U joint hmmm?

[07gtman]

Had a front bearing issue, and replaced it a few weeks ago, It was humming a bit from the rear got pretty loud last night coming home from work. jacked it up and no play in the wheel, i know does not mean the bearing is not bad. But turned the wheel a bit back and forth, got a clicking sound from the u joint, so again, slowly i turned it back and forth a few times and there is play in that rear u joint..So ever get a humm from a u joint? No clanking from forward to reverse...

 

[Number Twelve]

ever get a humm from a u joint?

No. My Aerostar had a u-joint so bad that it was coughing up rollers and it never made a sound. I could feel the, "out-of-balance" driveshaft in the seat of my pants, but I never heard it.
I do know that one way to test a u-joint is to try to wiggle it every which way. Any slack at all means it's bad.
If you can just feel a, "tick" when you change the direction of your force, it's bad. That tick is the feel of the metal stopping after it moves through the clearance that shouldn't be there.

 

[XploX]

The ring and pinion gears are not meshed tight, they have slight play in them and rotating the tire back and forth can cause a slop feeling... maybe a slight tick sound.
To test the u-joint, raise the rear tires and twist the drive shaft clockwise and then counter-clockwise rapidly. You can feel, see and hear the slop if it's bad.
U-joints don't make a hum noise and if the bearings are bad enough you heard a loud hum, you should have heard a noise when rotating the tires.
Maybe check the differential fluid. Gears get loud when they are dry and chewing apart.

You could also put the rear tires on the front and front on rear to see if the hum disappears on the same road. Tires can hum on certain surfaces more than others with temp changes and a bad belt will cause noise and being on the back is difficult to feel, but if it's on the front, it can be felt.

 

[07gtman]

The ring and pinion gears are not meshed tight, they have slight play in them and rotating the tire back and forth can cause a slop feeling... maybe a slight tick sound.
To test the u-joint, raise the rear tires and twist the drive shaft clockwise and then counter-clockwise rapidly. You can feel, see and hear the slop if it's bad.
U-joints don't make a hum noise and if the bearings are bad enough you heard a loud hum, you should have heard a noise when rotating the tires.
Maybe check the differential fluid. Gears get loud when they are dry and chewing apart.

You could also put the rear tires on the front and front on rear to see if the hum disappears on the same road. Tires can hum on certain surfaces more than others with temp changes and a bad belt will cause noise and being on the back is difficult to feel, but if it's on the front, it can be felt.

I could see the play in the u joint, as i rocked the rear wheel, and have replaced u joints on plenty of cars.. just never had these symptoms, always more like NUMBER TWELVE was saying. Although i think im feeling a bit of the grind or vibration now as well..thank you guys for your thoughts on this....Ps just trying to get rid of these humming sounds..

 

[Number Twelve]

Memory seems to be coming back...Do these tests in the quietest, most comfortable conditions you can achieve.

Place two of the u-joint ends horizontal and push up, then down on the long shaft. Feel for the, "tick". That checks for clearance in the needles that are horizontal. Rotate 1/4 turn so the other set of needles is horizontal and repeat the up-down pressure. Why up and down? Because you are probably going to be on your back with excellent leverage against the floor and both arms working together. You might find some good hand holds to do a lateral jerk, but that isn't where your best muscles are. It's awkward and jerking causes mechanical stimulus to the body that can disguise the subtle "tick" you are feeling for.

What about rotational forces? After all, that's what a u-joint does for a living.
Checking for a rotational movement, you can never pick a single bad set of needles out of the four bearing cups because the other three will make it seem right. Besides, your leverage sucks unless you put two strap wrenches on the drive shaft...one for each direction of rotation.

What about longitudinal movement?
Again, all four needle sets are combining to make the joint look good. Besides, there is a lot of drive shaft mass inertia to overcome in trying to create a longitudinal movement and you would be testing both u-joints in the drive shaft at the same time.

A lateral force obeys the Law of Tangents which basically says you can bend a guitar string under 40 pounds of tension with one finger tip because force approaches infinity if there is zero deflection angle at the point where you inflict force on the string. Same for a u-joint. The better the joint is, the less deflection, and the more your force is multiplied by the Law of Tangents.

If you can tell the joint is bad without setting yourself up for the best mechanical advantage and your best ability sense tiny results, it's a really bad u-joint! And remember, you don't have to believe me. If you know a better way, do it.

 

[07gtman]

1. Number Twelve ...Thanks that was a great right up on this..I could actually see play/slack in the rear u joint just by turning the rear wheel back and forth. the rear u joint is in fact shot. I never heard one of these humm gas on gas off, no klang from reverse to drive silent ...

 

[t99eddieb]

Hi guys..
How difficult is it to remove the driveshaft(s) and inspect and/or replace if I don’t have a lift... Also is it possible to replace both Joints but don’t have a lift or a press? I have an older truck (1999 explorer EB) but it seems like if I am not throwing over $400 bucks to an auto shop store; the service is not worth their time. I would love to get under my car and just do it myself but this will be my first time tackling project this large. I’ve done brakes, rotors, plugs, cables, mufflers, blower fan, a radiator, any and all electronics on this 1999 explorer EB truck over the last 10years... Also, I want to save a little money by ordering my own parts .. not cheaper OEM Chinese parts. But something a little better. I get so upset when you take your car to replace brakes and/or muffler they install Chinese crap that only last a year. I want parts made in the USA.. Most shops I ask to bring my own parts.. (nooooo .. -sorry) . this is not allowed..... WHY???? The last time I installed my own rotors and pads, I did not do OEM and they lasted the longest ever than what any shop has installed... Plus now I learned how to troubleshoot any brake or pad issues.. - sorry for the venting. I've just got 2 different diagnostics from 2 shops... One says u-joints and one says driveshaft balancing..

 

[07gtman]

if you can do brakes you can do the u-joints harbor freight has a ball joint tool that pushes u-joints out fairly easy, if you have a 12 point 1/2 inch socket the drive shaft comes out in about 15 mins after you have all 4 wheels off the ground if you have 4x4...you will need to rotate the shaft...

 

[Mbrooks420]

Hi guys..
How difficult is it to remove the driveshaft(s) and inspect and/or replace if I don’t have a lift... Also is it possible to replace both Joints but don’t have a lift or a press? I have an older truck (1999 explorer EB) but it seems like if I am not throwing over $400 bucks to an auto shop store; the service is not worth their time. I would love to get under my car and just do it myself but this will be my first time tackling project this large. I’ve done brakes, rotors, plugs, cables, mufflers, blower fan, a radiator, any and all electronics on this 1999 explorer EB truck over the last 10years... Also, I want to save a little money by ordering my own parts .. not cheaper OEM Chinese parts. But something a little better. I get so upset when you take your car to replace brakes and/or muffler they install Chinese crap that only last a year. I want parts made in the USA.. Most shops I ask to bring my own parts.. (nooooo .. -sorry) . this is not allowed..... WHY???? The last time I installed my own rotors and pads, I did not do OEM and they lasted the longest ever than what any shop has installed... Plus now I learned how to troubleshoot any brake or pad issues.. - sorry for the venting. I've just got 2 different diagnostics from 2 shops... One says u-joints and one says driveshaft balancing..

You will be hard pressed to find I joints made in the USA, I think.

 

[Mbrooks420]

if you can do brakes you can do the u-joints harbor freight has a ball joint tool that pushes u-joints out fairly easy, if you have a 12 point 1/2 inch socket the drive shaft comes out in about 15 mins after you have all 4 wheels off the ground if you have 4x4...you will need to rotate the shaft...

It honestly probably could use both. If you can do brakes, you can do a u joint. Easy ramp job. Rent a press. Or, have a BFH.

 

[07gtman]

If you can get under the truck put the truck in neutral and push up and down on the drive shaft and side to side to see if there is play at the u-joint

 

[t99eddieb]

Thank you, fellow Explorerites!!
I knew this is something I can do on my own. Most people are telling me to take this to a shop and I need a lift... I will probably buy all the new parts myself and install since they are so cheap. Cheaper than any estimate a mechanic has given me thus far over the phone...

 

[Mbrooks420]

Easy jack stand repair. Surely no lift required.

 

[t99eddieb]

Thanks again, guys.. I will be ordering some heavy-duty non-greasable spicer u joints from amazon after I do the inspection this weekend. I miss driving my truck!!

 

[Mbrooks420]

Nothing wrong with grease-able joints. They will handle less shear torque, perhaps, but your explorer will never come close to physically breaking a u joint.

 

[Littleant]

Sound a bad u joint will make is a click/squeak when accelerating from a stop. Also a vibration at road speeds.

 

[t99eddieb]

Yes, vibrations at over 18k rpm and on gas between 15-50mph... But coasting the car in neutral it is smooth as glass. It's very scary shifting the car from drive to neutral while in motion... I'm always afraid I'll hit reverse. Two shops assured me the wheel and shaft bearings along with motor mounts have no issues. Not sure why he check my motor mounts? I also have new tires and alignment done recently.

 

[Mbrooks420]

He checked the motor mounts because they can cause vibration issues.

u joints are as cheap as it gets. Start there and move on if it still persists. At this age it’s almost certainly not in the best shape.

 

[t99eddieb]

So SAD. they don't make trucks like they use to anymore. mostly big plastic station wagons full of electrical issues advising you to "Phone Home" to the mother Stealerships... ;(

 

[Mbrooks420]

.......because of a u joint? Funny, in my old school full size trucks I can remember changing out u joints all the damn time.