Drive train experts...please step inside!

unclehoser

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Crazy problem. My 2002 F250 Powerstroke with ZF6 tranny is experiencing a "vibration" or "rumble" at low RPMs. Seems to be most noticeable between 1000-1500 RPM, and is directly associated with RPM, as opposed to speed. Also seems to be worse when not under load, such as after a downshift or letting off the throttle.

This problem has disappeared and reappeared twice, for no apparent reason. My original thought was possibly a carrier bearing or u-joint failure, but that would seem to change the "frequency" of the rumble with speed, rather than RPM.

When clutch is disengaged or tranny is in neutral and free-wheeling, everything's smooth as it should be. I'm thinking it's some kind of clutch issue...any thoughts???

Thanks in advance-
Dave
 

lotzagoodstuff

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Input shaft or bearing on the trans? Here's another thought: have you checked the big bolt that holds your pinion gear in place?

I would take your truck to a trans/driveline place and have them take a look. The guys who know that stuff really can find a bad u joint or driveline related problem better than the rest of us.

Good luck
 

u2slow

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The input gear and
Crazy problem. My 2002 F250 Powerstroke with ZF6 tranny is experiencing a "vibration" or "rumble" at low RPMs. Seems to be most noticeable between 1000-1500 RPM, and is directly associated with RPM, as opposed to speed. Also seems to be worse when not under load, such as after a downshift or letting off the throttle.

This problem has disappeared and reappeared twice, for no apparent reason. My original thought was possibly a carrier bearing or u-joint failure, but that would seem to change the "frequency" of the rumble with speed, rather than RPM.

When clutch is disengaged or tranny is in neutral and free-wheeling, everything's smooth as it should be. I'm thinking it's some kind of clutch issue...any thoughts???

How many miles?

On decel/downshift the thrust direction changes in the gearbox. I had one 5spd than you could feel the guts shift fore/aft in the stick when you were on/off the skinny pedal.

I'm leaning toward input and/or countershaft bearings. They're always turning proportionate to engine speed so long as the clutch is engaged.
 

greenskeeper

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Crazy problem. My 2002 F250 Powerstroke with ZF6 tranny is experiencing a "vibration" or "rumble" at low RPMs. Seems to be most noticeable between 1000-1500 RPM, and is directly associated with RPM, as opposed to speed. Also seems to be worse when not under load, such as after a downshift or letting off the throttle.

This problem has disappeared and reappeared twice, for no apparent reason. My original thought was possibly a carrier bearing or u-joint failure, but that would seem to change the "frequency" of the rumble with speed, rather than RPM.

When clutch is disengaged or tranny is in neutral and free-wheeling, everything's smooth as it should be. I'm thinking it's some kind of clutch issue...any thoughts???

Thanks in advance-
Dave

original clutch?

dual mass flywheel could be on it's way out
 

unclehoser

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Input shaft or bearing on the trans? Here's another thought: have you checked the big bolt that holds your pinion gear in place?

I would take your truck to a trans/driveline place and have them take a look. The guys who know that stuff really can find a bad u joint or driveline related problem better than the rest of us.

Good luck

I wish it was that simple. There's not much for specialty shops in this little spot on the map! If I could travel and wait, I guess I could head to the 'big city'. I'm 4 hours West of Phoenix, 5 hours East of LA, and 2 hours south of Vegas.

I'm really hoping that it's something as simple as a clutch...and less expensive than a tranny rebuild.
 

unclehoser

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original clutch?

dual mass flywheel could be on it's way out


Don't know if it's the original clutch. I bought the truck with 214K on the odometer, and I have about 240K on it now. I guess the only way to know for sure is to have someone tear it apart and inspect stuff.

I really don't understand the terminology, though. I've seen 'dual mass' flywheels mentioned, but I have no idea what that means!
 

unclehoser

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The input gear and


How many miles?

On decel/downshift the thrust direction changes in the gearbox. I had one 5spd than you could feel the guts shift fore/aft in the stick when you were on/off the skinny pedal.

I'm leaning toward input and/or countershaft bearings. They're always turning proportionate to engine speed so long as the clutch is engaged.


I haven't noticed anything like that going on, but I'll check it out on my next drive! Sounds like a good diagnostic approach.
 

Philip1

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Don't know if it's the original clutch. I bought the truck with 214K on the odometer, and I have about 240K on it now. I guess the only way to know for sure is to have someone tear it apart and inspect stuff.

I really don't understand the terminology, though. I've seen 'dual mass' flywheels mentioned, but I have no idea what that means!
dual mass flywheels, simply put, have 2 flywheels in 1 that are connected together with springs and bearings. that way the flywheel can act as a shock absorber for the energy pulses the engine produces creating a smoother transfer of power into the transmission
 

greenskeeper

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Don't know if it's the original clutch. I bought the truck with 214K on the odometer, and I have about 240K on it now. I guess the only way to know for sure is to have someone tear it apart and inspect stuff.

I really don't understand the terminology, though. I've seen 'dual mass' flywheels mentioned, but I have no idea what that means!

Can you post a video of the problem?

If it's the dual mass flywheel and it fails catastrophically it can take out the bellhousing or crack the transmission case.
 

unclehoser

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dual mass flywheels, simply put, have 2 flywheels in 1 that are connected together with springs and bearings. that way the flywheel can act as a shock absorber for the energy pulses the engine produces creating a smoother transfer of power into the transmission

Thanks! Learn something every day...
 

unclehoser

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Can you post a video of the problem?

If it's the dual mass flywheel and it fails catastrophically it can take out the bellhousing or crack the transmission case.
Can you post a video of the problem?

If it's the dual mass flywheel and it fails catastrophically it can take out the bellhousing or crack the transmission case.


There's nothing to video, sadly. It's a rumble, a vibration, that I can feel. It's reminiscent of a failed u-joint or carrier bearing, but stops completely when the clutch is disengaged or the trans is in neutral. My first reaction was 'u-joint', but that should be apparent any time the drive shaft is turning, correct?
 

79jasper

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Not always.
To check the flywheel (trans in neutral) use a screwdriver or prybar to try turning the flywheel and pressure plate individually.

Sent from my SM-G988U using Tapatalk
 

greenskeeper

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There's nothing to video, sadly. It's a rumble, a vibration, that I can feel. It's reminiscent of a failed u-joint or carrier bearing, but stops completely when the clutch is disengaged or the trans is in neutral. My first reaction was 'u-joint', but that should be apparent any time the drive shaft is turning, correct?

pull the transmission and inspect the clutch/flywheel. You've got a 2wd truck so it's pretty easy even if you leave the truck on the ground.
 

greenskeeper

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Not always.
To check the flywheel (trans in neutral) use a screwdriver or prybar to try turning the flywheel and pressure plate individually.

Sent from my SM-G988U using Tapatalk

no inspection port on a SD truck
 

unclehoser

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pull the transmission and inspect the clutch/flywheel. You've got a 2wd truck so it's pretty easy even if you leave the truck on the ground.


The advice is good, as usual! I now have a better understanding of what could be malfunctioning. This problem, more than likely, will be left up to someone with the shop, the tools, the lift, etc....my back doesn't like being underneath vehicles, and this one is my main mode of transportation. I do have a 'spare' car to get back and forth to work for a while...just can't haul anything in it!

Hopefully, I'll find someone around here that has a clue, and relate to them everything I've found out here. It's definitely a great starting point.

As always, thanks so very much for your time and trouble. Without you guys on this forum I'd be completely lost!

Dave
 
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