ZF, TOB or something else?

Kizer

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Gentlemen,

The latest addition to my remuda (no history but someone has pulled the tranny at least once) is "rattling"
when I release the clutch ... only in reverse. I don't "feel" it in the pedal.

I'm having trouble understanding what could make noise "only in reverse".

Ideas?

Thank you,
Kizer
 

onetonjohn

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You don't "feel" the clutch engage as you let off pedal? Truck doesn't move in reverse? Transmission shop would likely tell you it's "internal" and they need to tear it down to know for sure. Usually noises are bearings, but rattle sounds like gear or something rubbing against a gear. Is this 4 or 5 speed?
 

onetonjohn

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Rattle go away when you press in the clutch? Does it only make the noise as it is engaging? Or does it still make the noise when clutch is all the way out (in reverse).
 

Kizer

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Rattle go away when you press in the clutch? Does it only make the noise as it is engaging? Or does it still make the noise when clutch is all the way out (in reverse).

It doesn't rattle until I begin to release the pedal with the trans in reverse. Once I've built momentum, everything is "as normal"
 

Kizer

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Driving this morning, next to Jersey barrier, I down shifted ... was able to hear the same rattle echo off of the barrier. It doesn't make noise when I let off the throttle, just when I down shift or take off in reverse ... sounds "rotational", if that makes sense. Almost the same rattle that you get with a busted DMF but not consistent and not in neutral ...
I guess it's time for a tutorial on the inner workings of the ZF5.
 

renjaminfrankln

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Driving this morning, next to Jersey barrier, I down shifted ... was able to hear the same rattle echo off of the barrier. It doesn't make noise when I let off the throttle, just when I down shift or take off in reverse ... sounds "rotational", if that makes sense. Almost the same rattle that you get with a busted DMF but not consistent and not in neutral ...
I guess it's time for a tutorial on the inner workings of the ZF5.


Mine did the same thing. Turbo pipes contacting cab.

Accelerating torques your engine/transmission one way and nothing contacts. Decelerating (or accel in reverse) torques it the other way. Give it enough torque and you get metal/metal contact. Downshifting or letting the clutch out in reverse twists the engine up enough that you get contact.

When I first got my truck back from having the flywheel done, the shop bumped the turbo pipes and I was getting contact when just letting off the throttle. Tweaked it some, now it only does it when I let the clutch out in reverse backing up a slight incline (if i'm gentle with it on flat ground I can get going without the noise).

Replacing your worn front cab mounts will probably give you enough clearance to make the noise go away. I need to do mine.
 

Kizer

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Can anyone confirm Kevlar pilot bushing part #:
South Bend Clutch PB50KHD


Any advice on a good TOB would be appreciated. The one that LUK sends sure feels cheap. I havn't had a problem with one yet ... sure looks like the weak point.
 

IDIoit

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this cured mine

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