Advice: Transmission related vibrations

[cspetros]

I'll try to make this as detailed and organized as possible. I have no experience with the transmission side of these cars, so any advice/info is appreciated. If I can add to this, let me know. The transmission is the W5M31, the car is a 1990 Galant GSX.

Essentially, my car has terrible vibrations that occur within the 2000-3000 RPM range while the clutch is engaged. It started about 5 or 6 months ago, but has recently gotten a LOT worse. It is so bad now, that the coins in my coin tray jump around. The vibration also seems to be load related, because if I'm accelerating, the vibration is much worse. It is not engine related as far as I can tell (I ruled out balance shafts when the issue first started); the vibration stops immediately whenever I disengage the clutch (pedal down).

Shifting quality has taken a nose dive. Sometimes, if I'm stopped, I have to fight the shifter to get it out of fifth gear. If the car is rolling, it's easy to take out of fifth. Shifting into first and second is much more difficult (notchy?) now than it used to be, and third gear is always crunchy now (It occasionally crunched when I first bought the car, due to worn/bad synchros).

In the last few weeks, when I disengage the clutch (pedal down, like at a stop light), a gentle metallic scrape sound comes from the transmission area (sounds similar to bad brakes). The scrape sound changes with the engine speed (slows down, speeds up), and doesn't stop until I let off the clutch pedal (engaged). The engagement point of the clutch pedal has changed from what it used to be. Now, the clutch engages almost immediately after letting up slightly on the pedal. The clutch pedal also moves slightly (1cm or less) up and down when accelerating/decelerating.

The gear shift moves about 1 or 2 cm when accelerating/decelerating in first, second, and third gear. First is the worst. It has done this since I bought the car in January. The car bucks horribly in first if I'm coasting in a parking lot, so I normally use second. A friend said this was slop in the drive line.

The car has 233,936 miles on the body. The transmission is original, and I have no records of it being serviced before, other than to change the clutch. The engine was replaced at 198,000.

I think I've written everything here. I've read every post containing the words "transmission" or "tranny" and "vibration". I've heard everything from throwout bearings to input and intermediate shafts. I'm pretty sure it's ready for a rebuild if it's not already too far gone.

This is my dd. Any advice is appreciated /ubbthreads/images/graemlins/smile.gif

 

[H05TYL]

My first guess would be that it's a clutch problem rather than a transmission problem.

It's unlikely you'll be able to rectify whatever the problem is without pulling the trans, so that would be my first move. If the clutch/flywheel and fork/pivot/release bearing all appear to be fine then step 2 would be to open up the trans and have a look.
Having said that, if you drain the trans oil and it's full of metal it's fair to assume there's a problem inside.

Unless your really lucky you probably won't be able to sort it in one weekend though.

 

[CarRacer]

Yeah it's most likely transmission related, I'm guessing intermediate shafts, but checking motor mounts wouldn't be a horrible idea before you undertake dropping the transmission. You might as well rule out the simple stuff with a visual inspection before attempting the major work.

Good luck.

 

[H05TYL]

Good point about motor mounts.

I had an intermediate shaft bearing (5th gear end) fail completely, literally nothing left by the time I'd limped it home, and no vibration at all - aside from the whining (like straight cut gears) you wouldn't've realised there was a problem! (that and the hole in the top of the gearbox) /ubbthreads/images/graemlins/dunno.gif

 

[cspetros]

Thanks for the advice guys. I guess the next step is to just pull it and see what's up. My friend has a FWD tranny that can be swapped in until we see what's going on.

Thanks again /ubbthreads/images/graemlins/smile.gif

 

+1 on the mounts.

 

[curtis]

Money says a clutch release finger is gone missing etc. Pull the dust cover deals on the bell housing on top and a bright flashlight and a mirror on a telescoping stick will prove it if it is. My buddy put a clutch in a mazda turbo other day that was only 3 weeks old and he had 5 fingers broke off and missing and was vibrating and acting like yours. Another would be to go down on Patton Ave or UNCA and find a freaky that would climb on the car and make the vibrations go away. /ubbthreads/images/graemlins/rofl.gif

 

[cspetros]

Great advice Curtis. /ubbthreads/images/graemlins/rofl.gif I'll be checking it out tomorrow. I'll update you guys as to what I find.

 

[656of1000]

If you can, you should try to drain the oil out of the trans and look for metal. This may give you a pretty good clue as to where you need to look. I'm guessing the problem may be the input shaft bearing, although I wouldn't rule out a clutch problem. I had a pressure plate finger break off a while back. It ended up swiss-cheesing my bell housing, but oddly enough, I had no vibration.

 

[cspetros]

Ok. An update to this thread. I was driving the car one day, shifted gears, and the car just stopped moving completely. Engine was running perfectly, gears shifted; the car just wouldn't move. Had it towed to my uncle's garage. I pulled the transmission yesterday. The following pictures are pretty much self explanatory:


The bolt through this hole was loose. The previous owner (who had replaced the engine) must have not torqued the bolt down to spec.


Clutch totally separated; this is why the car wouldn't move. The throwout bearing was so worn out, it fell apart into four pieces.


Pressure plate and flywheel.


This is how I secured the crank in order to remove the flywheel bolts. I didn't have any access to metal working tools to make a holder. I saw a coat hanger, and decided to try it. It worked too.

 

[GVR-4]

Nice Pics!!