Blue/Black ZF6 labels

[Perry Mitchell]

Can somebody explain the differences between blue and black ZF6 speed transmission labels? Which is better or more desirable? I have a 91 ZR1 transmission with black label that was removed from a totaled Z with 17,000 miles complete with bell housing, flywheel, and dual mass clutch sitting on my shelf. Not sure if I will use it in a future project or not. What is the value of this unit?

[Corvettes White]

Not sure of any differences. Blue were built in the US. Black in West Germany before the wall fell.

I would keep the black one just because it makes a story more nuanced.

George

[secondchance]

My understanding is the early Zs' black label ZF6s have higher torque rating but some of these transmissions (if not all) can be noisy at low speed. Later blue label ZF6s are quieter. I do not know when the change occurred (perhaps concurrent with 375hp to 405hp in 93?).
My 91 had a black label and 94 has a blue label.

[Thomas ZR-1]

Picture from Bill`s homepage zfdoc.

Black label: 89-92 610 Nm max
Blue label: 93-95 540 Nm max

[wfot]

The black tags have the gear/dogs welded together, making them stronger. the blue tags have pressed on dogs, still very strong. also yes the tooth angel of the blue tags are different, making them a little quieter..

John

[secondchance]

Also, later blue tag throwout bearings have nylon sleeve whereas early black tag throwout bearings do not. This may be a contributing factor for later ZF6 being quieter.

[tccrab]

Don't forget that late model blue label have no reverse lockout ring on shifter, the have "crash through" reverse engagement.

Crabs

[Perry Mitchell]

Thank you all for the replies. So it seems there isn?t much difference in the two labels other than year specific. Possibly the black label is more desirable. Any ideas on the value of my transmission with shifter, bell housing, flywheel, and clutch assembly with only 17,000 miles of use?

[Dynomite]

1. Throwout Bearings.

I have a 91' ZF S6-40 Transmission (Black Label) Parts List No 1052-000-035 with a collar diameter of 1.373 inches and a 94'-95' ZF S6-40 Transmission (Blue Label) Parts List No 1052-000-087 with a collar diameter of 1.305 inches.

Post 38 - Throwout Bearings and Clutch Forks

Post 241 - Rebuilt Black Label Transmission Installed and New Driveshaft U-Joints

[5ABI VT]

Black = made in Germany
Blue = made in USA

early to 93 have a different input shaft diameter as well as the higher torque rating and associated differences. my 94 is an early car and has a black tag that has a later 'revised' 94-96 internals