Yoke play / Vibration

latil · Post by **latil** » Mon Oct 27, 14 8:03 am

Do you get any vibration out of gear,up through the rev range? Bent half shaft/out of true wheel/brake drum could be other causes if only happening when it's in gear.

db · Post by db » Mon Oct 27, 14 9:00 am

Does it still vibrate in neutral?

Philth · Post by **Philth** » Mon Oct 27, 14 5:21 pm

Check the angle of the output shaft of the gearbox to the input shaft of the differential. What you describe sounds like the nose of the diff is potentially pointing too high or low. Same can also happen with very saggy transmission mounts, making the transmission point too low.

I have the adjustable front spring hanger mounts on my car and in the higher position caused a similar vibration as you have described. I swapped it back to the lower position and the vibration went (note: the adjustable hanger mounts should be used with angled shim plates under the spring perches).

Some descriptions here: -
http://www.hotrodhotline.com/md/html/dr ... monics.php

Loads of other info out there....(yup - I looked it up too when I was flummoxed!).

sinny · Post by **sinny** » Mon Oct 27, 14 7:14 pm

Not sure if it does it in neutral so will check.

I'll take a look at the prop angle.

Mossy68 · Post by **Mossy68** » Mon Oct 27, 14 7:47 pm

Shaun. Have you tried it in a couple of gears ?
I.e bring it up to the vibration in second. Note speed. Then match speed in third. If it still vibrates at the same speed regardless of gear then it's not your driveshaft. ?

Worn UJ bearings ????

db · Post by db » Mon Oct 27, 14 8:03 pm

Philth wrote:Check the angle of the output shaft of the gearbox to the input shaft of the differential. What you describe sounds like the nose of the diff is potentially pointing too high or low. Same can also happen with very saggy transmission mounts, making the transmission point too low.

I have the adjustable front spring hanger mounts on my car and in the higher position caused a similar vibration as you have described. I swapped it back to the lower position and the vibration went (note: the adjustable hanger mounts should be used with angled shim plates under the spring perches).

Some descriptions here: -
http://www.hotrodhotline.com/md/html/dr ... monics.php

Loads of other info out there....(yup - I looked it up too when I was flummoxed!).

If your vibration goes away in neutral, that's likely your problem.
If it stays you're looking at an imbalance in the motor/ flex/ damper/ 'verter.
I had issues with my gearbox/ prop/ diff relative angles. I had to pack my gearbox mount and drill extra holes in the motor plate to sort it.
It didn't help as my problem was actually the rear wheels being massively out of balance, check out the weights in the pic!

I used this guide and invested a well-spent £34 on a digital level

sinny · Post by **sinny** » Tue Oct 28, 14 9:00 pm

UJ's are new Gary, but I'll try the gears.

Thanks for the info Paul I've got a gauge & will take a proper look at the weekend.

that's a lot of weights!

Derek · Post by **Derek** » Tue Oct 28, 14 10:11 pm

I had a similar problem a few years ago, it was the harmonic balancer, the slot that the woodruff key fits into had widened slightly.

sinny · Post by **sinny** » Wed Oct 29, 14 12:50 pm

I'll take a look at that too, thanks Derek.

Stu Twin · Post by **Stu Twin** » Wed Oct 29, 14 1:28 pm

Hi Sinny, I used a propshaft place in St Neots for both our cars. Very good service and just a mile of so from the A1 Jct.
Bailey Morris:

http://www.baileymorris.co.uk/bespoke.html

A bit nearer than Coventy.

sinny · Post by **sinny** » Wed Oct 29, 14 9:16 pm

Cheers Dtu, but I pretty certain the prop isn't the issue but will know more at the weekend................. Hopefully!!

sinny · Post by **sinny** » Sun Nov 02, 14 6:16 pm

Well, had her on jack stands running at 65mph, prop is spinning nice & smooth, so are the wheels, trans tail mount is good.
The headers seemed to be shaking a bit during the vibration.

Tried shifting into 2nd but vibration still there, shifted into neutral but it didn't seem to come out of drive! Still accelerated as if it was in drive (although it rolls freely when motor is off)???

so is it the harmonic balancer (but wouldn't I get it during revving)
Or the flex plate?
Or a internal trans issue?

terryr · Post by **terryr** » Mon Nov 03, 14 8:56 am

You may have done your tailshaft due to that old prop

Look fot cracks around the speedo drive area.ive had the same.lightly jack the box on the pan area .make sure you spread the load..and any crack will open up

Dave-R · Post by **Dave-R** » Mon Nov 03, 14 9:16 am

Any tiny thing can do it.

I once had a mild vibration I took ages to find the source of. In the end it turned out to be a paint run on the front of the damper from when I painted the block. It meant the crank pulley was not seated exactly flat.

It doesn't take much.

sinny · Post by **sinny** » Mon Nov 03, 14 6:42 pm

I'll check the tail but it's not a little thing as the vibration is intense!