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That is a fantastic video....but in spite of the quality and quantity of the vid, I'm somewhat on the fence. It really doesn't seem much louder than mine...maybe a little.
The more concerning issue is that you feel there was a sudden change in noise.
There are a few options;
*Change to a different kind of oil
*look in your old oil for metal/bearing material. When I've dropped oil in failing trans' in the past, there was no doubt that something was going wrong. There was metal everywhere in the oil.
*send some oil for a sample.
*Drop the trans and inspect.
IIWM, I'd start by changing the oil, and inspecting the Amsoil 5w30 that came out.
And no, I definitely do not think "frequent Trans oil changes flushed all the synchro wear particles out and is no longer providing a cushion for the gears and bearings?"
Wear particles are in no way, "good" or "cushion" for bearings and gears. What you want is good, clean, contamination free oil in there.
Did you check the bellhousing alignment during the swap? That LS motor doesn't have the power to bust a properly set up ZF drivetrain. I know you ended up using a quick time bellhousing with some modifications. Gearboxes can whine if not perfectly spot on lined up after the bellhousing is fastened to the block, and possibly a host of other issues. I sent a paypal to ZF Doc recently for some quick parts after he sent me an invoice, so he is still doing business.
Yes, I bought Lakewood adjustable dowel pins. If I remember correctly it was dialed in to within .005" but i never checked for parallelism between the engine side and trans side after welding. Even still the whining noise was a sudden change from "normal" 30mi ago after an Trans oil change (Amsoil manual trans fluid 5-30). Engine and trans bolts are tight and doesn't appear to have shifted in any way.
It's good to hear ZFDoc is still in business, Does he have a forum profile I can P.M? Whats the best way to contact him? I was talking to a local transmission gear shop and he stated it was going to be extremely hard to find parts for a ZF6. He was shock that parts would cost $2K his cost!
It's good to hear the ZF6 is strong. It really sounds like a rebuild is the better, slightly cheaper route to go. I priced out a T56 Magnum and its supporting parts and fab time to be higher than the cost of a ZF rebuild all things considered.
I wonder if there is any trans oil additives to help quiet down gear noise?
That is a fantastic video....but in spite of the quality and quantity of the vid, I'm somewhat on the fence. It really doesn't seem much louder than mine...maybe a little.
The more concerning issue is that you feel there was a sudden change in noise.
There are a few options;
*Change to a different kind of oil
*look in your old oil for metal/bearing material. When I've dropped oil in failing trans' in the past, there was no doubt that something was going wrong. There was metal everywhere in the oil.
*send some oil for a sample.
*Drop the trans and inspect.
IIWM, I'd start by changing the oil, and inspecting the Amsoil 5w30 that came out.
And no, I definitely do not think "frequent Trans oil changes flushed all the synchro wear particles out and is no longer providing a cushion for the gears and bearings?"
Wear particles are in no way, "good" or "cushion" for bearings and gears. What you want is good, clean, contamination free oil in there.
The last oil I drained only had ~500mi on it and I could see right through it as it was draining, like it was brand new. Even looking into the oil pan it drained into was like brand new oil. At this point I will drain and check the oil and inspect if there is a failing bearing / steel flakes.
About the flushed particles, I was thinking to something similar to how ZDDP works in engine oil for flat tappet lifters. The worn in synchros being a softer material might act like ZDDP, maybe?
Yes, I bought Lakewood adjustable dowel pins. If I remember correctly it was dialed in to within .005" but i never checked for parallelism between the engine side and trans side after welding. Even still the whining noise was a sudden change from "normal" 30mi ago after an Trans oil change (Amsoil manual trans fluid 5-30). Engine and trans bolts are tight and doesn't appear to have shifted in any way.
It's good to hear ZFDoc is still in business, Does he have a forum profile I can P.M? Whats the best way to contact him? I was talking to a local transmission gear shop and he stated it was going to be extremely hard to find parts for a ZF6. He was shock that parts would cost $2K his cost!
It's good to hear the ZF6 is strong. It really sounds like a rebuild is the better, slightly cheaper route to go. I priced out a T56 Magnum and its supporting parts and fab time to be higher than the cost of a ZF rebuild all things considered.
I wonder if there is any trans oil additives to help quiet down gear noise?
He's got an email: billb@zfdoc.com If you google ZF Doc, his website should come up and his contact number is on there. Nice guy to talk to, you can't go wrong with at least taking some time to explain your issue to him. I ended up purchasing a heavy duty tailshaft bushing, a few seals, and a gear shim kit from him while I've got my ZF sitting on the garage floor. I know the black tags can be a little noisier. There have been all out wars on this forum on what oil to run but I run Pennzoil Synchromesh in mine. You put in the time fore sure on making that quicktime mate up the ZF, I'd be proud of that and stick it out.
I have window shopped the Tremec T56 Magnum too....it is absolutely a great piece. The trans alone is $3000 not counting the clutch, hydraulics, driveshaft, and nickle dime fab pieces.
I have been abusing my ZF blacktag for 20 years. My 91 has a 464 Dart tall deck with a 300 shot of nitrous, and runs 9.70's@145 with the DA at 6400ft. It should run 9.60s@7000ft DA. It probably has over 1000hp and over 1000 ft/lbs tq on the spray. I dump the clutch at 5000rpm on the nitrous with Hoosier 29X13.5 slicks, and it's run 1.3 60ft times, and I have never hurt the trans. I have hurt everything behind the trans but never hurt it. I have deadhooked this on nitrous several times and still never hurt it. One thing the ZF blacktag has near straight cut gears and a 32 spline mainshaft. There are several different variations of the T56. The F body T56 is the weakest. It has a 27 spline mainshaft and helicut gears. I have seen several and rebuilt several F body T56's that either snap the mainshaft in two or twist the mainshaft. I have seen 12 second F bodies break mainshafts. The Viper T56 is a totally different animal. It still has helicut gears, but it does have a 30 spline mainshaft. So even the strongest T56 isn't as strong as the ZF with it's 32 spline mainshaft. Every spline count matters as far as strength goes. And a near straight cut gear is going to be stronger than the helicut gears. The helicut gears have less surface area for gear contact. If you physically break a trans, it's usually a gear/countergear problem, or you break or twist the mainshaft. The ZF black tag problems I have seen are synchro problems from drivers who don't know how to drive, and could ruin the synchros in any trans. But for a factory trans, a ZF has to be one of the strongest transmissions ever put in a car.
Back to the original topic. I don't know if I missed it, but a single mass flywheel with a unsprung solid clutch disc will make all sorts of noise in 1st, 2nd. and 3rd. If you have a single mass flywheel, you need a sprung hub disc. A aluminum flywheel and solid disc will make all sorts of noise. But every with everything correct, the blacktag will still make some noise. That's from the near straight cut gears. I'm sure that's why they went to the blue tag trans with helicut gears, to quiet down the gear noise. But that gear noise is what really adds to the strength of the trans.
And for what it's worth talking about the LS7 and the TR6060 trans, those are a transaxle. So it's really apples and oranges comparison. So you aren't just going to bolt one of those in a C4.
Last edited by tpi 421 vette; 04-23-2017 at 10:43 PM.
Can you prove that with actual data to back you up?
So I did a little investigating today and found out some interesting data about these (and other) transmissions. PART of what made me curious was this thread...the other part was learning more about the NV3500 -a trans that I'm in the middle of rebuilding. Anyway I got curious and started looking around. I found this quote from a HOT ROD MAG ARTICLE:
"The strength of a manual transmission is related to four main design functions consisting of cluster-to-mainshaft center-to-center distance, First-gear ratio, gear-tooth pitch, and the alloy of the steel used to make the gears. "
None of that is new to me... but this data from the same article was of interest to me:
Center to center;
T5 - 77mm
T56-85mm
I knew that the T56 had a substantially larger center-center distance than the T5 had....I couldn't remember the actual numbers. Anyway, 8mm. The T56 shafts are spread 8mm further than the T5 and that is where the at least a portion of it's increased tq rating came from, over the T5. However, the ZF6 goes another 10mm further than the T56! Here is what else I found:
NV3500-85mm (same as the T56) ZF6 - 95mm
Wow. Of the 4 main design features that HRM feels govern trans stregnth, we can now confirm that the ZF6 holds a substantial advantage in 2.5 out of those 4:
*Center to center with a 10mm larger spacing
*The cut of the gears
*FIRST GEAR RATIO (about 1/2 of T56's have a numerically higher first gear ratio than the 2.68 found in the ZF6. The remainder have a similar 2.66)
The final design feature listed in HRM; the make up of the metal -we don't know. I don't anyway. There are many other criteria that influence trans strength too, to be honest; bearing size and design, shaft sizes, gear widths, spline lengths, case strength...probably a lot more. The ZF6 weighs ~25 lbs more than the T56 -evidence of "more beef". Hopefully, this actual data (plus the output shaft spline count provided by Jim) helps back up my original option; I would never replace a ZF6 with a T56, and that comparing the two...there is no comparison other than that they're both 6 speeds.
QUICK!!! I need to know what are all the all the differences between Black and Blue tag ZF6. I know the splines and TB are different, I don't care I will replace the clutch due to extreme chatter. Are there any other issues or deficiencies that make this trans not as good other than strength?
Absolute torque limit?
NVH (better right?)
reliability / wear resistance?
Interchangeability between Blue / Black tag?
Last edited by MrVette90l98mt; 04-25-2017 at 05:31 PM.
Torque on blue tag is 400, down from 450 on black tags but will still be up to the task of being behind your motor. Depending on the year of blue tag (94-96 I believe) will have a crash through style reverse gear. Doesn't have a plunger to pull up to access reverse, pressure applied lets you grab reverse instead. Only differences I know. ZF Doc's website may have a comparison list contrasting the two tags.
Last edited by 1985 Corvette; 04-25-2017 at 05:37 PM.
Torque on blue tag is 400, down from 450 on black tags but will still be up to the task of being behind your motor.
Know that the tq rating isn't an "absolute" rating; it won't break over 400 lbs. That is the rating given to that trans, after passing x number of hours, operating at y torque input. ZFdoc's website has a paragraph explaining validation of the trans, which I'd guess was done/ w/the LT5...not likely the L98....
"The ZF S6-40 test program for design acceptance for release into production was defined by General Motors Uniform Test Standard (GMUTS) R15-6. This involved 15,000 miles of full-throttle up-shifts at engine redline and downshifts to redline. This was done mostly up and down a 7.2 percent grade on the GM Proving Ground In Milford, Mich., and included wide-open-throttle runs uphill in reverse!
Another test involved 200,000 highway and proving ground test miles, while still another test involved about 80 hours of high-speed testing on various racetracks and at the GM Desert Proving Ground in Mesa, Ariz. This was followed up by a thousand miles of testing on the high banks at Talladega Super Speedway in Alabama."
Note that if I google "General Motors Uniform Test Standard (GMUTS) R15-6", I can't find anything but the same quote from the same source, but there that is. Anyway, the tq "rating" of a trans isn't the tq above which the trans will break; above that tq, trans life won't likely meet the original criteria (100k miles, 200k...whatever it was).
QUICK!!! I need to know what are all the all the differences between Black and Blue tag ZF6. I know the splines and TB are different, I don't care I will replace the clutch due to extreme chatter. Are there any other issues or deficiencies that make this trans not as good other than strength?
Absolute torque limit?
NVH (better right?)
reliability / wear resistance?
Interchangeability between Blue / Black tag?
There are some differences between ZF's.
The splines are the same.
'89 to '93 used a different front input shaft guide tube (I'm not sure of the part name) than the '94 to '96's used. They are a different diameter so require a matching throw out bearing.
There are two types of ZF's. The Black tag is the earlier version from '89-'93 and have straighter cut gears. The later Blue tag from '94-'96 has more helical cut gears. The early ZF's are slightly stronger torque rating (450 vs 400 ft lbs), but can make a little more noise.
The shifters are different too. The early '89-'94 have a reverse lift ring to engage reverse gear. The '95-'96 have a "crash through" design that does not require a lift ring, but just takes a little more effort to push it into reverse.
Either an early or late one can be used, just make sure you get the right parts to make everything match.
I have swapped between the early and late and they both will work fine.
There is actually another type of ZF also. The ZR1 ZF 6 speeds have a longer input shaft and will not work in an L98/LT1/LT4. I am not sure, but I believe the early/late differences apply to the ZR1 transmissions also.
Awesome! I found a whole Blue tag for sale. I messaged them for more info, still waiting, don't want to miss out. I don't plan on big power anytime soon so a blue tag will do. Do we know for sure if the TB changed along with the blue Tag or was it with a model year change? (2 TB sizes for a blue tag)
Edit: Never mind, got a little excited, too many things to track at once. The tube diameter follows the tag type.
found this from a post on this forum about input shaft length:
WVZR-1 wrote "159.5mm for the L98/LT1 & 4 (6.27953 in)
190.5mm for the LT5 (7.5 in)
That's case to the tip of the input-shaft"
I think I will try and make a deal for this Blue tag ZF. I will keep my Black tag...who knows it might be worth a million bucks in a few years, lol!
Last edited by MrVette90l98mt; 04-26-2017 at 01:23 AM.
Reason: adding info
I have no idea how this all worked out but I just scored a New Original Stock virgin Blue tag ZF6 from a guy in S.F. for $2,200!!!
Gonna save up a few bucks and probably have the shop I use to work at swap the trans...I really don't feel like having to R&R a ZF6 on jack stands or pull the engine and trans out together.
Yeah if you can have the shop install it, that'll save you some cussing/cursing under the car on your side while trying to get the trans to mate up to the motor. I have to do it again in a few weeks as my ZF sits on the floor. It's sat there for two weeks because I do not look forward to wrestling it in place.
Pretty confident my Black Tag's condition is terminal. I inspected the oil after 130 miles and found a bunch of steel flakes in the oil...way more than what should be there after 130 miles! So if your ZF6 whines as bad as mine does in my previous video, who knows how long you have.
Pretty confident my Black Tag's condition is terminal. I inspected the oil after 130 miles and found a bunch of steel flakes in the oil...way more than what should be there after 130 miles! So if your ZF6 whines as bad as mine does in my previous video, who knows how long you have.
I just has a similar problem w/an NV3500 in my truck. Whining noise, metal in the oil, just like your vid...all that combined with 296,000 miles, I was sure it was a bearing going out.
I took it apart and the 5th gear on the counter shaft had slid rearward (5th was an interference press fit on the counter shaft) and was trying to saw through the trans case. Turned out to be an interesting find, and easy fix.
04-22-2017, 10:33 PM
Know that the tq rating isn't an "absolute" rating; it won't break over 400 lbs. That is the rating given to that trans, after passing x number of hours, operating at y torque input. ZFdoc's website has a paragraph explaining validation of the trans, which I'd guess was done/ w/the LT5...not likely the L98....
