96 7.3

OBS-Addiction97 · Nov 24, 2018

I just picked up a 96 F350 4x4 dually for a work truck. One owner with 145,000 miles. The truck has a zf5. I noticed it has a pretty loud rattle / vibration that starts around 2300 rpm. It happens it neutral or driving. P/o said he replaced the clutch. Any ideas? My thoughts are it’s something to do with the clutch, maybe a broken spring or out of balance.

79jasper · Nov 24, 2018

Well, does it do it with the clutch depressed?

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OBS-Addiction97 · Nov 24, 2018

79jasper said:
Well, does it do it with the clutch depressed?

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Yes, it still does it with the clutch depressed.

79jasper · Nov 25, 2018

Double check to make sure the exhaust isn't touching anywhere. The downpipe likes to rub the firewall on some trucks.
Though you could be correct on the clutch. Could also have the dual mass flywheel.

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OBS-Addiction97 · Nov 25, 2018

79jasper said:
Double check to make sure the exhaust isn't touching anywhere. The downpipe likes to rub the firewall on some trucks.
Though you could be correct on the clutch. Could also have the dual mass flywheel.

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I cut the factory exhaust off yesterday, alothough the truck has an aftermarket 3” down pipe. I will double check clearance on the firewall.

On a different note the trans will grind into 3rd unless I let the Rpms drop back down to an idle and also while downshifting into second. To me something seems off with the clutch or somewhere related, still.

Magnum PD · Nov 25, 2018

You could take the access cover off the trans and make sure the flywheel is running true and see if you could tell if the noise is coming from there.

m_j · Nov 30, 2018

synchros are dead, try matching rpms like a trucker

superpsd · Dec 1, 2018

3rd gear worn syncro grinding due to high mileage on the ZF are common. Mine grinds sometimes when cold Redline MTL helped cut down the grinding.

m_j · Dec 1, 2018

is it dual mass flywheel or the single?

OBS-Addiction97 · Dec 2, 2018

m_j said:
is it dual mass flywheel or the single?

Haven’t had time to look. My guess is a single with how it drives, but I could be wrong.

I’ve put a few hundred miles on the truck. No real changes to speak of besides figuring out how to shift the trans with out grinding.

OBS-Addiction97 · Dec 2, 2018

superpsd said:
3rd gear worn syncro grinding due to high mileage on the ZF are common. Mine grinds sometimes when cold Redline MTL helped cut down the grinding.

The truck only has 146k on it, no sure what constitutes high mileage for a zf. I have some LE fluid I’m going to put in to see if it helps any with the grinding.

I’d like to eventually put an auto in it and sell this manual as a package deal.

m_j · Dec 2, 2018

the rattle can be a single mass symptom

OBS-Addiction97 · Dec 3, 2018

Well, leaving my house this morning the clutch pedal went to the floor and stayed there. I haven’t had time to look into the issue.

CTFFEMT · Jan 7, 2019

slave cylinder went out. Not hard to replace.

OBS-Addiction97 · Jan 8, 2019

CTFFEMT said:
slave cylinder went out. Not hard to replace.

Ended up being the plastic budging. I replaced it with a heim joint.

OBS-Addiction97 · Jan 16, 2019

Ended up replacing the fuel pump, truck runs better.

I’m still having an issue where the truck developes a slight miss at operating tempature. It runs perfectly when it’s cold. Not sure if it’s hpo related since it’s only happening when warm.

JCart · Jan 17, 2019

OBS-Addiction97 said:
Ended up replacing the fuel pump, truck runs better.

I’m still having an issue where the truck developes a slight miss at operating tempature. It runs perfectly when it’s cold. Not sure if it’s hpo related since it’s only happening when warm.

Might be time for new o rings on the IPR, think Riff Raff has a Kit. Typically when they go it’s a hard start when warm and fires up fine when cold as the oil is thicker when cold.

For failing synchroes try filling tranny with Redline MTF, made a significant improvement on my ZFs and that is all I’ll run in them.
Cheers,
j

OBS-Addiction97 · Jan 17, 2019

JCart said:
Might be time for new o rings on the IPR, think Riff Raff has a Kit. Typically when they go it’s a hard start when warm and fires up fine when cold as the oil is thicker when cold.

For failing synchroes try filling tranny with Redline MTF, made a significant improvement on my ZFs and that is all I’ll run in them.
Cheers,
j

What’s the part number for the mtf? All that came up on google was MTL.

Thanks