fault finding Drive chain

[flyer295]

When you were working on the OD did you remove the roller uni-clutch?

 

Yes I did.

[AlanT]

Do you know for sure that you did not fit this the wrong way round?

 

http://www.buckeyetriumphs.org/technical/AOD/AOD3/AOD3.htm

[flyer295]

Alan,

 

From what I remember I don't think that's possible. Is it?

 

Bob

[peejay4A]

Apparently it is possible:

 

"If an attempt is made to turn the inner member counterclockwise, the clutch will lock. (If it doesn't lock, then the the ramps are probably not positioned as shown in photo and it must be taken apart and reassembled, making sure the spring is installed in the correct direction.)"

[flyer295]

You've put a doubt in my mind, and there is no way of checking it with stripping it down completely again. Or is there?

 

Question - If I have put this un-clutch in the wrong way would that give the symptoms I've got ? Bearing in mind that with no load on the wheels turn freely. The severe vibration I seemed to have cured by changing the prop shaft with one that's never been taken apart.

 

Bob

[AlanT]

Run the engine and OD with no propshaft fitted. Use a foward gear.

Either pin the operating lever in OD or keep the solenoid activated all the time.

Run a minute or so and stop the engine.

 

A good accumulator will hold the pressure and keep you in OD even though you are not rotating.

 

You can now grasp the output flange and feel the uni-clutch action. It won't stay long so be quick.

You will need to know in advance the normal and reverse rotating directions.

 

After a few seconds there should be a "clonk" as the OD drops out and you can check its gone free in both directions.

 

I NEED HARDLY SAY THERE ARE SOME HAZARDS IN DOING THIS!

Work through in your mind the things that might go wrong and take care.

 

Here is a picture of me doing this on a test rig. You can see 450psi on the gauge and its clearly not running.

There is a 3/16in pin in the lever. Stays like this about 30 secs. Obviously enough time to take a photo!

https://www.flickr.com/gp/90670218@N04/5C664o

Edited May 28, 2014 by AlanT

[AlanT]

I can't, for obvious reasons, tell you exactly what happens if you mis-assemble the uni-clutch.

BUT

the clutch rollers have to run up the ramps before it locks which may take about one turn on the shaft.

AND

they may not run up until there is some load

AND

it does jam the transmission

AND

the test is not hard to do.

[flyer295]

Alan,

 

I'll give it a go later.

 

To make it clear when carrying out this test, The flange should lock up in the direction of forward motion or reverse motion? The former I assume.

 

Bob

[flyer295]

Alan.

 

I did the test as you described except for fitting a pressure gauge, I did that once before and got in excess of 400 psi.

 

The result was that the uni clutch could be felt quite distinctly as you said. HOWEVER, The flange was free to rotate in the forward direction of rotation but locked up in the reverse direction.

 

Is this correct ?

 

Bob

[AlanT]

Thats how mine is.

[Peter Cobbold]

Direction of forward motion means the od/prop flange rotating anti-clockwise when you're looking forward at it. Right?

[flyer295]

Peter,

 

Yes that's correct. So it seems that the uni-clutch is in correctly fitted. Phew!

 

I've spoken to Peter Cox at Moss's and he reckons it's the overdrive not disengaging. He's suggested I remove the operating valve and drill out the cross hole at the base of the ridges from 0.029" to 040 (1mm). I'm going to try that next.

 

Tried that, No difference.

 

B

[AlanT]

Well the test proved the OD does not stick if the pressure drops.

 

You can manually flick the operating-lever back and foward to check the OD disengages.

 

Probably be obvious that the speed of the flange reduces especially if you put a white stripe on it.

[Peter Cobbold]

Clutch faces stuck together? Time for a walloping with a heavy hide mallet ?

 

Waaay out of my comfort zone now....

 

Peter

Edited May 28, 2014 by Peter Cobbold

[flyer295]

I know the solenoid is a bit sticky so I moved the adjustment lever by putting a screwdriver between the solenoid and the stop then manually pushing it down again after removing it. I could hear the o/d engage as there's slight bearing noise that went as soon as it was activated. I thought I could detect a slowing down of the flange. I'll confirm that tomorrow with a white stripe on it.

 

With the lever right down and one wheel off the ground, in effect the o/d disengaged, the flange could be turned either way.

I then lowered the car to the ground and tried it.

 

Still the same problem !

 

Bob

[flyer295]

Clutch faces stuck together? Time for a walloping with a heavy hide mallet ?

 

Waaay out of my comfort zone now....

 

Peter

Wouldn't have thought so, it's all brand new. Again the clutch seems to operate correctly.

 

Not very keen on hitting things!

 

Bob

[Peter Cobbold]

So lets recap. Assume the o/d is fine. The diff seems to be OK: wheels turn OK, either locked, and the diff pinion can turn four times ( ie once round the crown wheel) and has no big play.

But the transmission locks up after roughly one turn of the prop shaft either way. But with the wheels off the ground its fine: torque loading is needed to show up the problem.

Pressing the clutch removes the lock up without anything you can see turning. As if something has 'wound up'.

 

So:

Maybe try to hear a noise when you press the clutch to release the lock-up?

The stiff gearchange might be a clue. Maybe torque is shifting a gear cluster slightly so two engage at once?

 

Peter

[AlanT]

Did you do anything with the OD tailshaft bearings?

[flyer295]

So lets recap. Assume the o/d is fine. The diff seems to be OK: wheels turn OK, either locked, and the diff pinion can turn four times ( ie once round the crown wheel) and has no big play.

But the transmission locks up after roughly one turn of the prop shaft either way. But with the wheels off the ground its fine: torque loading is needed to show up the problem.

Pressing the clutch removes the lock up without anything you can see turning. As if something has 'wound up'.

 

So:

Maybe try to hear a noise when you press the clutch to release the lock-up?

The stiff gearchange might be a clue. Maybe torque is shifting a gear cluster slightly so two engage at once?

 

Peter

Your synopsis is just about spot on. 'Winding up' or 'wedging' is a good description of the problem.

 

Very hard to hear any 'releasing noises' from within. The twin ss exhaust don't help with that although a stethoscope helps. Nothing detected.

 

I am concerned about the stiff gear selection and change. I could easily take off the top off. The whole box seems "clunky" are they normally?

 

Do you think that winding the solenoid stop down a bit might help? It would then do away with any possible problem with not disengaging the o/d.

 

Bob

[flyer295]

Did you do anything with the OD tailshaft bearings?

I don't think I did as it was difficult to remove without special equipment but I'm not sure, it was some time ago. I did replace the oil seal.

[AlanT]

My gbox is quite stiff when the oil is cold.

But then I have gear-oil not the thinner oil some people like.

 

Is 2nd gear stiffer than 3rd and top?

 

You are right about the tail-shaft. This is one of the hardest things I've had apart.

 

Take the top off and check the reverse gear selector is assembled right.

 

Getting two foward gears at once would be hard but getting reverse and foward at the same time would be easy.

You would only need to have the thing that moves the idler to be loose somehow.

Edited May 28, 2014 by AlanT

[flyer295]

I'll give it a try so long as "her in doors" approves, which I doubt !!!

[flyer295]

Removed the top of the box. Everything looks ok put a little more hypoid oil in to make sure the level was ok.

 

I tried the overdrive with the rear flange marked. As soon as it engaged the speed increased but it nearly shook itself to pieces. Could that be a wheel problem, they are supposed to be balanced. I'm suffering with a misfire at the moment which doesn't help, need a couple of new injectors.

 

Still nothing obvious.

 

Bob

[Peter Cobbold]

Removed the top of the box. Everything looks ok put a little more hypoid oil in to make sure the level was ok.

 

I tried the overdrive with the rear flange marked. As soon as it engaged the speed increased but it nearly shook itself to pieces. Could that be a wheel problem, they are supposed to be balanced. I'm suffering with a misfire at the moment which doesn't help, need a couple of new injectors.

 

Still nothing obvious.

 

Bob

Are the wheels on full droop when it shakes, axle stands under the chassis,- or is the rear supported under the trailing arms? Running at full droop I could see being shaky, never tried it myself!

The speed only rises ca 25% with o'd in, cant see that making a lot of out of balance shaking.

Peter

[flyer295]

Well yes it was. I'd just quickly jacked it up on the chassis, not that it droops much. The whole suspension is suspect as the rubber stops hardly clear. The springs that came with the car/wreck may have been the wrong ones. I was going to sort that out at a later date. Couldn't be that that's causing the prob could it?

 

Bob