I have a wierd vibration, I can feel it throuout the whole car, espesially in the gearshifter, it happens when I rev the car with the clutch in, and only when the car is moving, it dosent matterwhat gear it's in. also this happen about a year ago, then I went on leave for a month, came back and it went away, I had the tranny place change the throwout bering anyways, (that's what I thought it was) and they did, they gave me the old one, and told me it looked new, and it did to me too, it rolled fine and had no play in it also, they looked at the flywheel and flexplate bolts, and they were tight. Any ideas, I don't want to pay another $200 just to change a throwout bering, that I'm not even sure is bad. My engine specs are in my sig., thanks in advance
SrA Mark D. Lewandowski, USAF

 

btt

 

So if the car is sitting still and you rev the motor with the clutch pushed in, it's OK; but if you're coasting down the road and you push the clutch in and rev it, it vibes? That makes no sense at all.

Does it vibe according to road speed, or according to engine speed?

Makes alot more sense if it doesn't do it while sitting still, but then when you're driving down the road, it does it in direct proportion to road speed. Maybe worse when you push the clutch in, maybe not.

If it's like that, it's either a U-joint; or the fit of the drive shaft slip yoke into the trans extension housing bushing, which should be tight, and gets loose from a worn bushing or yoke; or a loose pinion nut on the rear end; or bad pinion bearings (not likely).

 

it's weird if I rev it up from idel with the car just bearly moving, like 2 mph it will do it, but if the car is stoped it won't do it, also it dosen't do it when shifting gears or if I rev it up with the clutch out. It only dose it when the pedel is in, the car is roling, and you rev the engine, I'm stumped, any ideas, I seriously doubt it's in the driveline past the tranny input shaft, the viberation's harmonics varie with engine RPM, not driveline.

 

I see this is an automatic conversion; when you installed the piloit, did you use a bearing, or did you use a bushing?

 

I used a bering, from summit

 

btt

 

Why would you want to coast down the road with your clutch in, reving up your motor? I don't get it. If you don't want to feel it, don't do it!

 

I had a problem similar to that once, the faster I went the more my car vibrated (it was so bad actually I couldn't go faster than 45mph) any way as it turned out the tires were almost bald. (please don't laugh, it was my first car and I didn't know anything then)

 

it dosen't change with the speed of the veicehal, only with engine RPM, and the reason I noticed it was the engine almost died when I came to a stop, when I turned the A/C on, and I reved it to keep it going.

 

Well, with all the stuff you've got in your motor I'll bet you have been bangin' some gears pretty hard huh? If you really want to find the vibration, complete dissasembly will be required. Any mechanic will tell you that. Even hodini couldn't tell whats wrong exactly! Pull the trans and clutch and look for side to side play on your imput shaft (front bearing) if that's good I would suspect the clutch or flywheel balance. A badly worn clutch disc can have a piece of it missing and even though it seems to work ok can still cause an imbalance and in turn, vibration. You can check the pilot bearing with an old imput shaft or alignment tool. Be sure to check the flywheel bolts also, one or two may have come loose.
Same thing for the clutch plate mount bolts. How the imput shaft splines fit into the clutch disc can also create vibration. Any slop in that location will also cause vibration. I believe any standard trans. will have an acceptable amount of vibration with the clutch
in and it doesn't take much slop to increase it (from worn or mismatched parts). One thing is for sure though, over time, depending how hard you drive, it will show it's problem by coming apart in a bad way! usually at greater expence! I think I've about covered everything to look for so, the decision is yours.

 

I've had it before and found out it was the flywheel.



Scott