ZF5 LEAK FROM TOP

NeverHave-I-Ether

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Howdy y'all!

As per title, my transmission is leaking from up top some where. It comes down the passager side. Started shifting hard so I'm changing the fluid today with Motorcraft Mercon V. I'd rather use Redline MT-90 but not going to put expensive **** in the trans just for it too leak out..... Is it possible it's leaking from the shifter itself? Its wet all around with trans fluid, or can it be coming from further up and wind is blowing it there? Picture attached.

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NeverHave-I-Ether

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Quite filthy and seems likely this is the source of leak. When I pour the ATF in, can I pour it right into this hole? Or do I need to pull something else off to fill it from the top?



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Anyone have part numbers? These are nasty and broken, do these hold transmission fluid? Never-Have-I-Ether
 

Jesus Freak

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If you pour the fluid down the top like that, it seems to me that youll be washing dust and grime into the tranny case. I don't have part #s but I would recommend replacing the shifter bushings while you're that far in. I'm sure that's your "leak" though, there's no pump just spinning gears that sling fluid around.
 

NeverHave-I-Ether

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If you pour the fluid down the top like that, it seems to me that youll be washing dust and grime into the tranny case. I don't have part #s but I would recommend replacing the shifter bushings while you're that far in. I'm sure that's your "leak" though, there's no pump just spinning gears that sling fluid around.

I'll definitely be wiping it clean before sealing it up. Found the part on eBay. It's called a rubber inner boot.

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ROCK HARVEY

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Yup that torn stub boot is the source of your leak. It’s $20 on ammazon. Allstate gear has a whole shifter rebuild kit with the plastic shift bushings, gaskets, and that boot for $30. I just ordered the kit, here’s the link:

 

NeverHave-I-Ether

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Yup that torn stub boot is the source of your leak. It’s $20 on ammazon. Allstate gear has a whole shifter rebuild kit with the plastic shift bushings, gaskets, and that boot for $30. I just ordered the kit, here’s the link:

Thanks!
Where are the gaskets used?

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ROCK HARVEY

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You’ll probably only be concerned with the small oval one, it goes under the metal plate/top cover that the stub boot attaches to (the one covered with grime in your picture). The medium gasket goes between the shifter housing and the bellhousing, and the two big ones are for your PTO covers. IIRC the metal plate takes a 5mm Allen to remove the 4 screws.
 

IDIBRONCO

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If you have the shifter removed, then you can add the ATF through that hole. It's a lot easier and less messy doing it that way.
 

NeverHave-I-Ether

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If you have the shifter removed, then you can add the ATF through that hole. It's a lot easier and less messy doing it that way.
I just added a quart from the top without removing it. There IS GRIME inside it unfortunately, and I'm worried how much is in the transmission already.

So, I added a quart because I know I'm low to play it safe. Then I'm ordering a shift boot kit and will replace the bushings and grommet while I'm at it. Then I'll change the transmission fluid and hope that most of the dirt is out. I put cling wrap around the old rubber to keep dirt out for the next several days.

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NeverHave-I-Ether

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Took for a test drive, drove good and shifted very smoothly. On my way into the drive way though it absolutely refused to go in 1st/2nd gear. As soon as I parked and turned engine off it went into gear. Well...... tomorrow I drive to work and can experiment more. This sure is annoying.

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Big Bart

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These damn Fords, barely out of warranty and they won’t shift worth a damn! :p

Likely you shook or washed some dirt in to the shift mechanism, it should wash down to the bottom after a few miles. When you put in the new boot and shift kit you should be golden.
 

NeverHave-I-Ether

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Here's my update from the 40 mile work commute.

Everything upshifts good. When downshifting I cannot go into second gear going over 20mph. Soon as I'm at 20mph I can downshift

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Big Bart

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NeverHave,

You mentioned you had a shift issue before looking at the shift boot. That you now put some Motorcraft ATF in to fill it up till you fix it.

Somethoughts -

The clutch has a lot to do with shifts.
The syncro’s have a lot to do with the shifts.
The type of ATF you use has a lot to do with the shifts. (Mixing brands and types could help or hurt.) More so on these trucks than most, members have found certain ATF’s to give better shifting.

Suggestions
1) Fix the boot and shifter bushings, take that out of the equation. That is not likely causing the downshift issue.
2) Replace the tranny fluid and see where you are at. Perhaps you are happy or good enough for government work.
3) If still not happy you may need a new clutch, clutch master or slave, or néw syncro’s.

Syncro’s are usually pretty obvious as generally only one or two gears grinds frequently or most every time. Do the clutch, pressure plate, and throwout bearing if you do the syncro’s as the tranny is already out. Also do the rear main seal! Redoing it all 5k, 10k, or 20k latter is going to suck!

Attach some more pics and let us know what you find.
 
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ROCK HARVEY

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One other thing I would check is the bushings in your pedal assembly, including the little plastic clutch lever bushing if you haven’t done the heim joint mod. I’d hate for you to pull the tranny only to find that you weren’t getting full clutch disengagement due to worn bushings.
 
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