Weird mostly speed-based vibration i cannot brain
#21
Update: Driveshaft looks fine. Smooth movement in all directions at U Joints, no play that i can feel, and i sat there for 10 minutes trying to find some.
Because.... all i can think at this point is the transmission. I've since noticed that while it seems to vibrate at 70mph+ in any gear, it will also start to vibrate at 40mph in 4th and 6th gear specifically. Nowhere near the intensity that it does at 70mph+, but it's definitely there. 5th gear at 40mph is silky smooth.
Busticated transmission seem likely to anyone else?
I have to get under the car again after work to put the driveshaft and midpipe back up, i'll check the PPF angle for the 37th time.
Because.... all i can think at this point is the transmission. I've since noticed that while it seems to vibrate at 70mph+ in any gear, it will also start to vibrate at 40mph in 4th and 6th gear specifically. Nowhere near the intensity that it does at 70mph+, but it's definitely there. 5th gear at 40mph is silky smooth.
Busticated transmission seem likely to anyone else?
I have to get under the car again after work to put the driveshaft and midpipe back up, i'll check the PPF angle for the 37th time.
#23
Will do.
Do my symptoms point to transmission like my pea brain thinks it does, otherwise?
Trans had a fairly major leak from neutral sensor, likely for awhile. I have no doubts it was run quite low on fluid. Shifts good though and doesn't seem excessively noisy, which is why I didn't originally go straight to that.
Do my symptoms point to transmission like my pea brain thinks it does, otherwise?
Trans had a fairly major leak from neutral sensor, likely for awhile. I have no doubts it was run quite low on fluid. Shifts good though and doesn't seem excessively noisy, which is why I didn't originally go straight to that.
#24
Driveshaft Balance?
I had a very similar problem; although, mine was not dependent at all on gearing. Nearing 70 MPH I would get an increasing vibration that seemed to come from the rear of the vehicle, and it would increase dramatically as I increased in speed beyond 70. After trying numerous solutions, I took my driveshaft in to be re-balanced and that solved it. I'm not sure how my driveshaft became out of balance but there were no obvious signs of damage to it. It was only about a 3-year old driveshaft with probably 15K miles on it, but I have taken it out of the vehicle several times and may have knocked out of balance in the process.
Bryan
Bryan
#30
Cpt. Slow
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Did you ever solve this? Deviett is having a similar problem. Blackbird drop mounts, poly diff, 6-speed, new driveshaft, 70mph and gets worse with speed. I’ll do a ppf alignment, but I’m wondering what your solution was.
#31
Tested by jacking the rear of the car up, removing the wheels, and running the car up to speed in the air. Noticeable vibration by 60mph, gets really bad once I hit 80.
#32
Cpt. Slow
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I wonder if the drop mounts require a different alignment. You might tru loosening all three front ppf bolts and letting it drop all the way and trying again. Or let AR do it, I hate having you waste time on this. We still have another driveshaft to try as well.
#35
I have another set of motor mounts and a complete set of loaded uprights with SadFAB sphericals in the rear uprights to slam into it when i get a chance, but cars aren't real important to me at the moment. If the uprights don't fix it, i have to move on to checking stupid crap like brake rotors and wheels. I do have one wheel/tire set that we couldn't get under 12lbs of road force , the other three got down to 7lbs. Unfortunately i didn't mark which one that was, nor am i sure if the car is THAT sensitive, 12lbs isn't much. (I'll be pretty salty if my brand new Hypergrams are the cause of this entire thing, though.)
#36
Nope. I've had 3 sets of motor mounts in the car, currently on AWR 70 not-drop mounts. I've swapped trans, diff, driveshaft, and i've aligned the PPF a dozen or so times. It's as perfect as it gets. It's a bit mind-boggling in general. The car, mechanically-speaking, is one of the most perfect things i've ever owned.
I have another set of motor mounts and a complete set of loaded uprights with SadFAB sphericals in the rear uprights to slam into it when i get a chance, but cars aren't real important to me at the moment. If the uprights don't fix it, i have to move on to checking stupid crap like brake rotors and wheels. I do have one wheel/tire set that we couldn't get under 12lbs of road force , the other three got down to 7lbs. Unfortunately i didn't mark which one that was, nor am i sure if the car is THAT sensitive, 12lbs isn't much. (I'll be pretty salty if my brand new Hypergrams are the cause of this entire thing, though.)
I have another set of motor mounts and a complete set of loaded uprights with SadFAB sphericals in the rear uprights to slam into it when i get a chance, but cars aren't real important to me at the moment. If the uprights don't fix it, i have to move on to checking stupid crap like brake rotors and wheels. I do have one wheel/tire set that we couldn't get under 12lbs of road force , the other three got down to 7lbs. Unfortunately i didn't mark which one that was, nor am i sure if the car is THAT sensitive, 12lbs isn't much. (I'll be pretty salty if my brand new Hypergrams are the cause of this entire thing, though.)
#37
Well that isn't encouraging. Sounds like you had a lot more variables going on though, only changes in my setup were the driveshaft and potentially PPF alignment. Other than all the turbo bits, but I wouldn't think that would cause this since it is unrelated to engine speed.
#38
Well.... all those things were changed in search of a solution to the vibration. It was present prior. It's a bit frustrating, there's cubic dollars in this car, and not a single knockoff/cheap part on it, anywhere. I easily took the crown away from you for "most expensive 140hp car."
Prior to the most recent work I only had vibration approaching 100mph. What I'm feeling at 60 now is worse than what I had at 100 before, so if I could just get back to the way things were that would be a major improvement.