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'85 F350 6.9L IDI rattle/vibration

2K views 9 replies 4 participants last post by  Fockertaint 
#1 ·
Thanks for the place to post and to all who read and reply. New to the diesel engine. Have a 6.9 4 speed manual. Strange rattle/vibration trying to keep rpms low on the gravel road home. Switching between 1st, 2nd help a lot or pressing clutch and just rolling. Any ideas of this sound. This is the only words I can think to describe.
 
#2 ·
More than likely the springs are broke on the clutch and rattling around. It needs attention soon if that's the case, it could cause a catastrophic failure.
 
#3 ·
Actually broken springs would be louder with the clutch pedal depressed. Wise thing would be to go by a trans shop and have them go for a test drive for a more accurate diagnosis. Too many variables to diagnose with just a computer screen to stare at.
 
#5 ·
That's very true, it's called gear rollover noise. The original dual mass flywheels cancel out the rollover noise. And when you depress the clutch pedal you are cancelling out the engine firing spikes which causes the noise.
 
#7 ·
You're welcome Many people have changed them over to a single regular type flywheel, there's pros and cons to that deal. As far as removing the bottom clutch cover to inspect, I can't say. On my '91 there's a lip on the forward edge of the cover and it's trapped under the rear edge of the oil pan (IIRC) so mine won't come off. Don't know if that was a screwup on the assembly line or what, most all covers can be removed. I tried many years back when I wanted to lube the T.O. bearing collar where it slides on the input shaft bearing retainer sleeve. I'm still on my original clutch so I've never pulled the trans or clutch assembly.
 
#8 ·
On my '91 there's a lip on the forward edge of the cover and it's trapped under the rear edge of the oil pan (IIRC) so mine won't come off. Don't know if that was a screwup on the assembly line or what, most all covers can be removed. I tried many years back when I wanted to lube the T.O. bearing collar where it slides on the input shaft bearing retainer sleeve.
Hijack alert.... Unless there's something specific about that generation, that shouldn't be. The ZF5s behind the OBS PSDs (the same tranny, if I'm not mistaken) had that lip/flange on the cover, and there was actually a TSB about it touching the back surface of the oil pan and "sawing" a groove/slot in the pan over time. They issued a new cover without that flange, but I just cut mine off. But I was able to remove the cover with the engine and tranny in place. Did you try pressing backward on the cover to see if that would allow it to clear the pan? Are you sure it wasn't hanging up on something else?
 
#9 · (Edited)
Did you try pressing backward on the cover to see if that would allow it to clear the pan?
Oh yeah, it was important to remove it so I could lube the collar like I said. My other option is going in through the clutch fork hole in the bellhousing every few years and lubing it that way which is a major pain. I'd have to get under it again, unbolt it to verify positively it's trapped by the pan, that's why I added IIRC (if I recall correctly). Bought the pickup new and it's been years since I tried to remove the cover. In later years back then Ford came out with a TSB stating there was an improved collar with a wiper on it which eliminated the problem.
 
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