It seems to be worse warmed up if that makes any sense. I’ll try and get a video of it and post to YouTube and paste a link next time I drive it. I am ultra fussy and silly stuff like this bother me a lot. It makes me not like the car at all.

ok. if the noise is not coming from the U joint in the two piece driveshaft or play in the carrier support, i would not think that going to a 1 piece is going to fix your problem. you have excessive lash in either the trans or the rear diff causing the noise. so, if you grab the driveshaft (one hand on one side of the U joint, one hand on the other) and twist in opposite directions and nothing happens, its not your driveshaft itself. i suppose it could be your yoke with some slop on the transmission shaft, again, thats more unlikely than just excess lash in the rear

[Wkraus]

ok. if the noise is not coming from the U joint in the two piece driveshaft or play in the carrier support, i would not think that going to a 1 piece is going to fix your problem. you have excessive lash in either the trans or the rear diff causing the noise. so, if you grab the driveshaft (one hand on one side of the U joint, one hand on the other) and twist in opposite directions and nothing happens, its not your driveshaft itself. i suppose it could be your yoke with some slop on the transmission shaft, again, thats more unlikely than just excess lash in the rear

It definitely has some play with the driveshaft when we do that, but we also have a little play at both the rear end and the transmission. I’m wondering what is inside the end of the transmission that could get sloppy and what it’s going to cost to get rid of the clink sound. Any update on your car? I’ll try and get a video when i drive it again and text you!

[Wkraus]

Ok here are a couple videos that don’t really do a good job of letting you feel and hear what I do while in the car but it’s what I have from last week to show.

https://youtu.be/Zrptt9aHRIY

https://youtu.be/bedZEtkUYQM

[mpk1996]

Ok here are a couple videos that don’t really do a good job of letting you feel and hear what I do while in the car but it’s what I have from last week to show.

https://youtu.be/Zrptt9aHRIY

https://youtu.be/bedZEtkUYQM

wow. you can def here that. i'm assuming from the second video that the clunk coming in the first is when you are shifting from D to R? honestly it just seems like excessive lash to me. do it do that when you are driving and on and off the gas pedal? so a coast to acceleration? like go down the road in M in 3rd at 30-35 mph and find that spot where when you lift just a little you coast/eng brake then on the gas you are driving it forward. if it does it then, i would suspect the rear diff (the trans would be all "locked" up then, not sure if the converter in those is a locking/unlocking type though). if it only does it like you are showing in going from R to D, then maybe something in the trans swapping between the drive side and the rev side.

[Wkraus]

wow. you can def here that. i'm assuming from the second video that the clunk coming in the first is when you are shifting from D to R? honestly it just seems like excessive lash to me. do it do that when you are driving and on and off the gas pedal? so a coast to acceleration? like go down the road in M in 3rd at 30-35 mph and find that spot where when you lift just a little you coast/eng brake then on the gas you are driving it forward. if it does it then, i would suspect the rear diff (the trans would be all "locked" up then, not sure if the converter in those is a locking/unlocking type though). if it only does it like you are showing in going from R to D, then maybe something in the trans swapping between the drive side and the rev side.

Unfortunately it does it going down the highway and it has a little bit of a howl. I think this might’ve started after i broke an axle. I wish I could see an exploded view of these areas somewhere. I am going to ask my mechanic if he can find something to show it.

[mpk1996]

Unfortunately it does it going down the highway and it has a little bit of a howl. I think this might’ve started after i broke an axle. I wish I could see an exploded view of these areas somewhere. I am going to ask my mechanic if he can find something to show it.

ok. that is def lash in your rear differential. i had a car that had the rear howling as well. the rear was not set up right. since you had something rebuilt there, i would start there and not the driveshaft

[Alabama]

I think this might’ve started after i broke an axle.

Did the axle break before last September?

[Wkraus]

Did the axle break before last September?
June of 2019. HereÂ’s the video. IÂ’ve always wondered what else let go. You can hear 2 breaks. Custom code was my tuner at the time and I was on the phone with him after it broke. He said it was either a driveshaft or the torque converter let go. He said there was bolts that shear if I recall? I really feel something in the end of the trans is sloppy. The rear end has a little bit. IÂ’ll see about getting it on a hoist and take some more videos. I truly appreciate all the information guys, it usually saves me a ton of money from all your collective experience on these issues! Thanks again!!

https://youtu.be/xfCEv0bRtC4

[Euconect]

Im experiencing same clunking after SRM TCU flash and support bearing install. Happens every time i press gass and on every downshift. Its driving me crazy.