Shake/Shudder above 60MPH
Thread Starter
Racer
Joined: Mar 2015
Posts: 412
Likes: 284
From: Indianapolis
Shake/Shudder above 60MPH
Well continuing the saga of random issues with my C5... it has developed a shudder above 60MPH when on throttle. It is throughout the entire chassis, though I can particularly feel it in the shifter and through the driveline. If I let off the throttle or throw it into neutral the shake in the shifter is gone, though there's still some vibration in the chassis.
I had all 4 wheels rebalanced as I figured it was the easiest variable to eliminate. Shop said they were off by a hair but not enough to cause what I'm talking about. Some guys I spoke with think it's the TT couplers, which given that it goes away if I'm off the throttle/put it into neutral isn't outside the realm of possibility, but I would have expected to feel it across certain RPM ranges, not above certain speeds.
I'm at a loss though, barring either some really bad wheel bearings or a half-shaft that somehow got way out of balance I can't imagine anything else causing this. Any ideas before I yank the TT out (again)?
I had all 4 wheels rebalanced as I figured it was the easiest variable to eliminate. Shop said they were off by a hair but not enough to cause what I'm talking about. Some guys I spoke with think it's the TT couplers, which given that it goes away if I'm off the throttle/put it into neutral isn't outside the realm of possibility, but I would have expected to feel it across certain RPM ranges, not above certain speeds.
I'm at a loss though, barring either some really bad wheel bearings or a half-shaft that somehow got way out of balance I can't imagine anything else causing this. Any ideas before I yank the TT out (again)?
Tech Contributor
Joined: Jan 2007
Posts: 19,398
Likes: 1,139
From: Dyer, IN
At least tell the whole story. This is not just a random event that happened to your daily driver. This is salvage car with major suspension damaged that you have pieced together.
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https://www.corvetteforum.com/forums...n-project.html
Thread Starter
Racer
Joined: Mar 2015
Posts: 412
Likes: 284
From: Indianapolis
So an update.
Some people on FB suggested that it was an issue with the TT and/or the couplers. Just pulled it and I see no glaringly obvious issues there. Barring the driveshaft somehow bending or somehow magically becoming unbalanced I don't think that's the cause. Going to have the shaft balanced anyway just for peace of mind (might replace the couplers as well since it's apart).
Once I get it back together, I'm going to throw a buddy's set of wheels on the car just to eliminate the wheels as a possibility in their entirety. Only thing of note is that the rear drivers side wheel has a fair bit more weight on it than the rest of the wheels (4.25oz vs the rest at 1-2oz) but not a crazy amount.
The issue does happen in all gears so I don't think it's the transmission. Barring some weird issue with the diff I'm at a loss.
Some people on FB suggested that it was an issue with the TT and/or the couplers. Just pulled it and I see no glaringly obvious issues there. Barring the driveshaft somehow bending or somehow magically becoming unbalanced I don't think that's the cause. Going to have the shaft balanced anyway just for peace of mind (might replace the couplers as well since it's apart).
Once I get it back together, I'm going to throw a buddy's set of wheels on the car just to eliminate the wheels as a possibility in their entirety. Only thing of note is that the rear drivers side wheel has a fair bit more weight on it than the rest of the wheels (4.25oz vs the rest at 1-2oz) but not a crazy amount.
The issue does happen in all gears so I don't think it's the transmission. Barring some weird issue with the diff I'm at a loss.
Thread Starter
Racer
Joined: Mar 2015
Posts: 412
Likes: 284
From: Indianapolis
Another update.
I didn't want to post until I had confirmed the fix. When I pulled the TT apart and did the couplers, I decided I was going to have the DS balanced, just as a CYA thing. Turns out it's a good thing I did, as the shop I took it to said the DS was bent pretty badly. They were able to straighten it out and rebalance it however. After some futzing with my clutch speed bleeder (I have become a master at stabbing the TT in now) I took it for a test drive yesterday. Vibration appears to be gone! Held it at 61 (where it was at its worst) and nothing but smooth sailing.
The real question is, how tf did the DS get bent? I had the shop check the TT just in case and they said it was spot on.
I didn't want to post until I had confirmed the fix. When I pulled the TT apart and did the couplers, I decided I was going to have the DS balanced, just as a CYA thing. Turns out it's a good thing I did, as the shop I took it to said the DS was bent pretty badly. They were able to straighten it out and rebalance it however. After some futzing with my clutch speed bleeder (I have become a master at stabbing the TT in now) I took it for a test drive yesterday. Vibration appears to be gone! Held it at 61 (where it was at its worst) and nothing but smooth sailing.
The real question is, how tf did the DS get bent? I had the shop check the TT just in case and they said it was spot on.
Burning Brakes
Joined: Jun 2007
Posts: 772
Likes: 213
From: Auburn Ohio
Another update.
I didn't want to post until I had confirmed the fix. When I pulled the TT apart and did the couplers, I decided I was going to have the DS balanced, just as a CYA thing. Turns out it's a good thing I did, as the shop I took it to said the DS was bent pretty badly. They were able to straighten it out and rebalance it however. After some futzing with my clutch speed bleeder (I have become a master at stabbing the TT in now) I took it for a test drive yesterday. Vibration appears to be gone! Held it at 61 (where it was at its worst) and nothing but smooth sailing.
The real question is, how tf did the DS get bent? I had the shop check the TT just in case and they said it was spot on.
I didn't want to post until I had confirmed the fix. When I pulled the TT apart and did the couplers, I decided I was going to have the DS balanced, just as a CYA thing. Turns out it's a good thing I did, as the shop I took it to said the DS was bent pretty badly. They were able to straighten it out and rebalance it however. After some futzing with my clutch speed bleeder (I have become a master at stabbing the TT in now) I took it for a test drive yesterday. Vibration appears to be gone! Held it at 61 (where it was at its worst) and nothing but smooth sailing.
The real question is, how tf did the DS get bent? I had the shop check the TT just in case and they said it was spot on.
Not tire balance
Not anything obvious. Just the under load mild but annoying shudder
No load ....goes away
Thanks for Posting
Advanced
Joined: Oct 2025
Posts: 64
Likes: 72
From: Pleasanton, CA
My 2016 with 33k miles had a shudder on light acceleration about 60mph and it turned out to be the transmission. It felt like I was driving over a wash board. We did the GM TSB triple flush and it seems to have fixed the problem. Not cheap at the dealership but I was glad it solved the problem.
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Drifting
Joined: Jul 2004
Posts: 1,659
Likes: 683
From: Pingree Grove IL
My 2016 with 33k miles had a shudder on light acceleration about 60mph and it turned out to be the transmission. It felt like I was driving over a wash board. We did the GM TSB triple flush and it seems to have fixed the problem. Not cheap at the dealership but I was glad it solved the problem.
That’s a C7 thingy, your in the C5 section. And, IMO, the triple flush is a band aide. Your problem is still there. There are some write ups out there on this. Good luck with your C7. Here’s what I heard from a transmission guy. The AFM or DOD, whatever it’s called, puts pressure on the cheap torque converters, torque converter breaks overtime, pieces fly into the transmission and now it’s broke. You need to have the cam and lifters replaced, get the DOD or AFM tuned out, get a Yank converter, then hopefully the transmission will be okay after that.
Advanced
Joined: Oct 2025
Posts: 64
Likes: 72
From: Pleasanton, CA
.
That’s a C7 thingy, your in the C5 section. And, IMO, the triple flush is a band aide. Your problem is still there. There are some write ups out there on this. Good luck with your C7. Here’s what I heard from a transmission guy. The AFM or DOD, whatever it’s called, puts pressure on the cheap torque converters, torque converter breaks overtime, pieces fly into the transmission and now it’s broke. You need to have the cam and lifters replaced, get the DOD or AFM tuned out, get a Yank converter, then hopefully the transmission will be okay after that.
That’s a C7 thingy, your in the C5 section. And, IMO, the triple flush is a band aide. Your problem is still there. There are some write ups out there on this. Good luck with your C7. Here’s what I heard from a transmission guy. The AFM or DOD, whatever it’s called, puts pressure on the cheap torque converters, torque converter breaks overtime, pieces fly into the transmission and now it’s broke. You need to have the cam and lifters replaced, get the DOD or AFM tuned out, get a Yank converter, then hopefully the transmission will be okay after that.