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MG TD TF 1500 - Trans, getting a knock.

I probably know the answer, but before I tear into it I'd like a second opinion or two.

I've picked up a knock under acceleration in the gear shift. It appears in 3rd and 4th. For a description: It almost feels like one cylinder is firing at 200% and kicking the driveline.

It goes away when coasting either in gear or not in gear. The engine is running very smoothly, compression tests are fairly even and all cylinders are firing. The U-joints were just replaced, the drive shaft just balanced and the rear axle is from Dave Clark. All have under 50 miles on them.

I posted a short Youtube:

http://youtu.be/_Iujv54e5DQ

I'm pretty sure that much backlash is a bit too much, even for our cars.

Thanks.
MAndrus

Mitch,

I think that your bolts on the U-joints are in backwards. The nuts to my recollection should be facing out with the head in so that there is no interference with the yoke. Mark
Mark Strang

Mark, That's the way they came out. Prob wrong way 'round, but they clear by 1/4".

....
MAndrus

Since it appears to be in neutral, could the knock be coming from the rear end? You may want to pull one end of the driveshaft and try again to verify where it is coming from.
George Butz

gear selector loose/indent balls

could be wrong, often am
mog

Mitch,

Tried mine and can not duplicate the sound on the video. Just a click as far as my hearing aids can determine. Also agree with above. Bolts on mine are nuts to the rear. Who knows if this is important.

Hope the clunk is minor.

Regards,

Jim haskins 1953 TD
J. M. Haskins

Try George's test. I would expect that you'd get the same noise with the driveshaft uncoupled, i.e., by turning the output flange. BTW, I agree with the folks about the orientation of the nuts/bolts. Bud
Bud Krueger

Let me elaborate.

The 'Knocking' is persistent. and gains speed as the car goes faster.

Knock knock knock knock knock knockknockknockknockknockknockknockknockknock.

Almost like a gear has lost a tooth or the laygear's shaft has gone oval or reverse gear and shaft are kaput.

.....
MAndrus

Mitch,

Have you checked the oil in the box? It almost sounds like it is dry?

Just a thought.
Rod
R. D. Jones

RD, lots of oil.

Striped the interior and going for a drive tomorrow for a better listen.

....
MAndrus

Mitch,
How did this noise develop? Did it happen all of a sudden.....or has it been going on a while and getting worse?

"The 'Knocking' is persistent. and gains speed as the car goes faster.
Knock knock knock knock knock knockknockknockknockknockknockknockknockknock.
Almost like a gear has lost a tooth"

That is an exact description of the symptoms I experienced when I broke a tooth on the Laygear. All at once...pulling away from a Stop Sign...knock knock knock knock.

But you say..."I've picked up a knock under acceleration in the gear shift. It appears in 3rd and 4th." Is it really in the shifter? Does it change, tone, volume when you lay your hand on it? It very well could be transmitting noise/vibration.

But only in 3rd/4th. And the Video. You are moving the Output Shaft/Mainshaft, and only the 1st/2nd Hub, and the 3rd/4th Hub is splined to that Shaft.
I can duplicate a similar sound by rocking the Output back and forth...but there is a couple places in the Video where you turn it further in the same direction...and you can hear a click click click.
The Shaft Bearings(3) are moving.
I can't figure out why it is only in 3rd/4th.

Mike-TF8257

M Brand

Hate to say it, but it just isn't going to get well on its own, is it. Time to get in there, I reckon.

David
David Provan

Yea.... It's gotta come out. With the trans hump out of the car, I did a few stop and goes, took a few hills, hung in 2nd & 3rd too long. What a racket.

Not a gears grinding together noise, more of a rattling "I needs me some new needle bearings" noise.

I hope that's all it is.

...
MAndrus

This thread was discussed between 08/06/2015 and 09/06/2015

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