Transmission or flywheel noise?

[alexl]

Hey everyone,

I purchases a 1987 F250 that a PO has replaced the 6.9 with a 7.3 (unknown year). I get some pretty nasty noise (gravel in a coffee can) in all gears (ZF5), and to a lesser extent, sometimes in neutral with the clutch engaged, but not always. Press in the clutch and the noise goes away for the most part. My first inclination was input shaft bearings in the transmisison, but as i do some research of my own i am starting to lean towards a failing dual mass flywheel and/or pilot bearing. For those who have had flywheel issues, do my symptoms point to flywheel problems, or would you guess transmission problems? There is also a very brief but pronounced rattle at engine shutdown.. im not sure if this is inherent or another sign pointing to the flywheel? I realize that the ZF5 is a noisy transmisison, i am not concerned with the whine at all, just the nasty noise.

Kind Regards,
Alex

 

[franklin2]

You may not even have the original dual mass flywheel, you need to take the inspection cover off and check. You may have a solid flywheel conversion and if that is the case, then believe it or not all that noise is probably normal. That's the reason the factory ran the dual mass flywheel, to get rid of all that noise.

Check and see what type of flywheel you have.

 

[alexl]

thanks for the info.. If that is the case then i will just plan on installing some insulation on the floorboards when i replace the carpet

 

[pelky350]

When my dual mass went bad I noticed a rattle when it would shut off every time, try shutting it off with the clutch engaged and see if the rattle is gone that will point to the dual mass having broken springs/warn springs in it. I believe if you take inspection cover off and have someone engage the clutch for you you can check the flywheel for play by moving it back and forth if it moves it's allowed something like 3/4 inches movement to pass the test there should be a write up on it somewhere on ere to diagnose dual mass problems

 

[79jasper]

Sounds to me like failing DMF.

Sent from my SAMSUNG-SM-G935A using Tapatalk

 

[alexl]

update.. The same noise exists, although slightly less pronounced when the clutch is in and coasting in gear. I'm starting to thing it is a transmission problem.. would a pilot bearing exhibit this?

 

[alexl]

just got back from another test drive. Truck makes the same noise in every gear, and in neutral with clutch pedal depressed and coasting. Because of this, i don't think this is an issue with the input shaft... as it should be disengaged in neutral and the noise continues. it also makes the same noise with power on in gear, not just coasting.. so i don't really think that it is a gear rollover noise. My best guess at this point is jackshaft bearings. May be time to drop the transmission and replace or rebuild.

Alex

 

[franklin2]

Why don't you crawl underneath and take a look at the flywheel? If you have the DMF you can check it for play. You can also see if you even have a dmf.

 

[alexl]

Why don't you crawl underneath and take a look at the flywheel? If you have the DMF you can check it for play. You can also see if you even have a dmf.

I had my wife depress the clutch while I was under the truck. I couldn't get the flywheel to move at all. It looks like a dual mass to me, but seams pretty solid. If it is a dual mass then I will likely replace it when I remove the transmission. I dismissed the dmf for the offending noise because I get the same noise no matter what the condition, so long as the truck is rolling. In any gear, neutral, power on or coasting, clutch in or clutch out. This is how I arrived at the conclusion that the transmission has bearing(s) in poor condition. Transmission still shifts fine so I think I will leave the synchro's and just replace the roller bearings and seals. The rear seal looks to be leaking fluid quite aggressively as well. Shouldn't need anything but a standard bearing puller to do a bearing job.