lemmiewink

hello,

I am having these wierd vibrations coming up from my 5spd shifter in certain conditions. This is an auto to 5spd swap with a custom length driveshaft due to the old one being too short.

I took off the boot so I could inspect visually what exactly is vibrating. Seems that the whole transmission is shaking. So far it only vibrates between 1500-2000 rpms and only in second gear. Above or below, there is no vibration. These vibrations are somewhat harsh and have been only happening within the past 2 weeks.

I've checked the motor and transmission mounts. They do not seem to be damaged in any way.

Also this driveshaft could not be balanced since the u joints were considered bad. They could not be replaced because they are pressed in.

But why did it decide to vibrate now instead of when I put it in initially? What else could cause this vibration? Are these vibrations dangerous or just an annoyance?

Thank you for the advice!

JspecSC3

iTrader: (4)

If it just barely began vibrating it has to be a wear and tear part. I would suspect the big rubber donut bushing that connects the end of the driveshaft to the differential. Ive seen those go bad before. Also, I would inspect the condition of the tranny mount again. Put a jack underneath it and remove the subframe mount then move the rubber mount around so you can see if it is separating. Most of the time they will look fine but the rubber will be so soft and brittle.

lemmiewink

Ok, so it is most likely the rubber parts, but what exactly am I looking for in terms of condition? There should be a little flex right?

Also, I did some experimenting. The vibration is not rpm dependant, it is speed dependant. It occurs between 15-20 mph. It just so happens that i"m in second gear whenever I am at that speed.

I've tried in first, and third and the vibration is present.

Also, as I slow down in neutral, there is vibration as I go into that range.

Hope that clears something up.

I'll check some more soon.

SHOLEXMAN

You said you changed out your driveshaft couldn't be balanced and that is a issue. Do you still have the rubber grommets on the car since you changed/modified the driveshaft? Your best bet is to take it to a driveshaft shop and have them make you a new one that is balanced out. You won't have to worry about the u joints coming apart and your driveshaft flying around. If you have the grommets on there still and there cracked try and replace them if you can. You have or can you get a pic of the driveshaft to see what your setup is? If you want another driveshaft make sure they use the correct splines and give them the measurement from your tail shaft to your connecting piece on your diff. If you feel the vibration coming from somewhere else check your tires for any bubbles cause low speeds you WILL feel it. Let me know thanks...