Black or Blue ZF?
Racer
Joined: Mar 2016
Posts: 344
Likes: 65
From: Ontario, Canada
Black was the earlier one and was stronger than the Blue. As I understand it the black had straighter cut gears which made it stronger but was fairly noisy. The blue tag had more angle cut gears which made it quieter. I have a black tag in my 90 and I can definitely hear it whine while accelerating in first gear.
Team Owner
Joined: Oct 2004
Posts: 81,241
Likes: 3,063
From: altered state
St. Jude Donor '05
Thought it was 450 and 400 lbs something like that?
Its always more than GM recommends to be safe. Im a sucker for a loud manual trans, loved the whine.
Wish I could afford a gearset like that for a T56
Its always more than GM recommends to be safe. Im a sucker for a loud manual trans, loved the whine.
Wish I could afford a gearset like that for a T56
Le Mans Master
Joined: Jun 2009
Posts: 6,528
Likes: 752
From: South Dakota
Try looking at zfdoc.com for a lot of info.
The black tag was rated at 610 Nm torque capacity.
The blue tag was rated at 540 Nm torque capacity.
Like others stated the black tag has more straight cut gears than the blue tag and the black tag makes a little more noise.
The input shaft guide is a different diameter between early and late cars so they use a different throwout bearing that slides over it.
Not specific to black or blue, the blue has some differences. The '94 blue tag uses a lift ring for reverse lockout, but the '95 & '96 use a "crash through" design that does not use a lock ring but uses more effort to push through to reverse. The black tag has some differences too such as a different speed sensor in the early years.
In practice there is very little difference. Both are very strong and even behind high horsepower motors they last well. I have both black and blue ZF's and I don't notice the difference in noise.
Although I like the thought of a stronger transmission, I like the '95-'96 shifter. So for me it makes almost no difference and currently have one black tag and one blue tag and like both.
Good luck.
The black tag was rated at 610 Nm torque capacity.
The blue tag was rated at 540 Nm torque capacity.
Like others stated the black tag has more straight cut gears than the blue tag and the black tag makes a little more noise.
The input shaft guide is a different diameter between early and late cars so they use a different throwout bearing that slides over it.
Not specific to black or blue, the blue has some differences. The '94 blue tag uses a lift ring for reverse lockout, but the '95 & '96 use a "crash through" design that does not use a lock ring but uses more effort to push through to reverse. The black tag has some differences too such as a different speed sensor in the early years.
In practice there is very little difference. Both are very strong and even behind high horsepower motors they last well. I have both black and blue ZF's and I don't notice the difference in noise.
Although I like the thought of a stronger transmission, I like the '95-'96 shifter. So for me it makes almost no difference and currently have one black tag and one blue tag and like both.
Good luck.
Pro
Joined: Sep 2019
Posts: 716
Likes: 135
From: Buchanan, Michigan
best answer.. whichever one you can get with the lowest miles and decent price is the best option. you will be well over 500 horsepower before you start taxing either unit. so get whats available and affordable. make sure when you buy it the seller includes all of the bellhousing parts, shims, throwout arm, pivot bolt, hydraulic line. and all bolts. if someone took the time to completely remove it and properly gathered all the hardware you can be relatively sure it is in decent shape.
