ZF5 LEAK FROM TOP

NeverHave-I-Ether

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Went to put out my fluid in the top of trans today. As is often the case, when I went to pull the top 4 bolts out the Allen heads stripped. Yes, I used the correct size and spun it the loosey direction. Damn this is annoying.

Never-Have-I-Ether
 

Big Bart

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Went to put out my fluid in the top of trans today. As is often the case, when I went to pull the top 4 bolts out the Allen heads stripped. Yes, I used the correct size and spun it the loosey direction. Damn this is annoying.

Never-Have-I-Ether
Sorry to hear that, some days you kick butt some days you get your butt kicked.

Can you grab the heads with a good pair of vise grips?
 

NeverHave-I-Ether

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Sorry to hear that, some days you kick butt some days you get your butt kicked.

Can you grab the heads with a good pair of vise grips?
I may try, I used a funnel and did it like last time. Completely changed the fluid so it's nice and fresh. The synchros seem to be damaged and won't let me downshift. It does grind if I try to force it. Luckily it's only above 20mph so not a huge impairment.

As for them screws, my wrench was bending, thats how tight they were. I'm going to ask a friend to weld some nuts on the top, I suspect though that the bolts will break off before the screw twists.

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Nero

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Something I've done on very stuck Allen bolts that usually works, get a small chisel or punch, and shock it a few times with a hammer. Usually the vibration causes them to loosen up, or break away any crud buildup then they should come out with an Allen key.
 

sjwelds

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Welding a nut on should work, as the heat from welding should help loosen the bolt. A tip an old guy taught me is to work it looser a bit, then tighter, then loosen, etc, until things free up.
 

Old Goat

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What worked for me with those Allen head or hex head bolts.
I was pulling a 4-spd trans and Clutch to get a rare 38# 300D Mercedes FW that was in PNP.
I was taking off the pressure Plate and last bolt was stripped out.

I picked up a set of 4, of these 12 pt metric bits. 12 down to a 6mm.
I used the 6mm and drove it into the hex head and it came right out.
YMMV but it worked for me.

That was steel on steel, but a steel bolt in an Aluminum case there can be a bit more rust/corrosion .
I have had them twist off in aluminum before.


Goat
 

ROCK HARVEY

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That’s a pain, sorry to hear about the bolt stripping. If one or two do end up breaking off, I would just silicone it all up and deal with it properly when you eventually drop the trans to deal with the synchros. You could also take off all the 13mm bolts that attach that little shifter housing to the bellhousing, then take the shift housing out of the truck to drill out the broken bolts.
 

ROCK HARVEY

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Well Ether I guess those bolts are just made of soft metal! I stripped 2 of mine as well taking the cover off. I had an easier time though since my transmission is already out of the truck. If you end up buying new ones they are metric, size M6-1.00 x 16mm.
 

papadiesel

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Make sure the vent is not plugged, it will force fluid past the boot when building heat.
Yes the ZF-5 should have a vent up near the top of the case.

On the ZF-6 it's just forward of the shift tower - a fitting that has a loose fitting cap over it.
 

ROCK HARVEY

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We’ll you’ve helped me discover something interesting. I have two ZF5s in my garage, and I looked all over them and couldn’t find a vent. Then I did some internet digging and it turns out the zf5 vent is in the stub boot! It’s a little half-moon cutout, I took a picture below:
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The problem is that the new aftermarket stub bolts don’t have the vent. I looked between all the folds of the one I just installed and couldn’t find it. That means I need to add a vent somehow. I sure wish I would have learned this when I had it all open and apart! I could have easily drilled and tapped the case to add a vent. Maybe I’ll just make a little cutout in the boot like what came stock on the truck.
 

papadiesel

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Many zf5 that I’ve worked on in the past have had the button style bent looks like a bolt with a little mushroom top
 

ROCK HARVEY

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Maybe the s5-47s have the vent in the bellhousing. I would definitely prefer that system to a “vent” in the stub boot.
 
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