Throwout Bearing/Pilot Bearing Issue Diagnosis

[BudP]

Over the years I have had two throwout bearings go on me, one with bad consequences because I tried to drive home rather than call AAA. This Saturday I will be helping an acquaintance diagnosis what he believes is a transmission noise that is getting worse. Below is a diagnostic/remedy process I now follow. Feel free to criticize, amend, etc.:

TRANSMISSION NOISE
FORD MODEL A


Symptom: Noise from transmission, effected by clutch pedal movement.

Clutch Throw Out Bearing Noise: high-pitched rubbing noise with only slight
pressure on clutch.

Pilot Bearing Noise: high-pitched noise when clutch is fully depressed.

Noise When Clutch Pedal Depressed:
-throwout bearing, worn, damaged, inadequately lubricated
-pilot bearing (in flywheel) worn, damaged, inadequately lubricated
-transmission front shaft bearing worn, damaged, inadequately lubricated

Noise When Clutch Pedal Released:
-Misalignment of transmission (more noticeable at low road speed)
-Clutch disk hub loose
-Clutch disk springs weak or broken
-Weak or broken throwout bearing sleeve return spring
-Sticking throwout bearing sleeve (clean slider, lubricate)

Other deceiving noises that can “travel” include noise from speedometer cable, starter Bendix, generator bearing/bushing, and water pump bearing.

Firstly, grease the throwout bearing sleeve. If noise is eliminated, good.

Secondly, if noise still around, adjust the clutch for one inch of free play. If noise is eliminated, good.

Thirdly, if noise is still present, the transmission will need to be separated from engine. Best to remove rear end and drive train, unless major engine work is required.

[tbirdtbird]

Lookin' good. Somewhere on that list find a place for
1. disc spring popped out of uncaged disc
2. worn/damaged roller bearing(s) in tranny

[Mitch]

Noise When Clutch Pedal Depressed:
-throwout bearing, worn, damaged, inadequately lubricated
-pilot bearing (in flywheel) worn, damaged, inadequately lubricated
-transmission front shaft bearing worn, damaged, inadequately lubricated

Lets see
With the clutch pedal Depressed the trans input shaft bearing should not be spinning. With the clutch pedal released the input shaft bearing will be spinning

[Mitch]

With the input shaft spinning the cluster gear is rotating. The cluster gears have roller bearings on the ends, and the input shaft has roller bearings where it mates to the main shaft. All of these come into play for noises.

Bud i like this list idea. It would be a good addition to the powertrain tech thread forum. I don't think we have a transmission thread in there yet.

[BudP]

Yup-it's been a few years since I've had to deal with a noisy trans. I'll wait until Saturday when I get my hands into a trans, and then I will rewrite this to account for your and TBird's comments, plus any others I may receive. I do like the idea of written protocols for diagnosis and correction so I'll take another stab at this over the weekend. All comments, suggestions, criticisms welcome.

[tbirdtbird]

caution on replacing the roller bearings, there are badly made ones and well made ones. The bad ones do not have axles that go all the way through, just dimples on the end plates to hold the rollers in place

[BNCHIEF]

To follow onto Tbirds post pics of the poorly made bearings as well as the good bearings and why as well as sources for the good parts. Good list you have started there Bud.

[Mitch]

Bud when you get the list revised, we can post it in the tech area. Nice job and thanks for starting this

[Vin1930]

I am Bud’s acquaintance, and just got everything buttoned back up today. Now NOISELESS throwout bearing. Thanks, Bud!

[Mitch]

You're in good hands with Bud

Thanks for the update and glad it's resolved

[BudP]

So glad you got it done, Jeff-and with your young son learning as he helped you! He will always have this memory!

[Captndan]

I’m going thru the same thing now and have been for months. The problem was diagnosed and is being fixed by a mutual friend. This is sort of the second time around. The guy that put the new clutch disc, throw out bearing, and pilot bushing forgot or didn’t know the bearing must be packed before putting it in. Know your mechanic!

[Mitch]

The replacement bearings are sealed, and do not need packing or servicing. I only use a good quality federal mogul or like.

[Captndan]

I should have said this is not a Ford

[CM2]

dont forget to dial in your flywheel housing,crankshaft to transmission main shaft alignment is critical.