how do you diagnose a bad u-joint?

[ElGranadaT]

Hello again T Owners,

My T has a VERY loud grinding noise coming from the transmission area only when in 'hi gear' ...

Its frequency is in sync with the engine RPM -

Now, the engine runs fine, and the transmission has new bands, a new brake drum and the clutch plates were replaced and all adjusted by Pete Rich, who is a terrific master T mechanic in the area...


The questions for today are...

what are the typical symptoms of a worn out U-joint?

Can I inspect it through the Transmission cover?

I'm assuming I need to pull the entire rear end, with the tube- to replace it -

thanks yet again to all

This has been terrific having all you helping me with this project-

[Moxie26]

The sounds you hear could be coming from a few sections of the drive train.... ring & pinion gear noise from worn bushings, worn roller bearings, worn ball cap bushing, worn drive shaft bushing, engine with misaligned engine pan. U-Joint inspection involves ball cap bolt removal and disconnecting from engine for physical inspection. If differential is on stands, wheels can be turned fore and aft to hear "clunks" from the UV before your wheel movement starts to turn engine crank.

[TWrenn]

Strange as this may sound, have you removed the grease cup or the little plug and peeked inside the ball as best you can? To see if there's ANY evidence of much grease? Or even stick a thin screwdriver or wire in to see/feel for any? Reason I say this, the U joint is often neglected even when people DO crank down a few cups full of grease. That's why I always hawk the grease cup with zerk and give LOTS of pumps on the gun! Reason I say this, is there's not much evidence of much grease, it very may well be the ujoint worn out.

[speedytinc]

Remove the large grease cup unit. You will have some visual access thru the 1/4" pipe thread hole.
Next step would be to remove the 4 ball cap bolts & slide the flange back. That will give you access to a larger 3/4" hole.
You will be able to see all 4 joints (as the rear wheels are rotated) & evaluate the wear/condition & grease level.
With a screwdriver try to move the u-joint front & back. It should not easily move unless the pin is sheared or missing.
A missing /sheared pin will allow the pinion gear to engage more tightly into the ring gear, making more noise.

A loose/destroyed D/S bearing/inner race will make horrendous noise that sounds like its coming from the transmission.
I have experienced this during primarily load/acceleration conditions.

[Jerry VanOoteghem]

If you remove the 4 bolts that hold the ball socket retaining ring in place, and slip the ring back, it will expose a hole in the torque tube ball that will be a pretty good "window" to peek at the u-joint. You could also just remove the large grease cup and look through its mounting hole, but it's not as big an opening as the one in the ball itself.

HA! Looks as if John & I were typing at the same time

[Norman Kling]

You only need to slip the driveshaft back about 6 inches to get the U joint out of the front spline. And you can take out the two plugs over the back end of the U joint and with a punch shove out the pin and then slide the U joint forward to remove it. First inspect the joint and try rotating it while it is still on the driveshaft. You can tell if the slack is in the U joint or farther back in the rear axle. If the U joint is tight, it should be OK. The 4th main can also be removed easily when you pull the U joint back and inspect for wear. You might need to replace it. If you do replace, measure the diameter of the output shaft and might need an undersize 4th main.
Norm

[TRDxB2]

Hello again T Owners,

My T has a VERY loud grinding noise coming from the transmission area only when in 'hi gear' ...
Its frequency is in sync with the engine RPM -
Now, the engine runs fine, and the transmission has new bands, a new brake drum and the clutch plates were replaced and all adjusted by Pete Rich, who is a terrific master T mechanic in the area...
The questions for today are...
--what are the typical symptoms of a worn out U-joint?
Can I inspect it through the Transmission cover?
I'm assuming I need to pull the entire rear end, with the tube- to replace it -
thanks yet again to all
This has been terrific having all you helping me with this project-

Its not a good idea to pre-diagnose an problem on the forum as to what you think the problem is. It causes others to miss your initial description. Its best to let others offer their initial solution/checking based on your description of events.

So to start over you said "
My T has a VERY loud grinding noise coming from the transmission area only when in 'hi gear' ...
Its frequency is in sync with the engine RPM -
Now, the engine runs fine, and the transmission has new bands, a new brake drum and
the clutch plates were replaced and all adjusted by Pete Rich, who is a terrific master T mechanic in the area...
Noise https://www.mtfca.com/phpBB3/viewtopic. ... 51&p=37350
Adjust https://modeltfordfix.com/adjusting-the ... nd-clutch/

--
Multiple discussion on possible U-joint noise https://www.bing.com/search?form=MOZLBR ... oise+mtfca

[Craig Leach]

Hi Martin,
Just to add to the many ideas, jack up one wheel, remove the 2578 drive shaft housing plug. Rotate the rear wheel that is jacked up till the
U/joint pin is aligned with the hole & check to see if it has come loose and is grinding in the drive shaft tube casting. I've seen it happen.
Craig.

[ElGranadaT]

The sounds you hear could be coming from a few sections of the drive train.... ring & pinion gear noise from worn bushings, worn roller bearings, worn ball cap bushing, worn drive shaft bushing, engine with misaligned engine pan. U-Joint inspection involves ball cap bolt removal and disconnecting from engine for physical inspection. If differential is on stands, wheels can be turned fore and aft to hear "clunks" from the UV before your wheel movement starts to turn engine crank.

Good advice! THANK YOU!

[ElGranadaT]

Strange as this may sound, have you removed the grease cup or the little plug and peeked inside the ball as best you can? To see if there's ANY evidence of much grease? Or even stick a thin screwdriver or wire in to see/feel for any? Reason I say this, the U joint is often neglected even when people DO crank down a few cups full of grease. That's why I always hawk the grease cup with zerk and give LOTS of pumps on the gun! Reason I say this, is there's not much evidence of much grease, it very may well be the ujoint worn out.

Hi - Are you saying low grease can cause this noise?

[ElGranadaT]

If you remove the 4 bolts that hold the ball socket retaining ring in place, and slip the ring back, it will expose a hole in the torque tube ball that will be a pretty good "window" to peek at the u-joint. You could also just remove the large grease cup and look through its mounting hole, but it's not as big an opening as the one in the ball itself.

HA! Looks as if John & I were typing at the same time

This is definately on the list - but I don't have the cup yet - I do have a hole about 1/2 inch diameter on the hemisphere - cover. and I pack as much grease as I can into that-

[ElGranadaT]

Remove the large grease cup unit. You will have some visual access thru the 1/4" pipe thread hole.
Next step would be to remove the 4 ball cap bolts & slide the flange back. That will give you access to a larger 3/4" hole.
You will be able to see all 4 joints (as the rear wheels are rotated) & evaluate the wear/condition & grease level.
With a screwdriver try to move the u-joint front & back. It should not easily move unless the pin is sheared or missing.
A missing /sheared pin will allow the pinion gear to engage more tightly into the ring gear, making more noise.

A loose/destroyed D/S bearing/inner race will make horrendous noise that sounds like its coming from the transmission.
I have experienced this during primarily load/acceleration conditions.

so far the best advice! moving the u-joint fore and aft makes perfect sense... but hat is a D/S BEARING?

[ElGranadaT]

You only need to slip the driveshaft back about 6 inches to get the U joint out of the front spline. And you can take out the two plugs over the back end of the U joint and with a punch shove out the pin and then slide the U joint forward to remove it. First inspect the joint and try rotating it while it is still on the driveshaft. You can tell if the slack is in the U joint or farther back in the rear axle. If the U joint is tight, it should be OK. The 4th main can also be removed easily when you pull the U joint back and inspect for wear. You might need to replace it. If you do replace, measure the diameter of the output shaft and might need an undersize 4th main.
Norm

Hi Norm!

Sounds liek you've been here more than once-
to move the driveshaft back 6 in. I agther i need to drop the rear dif???

[ElGranadaT]

Hello again T Owners,

My T has a VERY loud grinding noise coming from the transmission area only when in 'hi gear' ...
Its frequency is in sync with the engine RPM -
Now, the engine runs fine, and the transmission has new bands, a new brake drum and the clutch plates were replaced and all adjusted by Pete Rich, who is a terrific master T mechanic in the area...
The questions for today are...
--what are the typical symptoms of a worn out U-joint?
Can I inspect it through the Transmission cover?
I'm assuming I need to pull the entire rear end, with the tube- to replace it -
thanks yet again to all
This has been terrific having all you helping me with this project-

Its not a good idea to pre-diagnose an problem on the forum as to what you think the problem is. It causes others to miss your initial description. Its best to let others offer their initial solution/checking based on your description of events.

So to start over you said "
My T has a VERY loud grinding noise coming from the transmission area only when in 'hi gear' ...
Its frequency is in sync with the engine RPM -
Now, the engine runs fine, and the transmission has new bands, a new brake drum and
the clutch plates were replaced and all adjusted by Pete Rich, who is a terrific master T mechanic in the area...
Noise https://www.mtfca.com/phpBB3/viewtopic. ... 51&p=37350
Adjust https://modeltfordfix.com/adjusting-the ... nd-clutch/
trans noise.png
--
Multiple discussion on possible U-joint noise https://www.bing.com/search?form=MOZLBR ... oise+mtfca

[ElGranadaT]

general reply to all:
thanks for all the advice- I'll start pulling things apart withing the next few days and report on what I find.

[TWrenn]

Strange as this may sound, have you removed the grease cup or the little plug and peeked inside the ball as best you can? To see if there's ANY evidence of much grease? Or even stick a thin screwdriver or wire in to see/feel for any? Reason I say this, the U joint is often neglected even when people DO crank down a few cups full of grease. That's why I always hawk the grease cup with zerk and give LOTS of pumps on the gun! Reason I say this, is there's not much evidence of much grease, it very may well be the ujoint worn out.

Hi - Are you saying low grease can cause this noise?

What I'm saying is, if there's not sufficient grease in the ball cap then you're inviting extra wear and tear and eventual failure. There really is lots of movement in the U -joint, and where everything connects must be bathed in lube all the time. 3 or 4 "turns of a cup full" just don't get it in my book, unless you're starting out with a FULLY PACKED ball in the first place.

[Jerry VanOoteghem]

Strange as this may sound, have you removed the grease cup or the little plug and peeked inside the ball as best you can? To see if there's ANY evidence of much grease? Or even stick a thin screwdriver or wire in to see/feel for any? Reason I say this, the U joint is often neglected even when people DO crank down a few cups full of grease. That's why I always hawk the grease cup with zerk and give LOTS of pumps on the gun! Reason I say this, is there's not much evidence of much grease, it very may well be the ujoint worn out.

Hi - Are you saying low grease can cause this noise?

Yes. The same way that running your engine without any oil can cause noise... and engine failure.

Running your u-joint without sufficient grease will destroy it. Once ruined, it will then make noise. (and eventually smoke!)

[TRDxB2]

Hello again T Owners,

My T has a VERY loud grinding noise coming from the transmission area only when in 'hi gear' ...
Its frequency is in sync with the engine RPM -

Now, the engine runs fine, and the transmission has new bands, a new brake drum and the clutch plates were replaced and all adjusted by Pete Rich, who is a terrific master T mechanic in the area...
........................
thanks yet again to all

This has been terrific having all you helping me with this project-

Would someone explain how a u-joint would make noise, consistent with RPM, but only in high gear. I would expect that given the same RPM in low gear there would be comparable noise from the u-joint.

[Jerry VanOoteghem]

Hello again T Owners,

My T has a VERY loud grinding noise coming from the transmission area only when in 'hi gear' ...
Its frequency is in sync with the engine RPM -

Now, the engine runs fine, and the transmission has new bands, a new brake drum and the clutch plates were replaced and all adjusted by Pete Rich, who is a terrific master T mechanic in the area...
........................
thanks yet again to all

This has been terrific having all you helping me with this project-

Would someone explain how a u-joint would make noise, consistent with RPM, but only in high gear. I would expect that given the same RPM in low gear there would be comparable noise from the u-joint.

I am assuming that while in low gear, the car is not going as fast as it would be while in high gear, and that the noise is worse at higher speeds.

[TRDxB2]

Hello again T Owners,

My T has a VERY loud grinding noise coming from the transmission area only when in 'hi gear' ...
Its frequency is in sync with the engine RPM -

Now, the engine runs fine, and the transmission has new bands, a new brake drum and the clutch plates were replaced and all adjusted by Pete Rich, who is a terrific master T mechanic in the area...
........................
thanks yet again to all

This has been terrific having all you helping me with this project-

Would someone explain how a u-joint would make noise, consistent with RPM, but only in high gear. I would expect that given the same RPM in low gear there would be comparable noise from the u-joint.

I am assuming that while in low gear, the car is not going as fast as it would be while in high gear, and that the noise is worse at higher speeds.

No question about your assumption. But the problem states that the noise is consistent with engine RPM speed in Hi gear only. Shifting from Low to High changes the RPM of the engine not the RPM of the u-joint (assuming no drastic acceleration). Having said that, one would expect some noise in low gear just before shifting to high since the u-joint would be rotating at the same speed. What I am getting at here I would expect noise in Low gear at the same car speed (not engine RPM) as in high gear if the u-joint is the culprit. Couldn't this be a test?

[Jerry VanOoteghem]

Would someone explain how a u-joint would make noise, consistent with RPM, but only in high gear. I would expect that given the same RPM in low gear there would be comparable noise from the u-joint.

I am assuming that while in low gear, the car is not going as fast as it would be while in high gear, and that the noise is worse at higher speeds.

No question about your assumption. But the problem states that the noise is consistent with engine RPM speed in Hi gear only. Shifting from Low to High changes the RPM of the engine not the RPM of the u-joint (assuming no drastic acceleration). Having said that, one would expect some noise in low gear just before shifting to high since the u-joint would be rotating at the same speed. What I am getting at here I would expect noise in Low gear at the same car speed (not engine RPM) as in high gear if the u-joint is the culprit. Couldn't this be a test?

Well, let's remember, he only asked how to diagnose a bad u-joint. He never stated that it was the cause of his troubles.

Nobody is really going to know anything until the rear end is removed and inspected, which has to happen anyway, since speculation and theorizing at great distances will ultimately repair nothing.

[ElGranadaT]

You only need to slip the driveshaft back about 6 inches to get the U joint out of the front spline. And you can take out the two plugs over the back end of the U joint and with a punch shove out the pin and then slide the U joint forward to remove it. First inspect the joint and try rotating it while it is still on the driveshaft. You can tell if the slack is in the U joint or farther back in the rear axle. If the U joint is tight, it should be OK. The 4th main can also be removed easily when you pull the U joint back and inspect for wear. You might need to replace it. If you do replace, measure the diameter of the output shaft and might need an undersize 4th main.
Norm

HI Norm... very good recommendation. Thank you. I can't seem to find a 4th main in the manual.. Is that in the torque tube?

[ElGranadaT]

Hello again T Owners,

My T has a VERY loud grinding noise coming from the transmission area only when in 'hi gear' ...
Its frequency is in sync with the engine RPM -

Now, the engine runs fine, and the transmission has new bands, a new brake drum and the clutch plates were replaced and all adjusted by Pete Rich, who is a terrific master T mechanic in the area...
........................
thanks yet again to all

This has been terrific having all you helping me with this project-

Would someone explain how a u-joint would make noise, consistent with RPM, but only in high gear. I would expect that given the same RPM in low gear there would be comparable noise from the u-joint.

Duh.. good point! Still it's where the clunking seems to be emanating. My next step is first jack up one rear wheel and have someone move it. I'll go down the drive train with my trusty mechanics stethoscope and listen for metal on metal. . Next step is jack up both rear wheels and drop it into gear and listen again...

[ElGranadaT]

Hello again T Owners,

My T has a VERY loud grinding noise coming from the transmission area only when in 'hi gear' ...
Its frequency is in sync with the engine RPM -

Now, the engine runs fine, and the transmission has new bands, a new brake drum and the clutch plates were replaced and all adjusted by Pete Rich, who is a terrific master T mechanic in the area...
........................
thanks yet again to all

This has been terrific having all you helping me with this project-

Would someone explain how a u-joint would make noise, consistent with RPM, but only in high gear. I would expect that given the same RPM in low gear there would be comparable noise from the u-joint.

Duh.. good point! How did I miss that? Still it's where the clunking seems to be emanating. My next step is first jack up one rear wheel and have someone move it. I'll go down the drive train with my trusty mechanics stethoscope and listen for metal on metal. . Next step is jack up both rear wheels and drop it into gear and listen again...

[TWrenn]

Hello again T Owners,

My T has a VERY loud grinding noise coming from the transmission area only when in 'hi gear' ...
Its frequency is in sync with the engine RPM -

Now, the engine runs fine, and the transmission has new bands, a new brake drum and the clutch plates were replaced and all adjusted by Pete Rich, who is a terrific master T mechanic in the area...
........................
thanks yet again to all

This has been terrific having all you helping me with this project-

Would someone explain how a u-joint would make noise, consistent with RPM, but only in high gear. I would expect that given the same RPM in low gear there would be comparable noise from the u-joint.

Duh.. good point! How did I miss that? Still it's where the clunking seems to be emanating. My next step is first jack up one rear wheel and have someone move it. I'll go down the drive train with my trusty mechanics stethoscope and listen for metal on metal. . Next step is jack up both rear wheels and drop it into gear and listen again...

Sadly there's so many possibilities of this noise from "stem to stern"...if indeed it's the U joint..one thing about "clunking" could be very well a great amount of slop where each joint connection is made, again from lack of enough lube over 100 years or so. About the only way to tell that is to at least pull the rear end so you can access it and really get a literal "hands on check". Frankly, I'd bite the bullet and yank out the rear end. It's not as intimidating as it looks and sounds. I've done 4 over the years and it's not bad. I even seem to get 'em out a slightly different way each time!

[Jerry VanOoteghem]

As Tim suggests, and as I mentioned above, even if you found out exactly what the problem is, it still needs to come apart in order to fix it. Might as well get started.

[ElGranadaT]

Greetings all -

THANK YOU! for all the great advice and information. I've opened up the ball, and top inspection lid- and I'm now focusing on the 4th main - one thing I neglected to mention- that I should have -was it does have a regular oil leak at the ball - Also - when I pulled the engine I don't seem to recall that the 4th main was at all a good fit- I'll be pulling the rear end later today and keep you all posted.

[Jerry VanOoteghem]

Greetings all -

THANK YOU! for all the great advice and information. I've opened up the ball, and top inspection lid- and I'm now focusing on the 4th main - one thing I neglected to mention- that I should have -was it does have a regular oil leak at the ball - Also - when I pulled the engine I don't seem to recall that the 4th main was at all a good fit- I'll be pulling the rear end later today and keep you all posted.

Sounds good Martin! Show us some pictures as you go.

[ElGranadaT]

Well -

I pulled the rear axle assembly. Really not half as bad as I thought it would be - (maybe 2-3 hrs)

The result is that the 4th main and universal joint are clearly worn out. A lot of play and rattle.

Since I've come this far- and the engine and trans has already been gone through 100% I guess it's inevitable...
I'll do a full rear axle / tube overhaul.

Thanks again lads and lassies!

Great having you all here to help...

keep em' flyin'

[speedytinc]

Its concerning to me that the "4th main...are clearly worn out." This is part of a complete transmission rebuild.
Why wasn't the bad u-joint seen during the transmission work when the motor was out?
How can you confirm the crank case is in alignment with a worn out 4th main? Will the new 4th main fit properly to the pan?

Its a good thing your thoughts on a bad u-joint were found. That should net you more usable parts in your rear end.
A completely restored drive line will provide many thousands of trouble free miles.

[TWrenn]

Well -

I pulled the rear axle assembly. Really not half as bad as I thought it would be - (maybe 2-3 hrs)

The result is that the 4th main and universal joint are clearly worn out. A lot of play and rattle.

Since I've come this far- and the engine and trans has already been gone through 100% I guess it's inevitable...
I'll do a full rear axle / tube overhaul.

Thanks again lads and lassies!

Great having you all here to help...

keep em' flyin'

Good that you removed it! I told ya it ain't that bad! It's actually kinda fun...but be prepared for a mess when you split the axle housing apart! It could even be "all original " in that the "differential lube" will be a thick stinky almost tar like substance unless someone else has already had it apart. And now this is the time to be sure it has, or WILL have..bronze thrust washers installed in the diff.!

[Art M]

Is it possible that the worniut universal joint would put extreme stress on the 4th main, causing the wear.

Art Mirtes

[Norman Kling]

More likely a crooked crankcase would put stress on the 4th main.
Norm

[speedytinc]

More likely a crooked crankcase would put stress on the 4th main.
Norm

I will second this.

The wearing out can come from the transmission output shaft not running true also.
This condition loosens the output plate & brake/clutch drum rivets also.

[ElGranadaT]

Morning all -

The dif removal was about 2 hrs, and like you said- kind of a fun challenge.

The no. 4 measured 1.590 in - Standard is 1.560 so about 30 thou out- The U joint was also pretty sloppy. Getting a full overhaul of the dif and torque tube- through u joint- along with new no. 4

I'll update all soon

[TWrenn]

Morning all -

The dif removal was about 2 hrs, and like you said- kind of a fun challenge.

The no. 4 measured 1.590 in - Standard is 1.560 so about 30 thou out- The U joint was also pretty sloppy. Getting a full overhaul of the dif and torque tube- through u joint- along with new no. 4

I'll update all soon

Martin....if you can, go on our classifieds and advertise to WTB either a good used U joint or hopefully an NOS....the repops usually don't fit into the trans/driveshaft worth crap!

Otherwise, not a hard job. And as everyone will say...when you're ready to put 'er all together make sure you PACK that "ball" solid with grease, I always use good old fashioned "Red 'n Tacky"....but you're probly already savvy about this...just a friendly reminder is all. Then get one of the large grease cups with the zerk in it from Langs...they're the only one's who sell that model...then I always "preach" that on every oil change, pump a good 20-25 pumps of your grease gun with the same grease of course into the U-joint ball cap. Sounds like a lot, but of course we all know one pump of the gun does not put out a whole heckuva lot of grease. So far, I've had no joint problems with this method....wish my OWN joints were that easily maintained!

[speedytinc]

More likely a crooked crankcase would put stress on the 4th main.
Norm

I will second this.

The wearing out can come from the transmission output shaft not running true also.
This condition loosens the output plate & brake/clutch drum rivets also.

A 4th main doesn't get that sloppy worn by itself.
Slapping a new, better fitting one doesn't solve the problem.
You will have to ensure the new 4th main is correctly positioned in the relationship of the output shaft & hogs head.
Easy job when a motor is vertical, not so easy in the frame. Side to side will be obvious, but up & down Is going to take some common sense to adjust.

[ElGranadaT]

closing the books on this one ---

4th main was badly worn, U joint rattled, and most importantly - the differential was a total mess- Roller bearings, thrust spacers, pretty much everything- Thankfully, I was able to get Pete Rich, in Norther California, to do a full overhaul of it. He found dozens of fragments of the original babbit thrust washers scattered throughout - Thankfully the gears were all ok - I Installed the differential today and the noise is gone - nice - smooth and as quiet as I gather a model T can get...

thanks again for everyone's advice and knowledge- Very much appreciated!

[Jerry VanOoteghem]

closing the books on this one ---

4th main was badly worn, U joint rattled, and most importantly - the differential was a total mess- Roller bearings, thrust spacers, pretty much everything- Thankfully, I was able to get Pete Rich, in Norther California, to do a full overhaul of it. He found dozens of fragments of the original babbit thrust washers scattered throughout - Thankfully the gears were all ok - I Installed the differential today and the noise is gone - nice - smooth and as quiet as I gather a model T can get...

thanks again for everyone's advice and knowledge- Very much appreciated!

Martin,

Thanks for the update! It helps everyone when we know "the rest of the story".