Early VS old T/O bearing on the ZF tranny

[devilfish]

Early VS newer T/O bearing on the ZF tranny

I have heard that there is supposed to be diffrent kind of T/O bearing for the ZF 6 spd.
89-93 the inpushaft is thicker on the ZF and requier a T/O bearing with a wider inner diameter.
And 93-96 has a "thinner" inputshaft and uses a T/O bearing with a thinner inner dimater?

Is this true?

Thanks ;help

 

[petroszz4]

When i changed my clutch i had the wrong bearing.After installation, while bleeding the slave cylinder the pedal felt a little tight.Stepped on it a little harder and bent the fork and busted the slave cylinder.The bearing that i had was not the one for the 1989 vette and got stuck on the tranny shaft.

 

[BigRed]

I have heard that there are two generations of ZF-6's so this could be very true.

I think the idea was to beef up the trans for the later ZR1's and LT4's

 

[petroszz4]

I did some research and it seems like the early ZF's are stronger than the late ones

 

[Rob]

In 1993, changes were made to the ZF 6-speed transmission in order to reduce gear whine which was a common complaint among Corvette customers.

The whine was due to the shape of the gear teeth (helical cut) which is what contributed to the high torque capacity of the ZF.

In 1993, the part number for the ZF changed from 10186865 to 10255122. In the second generation ZF, the gear ratios stayed the same, but there was an increase in helical pitch of all the drive gear teeth which helped to reduce the whine. The 2nd, 3rd, 5th and 6th speed gears also went to a crimped spline-fit method of fastening the synchronizer clutch body to these speed gears.

As a result of these changes, the second generation ZF had a lower torque capacity than the first generation, but I don't currently have these numbers available at this time.

 

[Topless]

How likely is it for a throw out bearing to go before the clutch?

What would be the signs?

Thanks.

 

[petroszz4]

From my experience when the bearing is starting to go bad it will start ticking or knocking in neutral with the clutch pedal released.When you depress the clutch pedal the noise will go away.

 

[Rob]

When the throw out bearing starts to go, it will howl when you let the clutch pedal in and out and will happen at any point during the clutch pedal stroke.

It is most prominently heard when either the clutch is very cold or very hot.

 

[Topless]

Rob-
Thanks... I will keep track of when it does it a little better. Do you think a weak clutch master cylinder might be accelerate this problem? Sometimes I have to double clutch to get it into gear. (Usually 1st and 3rd)

 

[Rob]

Rob-
Thanks... I will keep track of when it does it a little better. Do you think a weak clutch master cylinder might be accelerate this problem? Sometimes I have to double clutch to get it into gear. (Usually 1st and 3rd)

I believe that it would. Check out the FAQ section at http://www.zrdoc.com

 

[Topless]

Thanks...I will do that.
I think that is my next project.