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Wobble/shake at around 3400 rpm

V

vertebrate

New member
I just got done replacing a *very* worn engine mount today. While it made some horrendous vibrations that came around 1500rpm go away, I now have a situation where around 3000-3500rpm(3400 is the most violent) there is a significant wobbling/shaking. I checked the lug nuts, and they are secured properly. I honestly can't remember if this wobbling was there before the mount change. I don't believe it was. It only happens when in gear. In park or neutral there are no problems. Any idea what this could be, or at least where I could start looking?

Thanks,
Steve
2000 Grand Prix GTP
 


did you secure the bolts for the motor mount???

if you changed it and there wasent a problem before then it is probably something you did ex. motor mount
 
Did you change the trans mount. It may not have been as bad as the motor mount, but now that that is fixed, it could be showing up now.
 
did you check the height dif between the new/old mount?

does it change depending on how your wheels are turned?
 
Sorry for not replying sooner, I didn't have mail notifications on, and forgot about the thread. It turns out it's not related necessarily to engine rpm. It's more a 35-45mph thing, pretty much on acceleration up to and through that point. If I let off the accelerator the problem goes away.

I did find that my outer tie rod ends are hosed, and have some play in them. I'm currently working on replacing those, but holy crap the jam nut is stuck on something fierce. I have pb blasted, torched, hammered. I cannot get the thing off. I'm starting to think that it's welded on!

I'll have to check the trans mount, and the height difference if I ever get these rod ends done.
 


well most likely axle or tire related for that vibration.
its possible you damaged the axle during the mount install. it can happen pretty easily.
 
I was pretty careful with them during the install. Is there any way to confirm for sure that they're damaged? The reason I'm looking at the tie rod ends(gave up last night, will try again today) is that the driver side actually has play in it, which I'm thinking could be causing the wobble or vibration.
 
I know this is a way old thread but did you ever figure this out? I'm having the same problem. I get this weird shake that only shows up between 35 and 45 MPH and only while the gas pedal is pressed. The harder the gas is pressed, the harder the shaking. I've replaced the lower motor mount, tie rod ends, rack and pinion, control arms, bushings, ball joints, struts, strut mounts, had tires balanced, tried swapping tires, and had an alignment. Any other ideas?
 
Oops. I forgot to mention I have replaced the driver axle. I knew it was bad because all the grease leaked out of the inner boot. I thought for sure that would fix it and it had no affect. I have 162K on the clock and my pass. axle is still the factory one. The boots are crack/tear free and when I changed the oil last night I tried to wiggle the axle to see if there was play and it seemed rock solid. Should I just replace it on faith? lol
 


im having that same wobble. only its around 70 mph. especially when on the gas. I changed the passenger drive axel. however i cant change the driver one because there was a nub sticking out of my transmission when i removed the old one. Does anyone know what that splined nub is all about? like the drive shaft came off female and there was a splined male protrustion. I dont know if my driveshaft came apart or if that is normal on an 01.. sorry to thread jack.
 


hey matt i changed out the wheel bearings and the finally learned how to do tie rods on the bonne last night but when u get the axle i wanna come over and watch u so i can learn
 
No problem. I'm picking up a ball joint tool tonight and the axle should be here tomorrow. So I'll probably put the axle in Friday night.
 
Well, for anyone interested the passenger axle was the problem. Got the new one in last night and no more shaking! It wasn't too bad a job, but WAY more tranny fluid leaked out than I thought would.
When I took the old axle out there was hardly any play in the joints, but there was some. I guess it only takes a tiny bit to cause a big problem. So hopefully if anyone else runs into the same problem this gives them a head start! :)
 
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