Driveline Vibration Elimination Desired

**Bitsa** · 07-04-2012, 03:04 PM

Been a while since I posted here. Long sad story. Anyway, I've a vibration in my rt142 wagon that is driving me nuts. It seems to be in the driveline. It occurs at differing times i.e. there's a slight vibration that starts in 2nd until you get to 60k's in 4th. Cruising at 60k's no vibration. If I back off in 4th at 60k's there's a bit of a vibration. If I'm doing 60k's in 3rd however and back off the car vibrates violently.

If you floor it through the gears or just take off a little bit quicker no vibration is felt.

Cruising at 100k's or thereabouts in 5th gear then taking my foot off the accelerator to slow down it will start to vibrate slightly at around 80k's. If you change into 4th at this time the vibration gets a little bit vibratier. If you then change into 3rd it feels like the whole car is going to vibrate to pieces.

Thing is, if I feather the accelerator or depress the clutch as this time the vibration stops instantly. There's got to be something in this but I've no idea what.

So far I have eliminated the wheels and tyres (all good), tailshaft (had a new 1 piece made) rear axles and bearings, engine mounts, gearbox mount, exhaust. I put another diff in it, but, the amount of play in the diff (pinion?) where the tailshaft meets the diff is quite a lot. Not sure if that's good or bad. Apart from the pinion (?) movement, I've pretty much eliminated everything from the tailshaft back or is there something I've missed ?

What I'd like to know is whether the gearbox or clutch or flywheel can cause the car to do what it's doing. I've got no idea really.

The feathering of the accelerator or depressing the clutch to stop the vibration surely must be a sign of something ?

Any help appreciated,

Trevor

**oldcorollas** · 07-04-2012, 03:14 PM

i'd be aiming to reduce pinion backlash.

busted friction plate in the clutch can cause issues also

**Celica RA45** · 07-04-2012, 06:02 PM

look at the pressure plate might have broken strap

**ToyTA22** · 07-04-2012, 06:22 PM

I'm with oldcorollas and CelicaRA45. Remove clutch and check clutch plate and pressure plate aligned properly. I have had a car which someone prior put small washer on alignment pin before bolting clutch together and did simillar thing after a while, due to broken clutch plate.

**George** · 07-04-2012, 06:25 PM

I'd vote for clutch problem, too. But it may be not the only one
In particular, playing with accelerator around 80k's points to somewhere around tailshaft. It may be balanced but not centered properly. And make sure there's no radial play on either end of it. That is, when under the car, try pushing it up and down, shaft should not move.

You can arrange some simple test. Put rear axle to some bricks so wheels would spin freely but suspension would be in its normal position. Set your speed/rev of problem, then with some luck you can observe the vibration, or make a guess about its source touching different driveline parts

**Bitsa** · 07-04-2012, 06:42 PM

.......i'd be aiming to reduce pinion backlash.......

That sounds like a good idea. Am I going have to take it to diff man to get it somewhere near right or is that something I can do myself ? Haven't done it before. Actually, how hard is it to get out ?

........busted friction plate in the clutch can cause issues also.........look at the pressure plate might have broken strap........I'm with oldcorollas and CelicaRA45. Remove clutch and check clutch plate and pressure plate aligned properly. I have had a car which someone prior put small washer on alignment pin before bolting clutch together and did simillar thing after a while, due to broken clutch plate......

Booooooooooo but Ok. The clutch was replaced about 5 years ago. Have done a lot of k's since then so time to replace it again by the sounds of it.

Thanks for the replies men. Appreciated.

**Bitsa** · 07-04-2012, 06:50 PM

Originally Posted by George

I'd vote for clutch problem, too. But it may be not the only one
In particular, playing with accelerator around 80k's points to somewhere around tailshaft. It may be balanced but not centered properly. And make sure there's no radial play on either end of it. That is, when under the car, try pushing it up and down, shaft should not move.

You can arrange some simple test. Put rear axle to some bricks so wheels would spin freely but suspension would be in its normal position. Set your speed/rev of problem, then with some luck you can observe the vibration, or make a guess about its source touching different driveline parts

Thanks George. I'll get under it tommorrow and check that out, again. I say again because I've already done something similiar and when i did it the diff area made a horrible grinding type noise when i put the car in 3rd gear. I'd forgotten about that.