Zf6 synchros

Farmer Rock

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This is kind of a stupid question, but I've always been curious if you could delete synchronizers to have an unsynchronized transmission? Double clutching doesn't help, shifting without the clutch does, so I would rather float the gears if it's not hurting the synchros. Then again, it would be a lot easier to float without them.


Rock
 

Booyah45828

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Yes and no.

Certain transmissions(toploaders, muncies, tremecs, etc) you can "faceplate", which replaces the synchronizers on the gears with a dog clutch setup, making it unsychrnoized like you're after. They do it in racing transmissions where synchronizers aren't necessary, but reliable shifts are. I don't think I've heard of a zf ever being faceplated, but who knows. It's not cheap to have a transmission faceplated, so I doubt it'd be worth it.
 

greenskeeper

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This is kind of a stupid question, but I've always been curious if you could delete synchronizers to have an unsynchronized transmission? Double clutching doesn't help, shifting without the clutch does, so I would rather float the gears if it's not hurting the synchros. Then again, it would be a lot easier to float without them.


Rock
Bent clutch fork? Original master/slave assembly?

First step would be to replace the fluid with pennzoil synchromesh, filling through the shifter is the easiest method.

Next you could remove the slave cylinder and measure the distance from the housing to the shift fork.

The heim joint mod can also alleviate poor shifting issues.
 

Farmer Rock

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Bent clutch fork? Original master/slave assembly?

First step would be to replace the fluid with pennzoil synchromesh, filling through the shifter is the easiest method.

Next you could remove the slave cylinder and measure the distance from the housing to the shift fork.

The heim joint mod can also alleviate poor shifting issues.
I assume the clutch hydraulics are original, but not certain. The clutch grabs really low, the pedal is extremely stiff/hard, and it feels like it is not disengaging completely. Getting it in L or R is a chore, and it seems to be worse when hot, which points towards the clutch I guess.
It almost feels like a few fingers on the pressure plate are bent.
It's just a pain all around.
I really need to fix this, but I don't have time to drop the trans right now.
Also, is shifting without the clutch hurting the synchros? I can't find a straight answer. It shifts way smoother that way.


Rock
 

greenskeeper

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I assume the clutch hydraulics are original, but not certain. The clutch grabs really low, the pedal is extremely stiff/hard, and it feels like it is not disengaging completely. Getting it in L or R is a chore, and it seems to be worse when hot, which points towards the clutch I guess.
It almost feels like a few fingers on the pressure plate are bent.
It's just a pain all around.
I really need to fix this, but I don't have time to drop the trans right now.
Also, is shifting without the clutch hurting the synchros? I can't find a straight answer. It shifts way smoother that way.


Rock
It would take 5 minutes to look under the dash at the clutch pedal to see if the rod/linkage is worn, and also to remove the slave cylinder (twists off) and measure the distance of the clutch fork.

Shifting without a clutch is harder on the transmission, but if you have to do it just to get by until you fix the issue you'll be ok.
 

catbird7

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I have a complete ZF6spd with manually shifted transfer case, factory flywheel, clutch disc and pressure plate. The truck had 128,000 miles. When I bought it from original owner he told me it popped out of reverse occasionally. I never drove truck other than moving around in driveway. Therefore I can't confirm or deny how it works. If you're interested in buying a trans to rebuild while still driving your truck, send me a pm.
 
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