jcslocum

1986 944 N/A 120K miles.

We have a vibration in the shifter that starts at about 3500 RPM and gets worse by 4000 RPM. I think you can hear it but it's mostly in the shifter. Any idea what this is caused by??

There are no other noises or issues that we are hearing/feeling.

CyCloNe!

Torque Tube bearings most likely.. check the coupler by the trans make sure its on tight, engine/trans mounts, and tighten and inspect linkage on shifter.

zedsn

Did you recently purchase the car or did this just start to happen? When I bought my 83 na I had a vibration at that rpm. Turns out my balance shafts were off by a tooth. The prior owner had a broken timing belt and had someone repair the car. My timing belt was also off a tooth.

jcslocum

I think it was always there but my daughter uses it at school so I don't drive it much. We bought it last summer and installed all new belts, water pump etc....

I will check the balance shafts.

pnbell

My car has a similiar issue. Probably just worn bushings in the Shifter Assembly.

There are a several Rubber parts which help mute the vibrations caused by the extremely long shifter linkage; they get hard over time and stop being effective... I would worry about it too much, plus it's a nice reminder not to rest your hand on the shifter while driving, Ha HA!

Hmmmm, Your Daughter Drives an 80's 5-speed sports car? I'm a single guy in his 20's!

*just don't tell my girlfriend i said that.... :/

JohnKoaWood

Hell for that matter, I'm a soon to be single, business owner in his mid 30s..

And I do have a certain weakness for mid 80s sports cars...

JohnKoaWood

TT bearings whine.

Coupler doesn't throw RPM specific vibes.

Engine trans mounts are noticeable at IDLE.

Linkage on shift causes sloppiness not vibration.

RPM specific vibration is Balance shaft alignment, 4K RPM, check the alignment of the lower BS, set the crank to TDC #1 and verify the notches in each BS are aligned with the marks on the belt covers (and that the cam is on its timing mark, look through he hole in the front of the cam belt cover on the front of the cam tower).

I am willing to bet at least one of the balance shafts is off!

Supporting this would be if the vibration is engine RPM specific regardless of gear the car is in. (Including in gear, with clutch pedal pushed in)

jcslocum

Yup, She's a good wrench, can weld. loves cars, rides a motorcycle and is studying for her masters in psychology. Pretty too!

Here she is admiring her welds when she replaced the broken CatCon 4 weeks ago. She does 90% of her own work. She also put a turbo nose on her 944. Likes it better than the stock look.