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Thyperson · Posted: Tue Mar 16, 2010 1:23 pm Post subject: Vibration of satan

Hey everyone,

I took my car out for the first time since October today, ah what a great feeling, it's been sitting all winter just crying for attention. One thing that puzzled me, since I bought it, was vibration at the shifter.

I've noticed that my car decides to have this horrible vibration at 1800 RPMish whether it is driving or it is parked and rev it to that mark. It also happens when I'm on the highway sometimes, not always. So basically when I drive around town going 40-50 I want to grab the shifter and just wrench it until the clutch is no more and need to replace it (that's the satan part, see how evil it is!?!). It stops if I constantly hold the shifter down, as if shifting into the imaginary quiet gear. By "stop", I mean make it less annoying by the way, it doesn't actually stop. Releasing or pushing the accelerator doesn't help until it passes 1800 RPMish.

I'm guessing that it could possibly be tanny mounts or even a worn shifter pin (not likely). I have no idea unfortunately, those guesses came from what I got from my searching, I just got into the scene and will finally be able to actually address a bunch of issues when I move into the 2 car garage house I'll be renting starting April. So I have not been able to take anything apart and look at it yet.

I did a bunch of searches and after many hours of filtering I am kind of tired. I learned a lot about shifting problems and exhaust fumes. How I got exhaust fumes from searching anything with the word shift/er or even vibration in it I found odd, but actually answered a lot of my e-fume questions, thanks! Unfortunately, I haven't seen anything on this issue (maybe I can't read or something) or just misinterpreted some common problems. It seems like a lot of shifting problems I've read about were from certain gears or certain speeds, but not RPMs. Everything I got from reading here suggested CV joints, bushings, my 2 guesses and such, but those were for different vibration problems.

Your help is greatly appreciated and I tried to be as descriptive as possible from the driver's seat.

Thanks everyone

~Alex
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79' 924 Gorilla Mobile

Joes924Racer · Posted: Tue Mar 16, 2010 2:56 pm Post subject:

Could be a cracked tranny to torque tube coupler.. or a rear wheel bearing. Id say maybe the coupler. It happened to me they both did.. the coupler produced the same scenario you descibed.. the bearing was similiar.
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1979 porsche 924 Na
1980 porsche Turbo 931GT Replica
Have u ever driven a turbo.

fiat22turbo · Joined: 18 Jan 2006 Posts: 4040 Location: Portland, OR

Check to see if your passenger side engine mount isn't broken.

Then try to swap the axles side to side (so that the inboard joints become the outside joints). Check the wheel bearings and differential bearings while you ae at it.

While you're under the car make sure all of the nuts and bolts are properly tight, including the pinch bolts holding the transaxle to torque tube coupler in place.

Also check that the transaxle mounts are not failed and that the torque tube to transaxle bolts are tight as well.

The shift linkage bushings may be worn, exacerbating the vibration. You shouldn't really be able to hit a 1/2 gear easily.

That should give you plenty to look at for now. If you have the ability to take video and post it, we might be able to better help diagnose the problem(s)

Good luck!
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Stefan
1979 924 Carrera GTS (clone-ish)
1988 944 Turbo S (Silver Rose)

Joes924Racer · Posted: Tue Mar 16, 2010 3:24 pm Post subject:

Shift couplers break on the opposite side of the pinch bolts..
and wheel bearings go out the inner rear heel bearings.
_________________
1979 porsche 924 Na
1980 porsche Turbo 931GT Replica
Have u ever driven a turbo.

Thyperson · Posted: Wed Mar 17, 2010 10:45 am Post subject:

I realize now that I said at the end that it was a shift problem. It isn't a shift problem, it doesn't have to be in gear or even move to vibrate like that. I think I will try and make a video of this to show you guys per your request. Still drives me nuts.

Thanks for all the suggestions by the way! I will be looking into those when I get everything situated.
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79' 924 Gorilla Mobile

Lizard · Posted: Wed Mar 17, 2010 12:13 pm Post subject:

shot motor or transmission mounts will cause this.
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3 928s,

Vince Ponz · Joined: 02 Nov 2002 Posts: 3581 Location: Florida

Motor mount or shifter under the shaft is worn.
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"Never let them see you sweat"
77.5 924 modified track car
79 931 Euro stock
88 924S SE
87 911 Targa stock

Joes924Racer · Posted: Mon Mar 22, 2010 3:40 pm Post subject:

Shift coupler.
_________________
1979 porsche 924 Na
1980 porsche Turbo 931GT Replica
Have u ever driven a turbo.

Thyperson · Posted: Fri May 07, 2010 10:21 am Post subject:

Hey sorry for not posting, I have not had intronets and the move is over. I have the car on stands and will start with mounts and see if that works. I can't find my camera so I can't post a vid....sorry
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79' 924 Gorilla Mobile

Slam · Posted: Sat May 08, 2010 7:22 am Post subject:

Bad TT bearings and/or pilot bearing? Bent drive shaft?

Just off the top of my head...
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'84 944 - kid blew motor
'83 944 - resting comfortably. For 12 years
'87 944 - sideswiped by trucker
'80 924 - gone
'78 924 - gone
'77 924 - rusting comfortably