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Discussion Starter #1
hey guys in the c4 threads!
normally im over at the c3 threads lurking, but i have a few questions about the ZF s6-40's. First off let me tell you my intentions. I intend to install this trans in either the 77 vette, or a 70-73 camaro we are purchasing (gotta have a manual :devil: ). i would like this to be a cheaper alternative swap compared to the t56/t-5 swap kits, im roughly pricing out the swap right now and it seems to be. As i understand the bolt pattern on the bellhousing works for a first gen small block, making it an easy swap. ive been looking at a few websites including the forums on here, and couldnt find what im looking for, although http://www.zfdoc.com/ is a great help. Im not afraid of having to tear apart the trans tunnel or whatever to get it to fit, thats not my issue. I would like to get to know the trans a little better, seeing that you guys have it in your cars stock could you tell me a few things about it:
- is the clutch a hydrolic or mechanical?
-what are its weakensses?
-what (if anything) has broken?
-if broken, why, how many miles on it?
any background knowledge or other input/oppinions would be appriciated, thank you!
 

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In all the Corvette applications, the clutch was hydraulic.

There are two versions - an early one (identified as "Black Tag"), and a later one (ID'ed as "Blue Tag"). The color represents the background color on the label affixed to the transmission housing. The most substantial physical difference between the two are torque capacity, gear cut angle, and manufacturing location.

The Black tag units are rated for 450 ft-lbs of torque, while th Blue tags are rated for 400 ft-lbs. The Black tags have a smaller angle cut into the teeth compared to the Blue tag units - similar to the difference between the Muncie "Rock Crusher" transmissions and the standard Muncies of old. The Blue tags were manufactured in the USA, and the Black tags were manufactured in Germany.

The transition from Black to Blue occurred in 1993 sometime.

I don't know for a fact if the LT1 bellhousing bolt pattern is the same as the L98 or not, so you might need to make sure that you find a bellhousing from an '89 - '91 six speed.

I can't address any performance or reliability issues - mine is fine!

Steven
 

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I don't know for a fact if the LT1 bellhousing bolt pattern is the same as the L98 or not, so you might need to make sure that you find a bellhousing from an '89 - '91 six speed.

I can't address any performance or reliability issues - mine is fine!

Steven
89-90 Bellhousings were made of aluminum, the 91-96 are magnesium. Yes the 91-96 are the same, my Gm parts book shows 91-93 as the same PN (my parts book goes thru 93)

I have a 92 or 93 BH on my 89.
 

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Discussion Starter #5
Buy the t56 kit. Less work...
I looked into the t56 more now, and it appears pretty simple,i didnt realize that the adapter plate is readily available. i also didnt realize that t56's were put into mustangs, camaros, firebirds, vipers (and c5's but w/ longer input shaft?) so i guess that that might be the way to go, thanks everyone for the info, but if there are any horror stories for t56's/ZF's im all ears!
 

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My ZF6 with centerforce flywheel and clutch and Hurst short shifter shifts extremely fast between 1-2 and 3-4, but it sometimes misses third if I'm not careful. I replaced the clutch master cylinder at 80,000 miles. Other than that, I love it.
 

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I found a torque rating of 610 Nm which converts to about 450 ft lbs, but no horsepower rating. It didn't say anything for the T-56 either.
 
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