adawang

I measured my pinion angle(rear axle differential angle) Evo 9 wagon auto.
>3 degrees, nose up towards the rear , positive pinion angle
transmission output shaft < 1 degree , nose down towards the rear
Is it out of spec? chasing driveline vibrations for quite a while and appreciate your assistance.

barneyb

Are the u-joints 90 degrees out of phase?

adawang

I bought the complete unit propeller shaft from Japan stockist and the workshop removed the old and fitted the new. "plug and play"
The shaft came in complete assembled and we didn't take apart the sections.
Didnt solve the vibration.
U mean to take apart the shaft, rotate 90 degrees and installed it back?

barneyb

No, I thought if it had been worked on my a local shop it might have been misassembled.

I had to replace the propeller shaft on my car this last summer and it came the same way - long box - but I didn't have any vibration problems.

adawang

Thanks. the prop shaft is ruled out
The next thing I have to check is the pinion angle and the transmission output angle.
Read from the net saying the pinion and transmission output angles have be equal.

LetsGetThisDone

iTrader: (1)

The driveshaft has a lobro/cv joint in it. Angle of rear diff input vs tcase output doesn't matter.

barneyb

When bent u-joints don't turn with constant velocity - hence the CV joints like in our front axles with different designs. As the u-joint angle increases the unevenness of the rotation increases. I remember in old Chevys how they would angle both the transmission and rear differential down to decrease the hump needed in the cabin floor. You had to keep the angle within certain limits or feel a vibration and there was a tool for measuring this. With two u-joints in the Evo propeller shaft I don't think the lobro joint is a cure if the u-joints are causing a vibration.

Anyway, the angles the OP is measuring are pretty small. Anything in the drivetrain out of balance could be causing the problem.

adawang

The workshop thinks it is the auto trans valve body that causing the vibrations but
I do not think so.
The feeling at slow speed is like a slight wobbly kind of feeling and not exactly up and down vibrations

barneyb

Could be an axle.

adawang

These are suspects
1)valve body ????
2)axles front / rear??
3)angle between transmission output shaft and rear differential - may not be.

Believe the vibration,/wobbly feeling is causing uneven tyre wear. Michelin Premacy tyres were fitted new in Dec 2017
Now, the tyres has a slight 1 .5 mm lateral groove motion when spun on hoist.and out of round symptoms within 3 months of use.
I'm into the second set of Premacy tyres since with this issue.

what was replaced, after running over a piece of wood on the road
2 damaged dented rims - front left and rear right replaced
2 punctured tyres replaced with set of 4 Goodyear
front and rear shocks replaced
4 sets of wheel bearing assembly replaced
front drive shaft left and right replaced
rear left right drive shaft cheked and serviced
front left knuckle replaced
whole propeller shaft assembly
steering rack and pinion serviced
left and right rear lower arm replaced with Megan Racing
replaced with set of 4 Michelin Premacy

Need advice, what else could I have missed?

Would it be possible to remove the propeller shaft , test drive basis front wheel drive to rule out the possibility of driveline angles, chassis ?

Many thanks & looking to resolve the wobbly vibration issue.