MontereyRedC6

Tom: As one of the best Corvette trouble shooters and problem solvers on CF, your opinion means a lot to me! Thank you!

oldmansan

I agree. When tjwong chimes in on a post/thread positively the worth of the post/thread is greatly enhanced.

San

carlrx7

i want the red ones

0tjw@wpe

Thanks for all the kind words guys! I became a supporting vendor here recently. But unfortunately I have been way too busy in my shop to do much. I was working past 8pm this evening finalizing a engine calibration on a LS7 that I installed into a 89 El Camino. The car is just a beast, breaking the tires loose on the dyno

Mez

So, what? Yes, I saw it listed in Wikipedia, too.

SBR is the most common synthetic rubber made with 76% of the world production of SBR used in car tires.

Using this logic, all of the rubber in every car made today "is not right" because one of the application of SBR also includes chewing gum. Every rubber hose, fan belt, shock bushing, weather stripping is made with SBR. So the fact it is used in chewing gum is irrelevant.

As you said earlier, we disagree on the solution an there is nothing wrong with that.

Now there are 3 options for people to pick from:

1. Rubber bushings - I am shipping now with shifter box mod instructions.
2. Solid bushings - Available with new shifters or eBay.
3. Urethane bushings - ?

Good luck.

Eric D

Yes, red would be much better damping than the stock black ones....unless they have them in blue. Everyone know that blue would be best......right?

AORoads

Why just red? j/k

I think this is very valuable information from 3 different people and quite a few more who've donated their time, effort and cars. I, for one, appreciate it. And I say that even if my MZ6 never needs a 'fix'.

But I don't doubt that if I keep the car long enough (or look hard enough), it will need it.

To all three, mitchy, mez and monterey/rfp, thank you. Every "marque" of cars has people like you. We just seem to be luckier than the others.

RFP

As the guy who started this thread, I thought it a good idea for me to jump back in and – in view of the nearly-conflicting “solutions” and frequently-conflicting “opinions” in this thread – try to refresh the thinking a little bit.

For starters, it seems clear to me that we need to define “solution.” In Post 45, MEZ reminds us



While I really do appreciate MEZ's "good luck" wish, I don't think luck has anything to do with it... one has to define the goals and do the work...

OK... I guess that I mostly agree with MEZ, but as a big believer that any project should have well-defined design goals (otherwise it is doomed from the outset!), I think that each of the "options" that MEZ outlines actually address different "design goals."

Here are some possibilities (your list may be wildly different!):

1. Design Goal #1 --- OEM rubber bushing are just shot, the shifter box flops around like a flounder, and you want to restore the "original factory feel." FIX IT! Good design goal, huh? Perfect for many, I'm sure. If this is your design goal, MEZ's rubber replacements should serve you quite well.

2. Design Goal #2 --- You are sick of "notchiness" of your MN6 and dog-tired of having to coax the thing into gear from time to time. Wanting to "fix" that seems a good design goal as well... although probably not for everybody (I am sure that some drivers have no problem accepting the "notchiness" and having to muscle the thing into gear sometimes). But if this is your design goal, Curt's urethane parts could be the answer.

Plesae notice that I said "could be the answer"... with the normal manufacturing variances from car to car, I can only speak for me, my "goal," and my results.

Before I go on, I have to say that I think MEZ's "option 2" is a non-starter. I strongly believe that the B&M bushings (OK, they are really only "spacers") are a fundamentally flawed design. They raise the mounting height of the shifter box so that it is no longer supported from below. I am convinced that this three-point support is important. I would not use the B&M parts on my car. The B&M parts reduce the number of mounting/support points from three down to two. Ungood! .

“Solution” for me meant that my 6-speed would actually snap into the chosen gear without a lot of coaxing and that the entire shifter would have a certain precise “feel” consistent with my own image of “Corvette.” Reading below, you see that I was at least somewhat serious over the last year or so in chasing this elusive “solution,” spending the bucks for a MGW shifter and for Red Line Synthetic lube.

In those prior months, I had sought a cure for the irritating way my MN6 was frequently reluctant to go into gear (with the worst offenders being first and second gears). Further, it just had an over imprecise feel and - although I could live with the irritation - I wasn't happy with it. That was why I bought and installed the superb MGW shifter (which helped), and had the transmission and diff fluids changed to Red Line synthetic (which also helped).

The operative word here is that these two upgrades to my car "helped"... but vestiges of the old irritations remained.

Then, last Thursday, the urethane parts were installed.

Even the short drive that I was able to squeeze in last Thursday afternoon clearly revealed a huge improvement. Now, having driven the car many miles over the weekend and into the early part of this week, I can say that I am through, done chasing a cure for my former gearbox woes! This thing is as bolt-action precise as the Chevrolet designers probably wished that their original design had proven to be.

I am delighted… I have found “my” solution… as I said earlier, the “solution” for you will depend on what you are trying to solve!

Like the old saying, "you pays your money, you takes your choice!"

Rb

mitchydkid

Guys, I have not enjoyed a thread this much in quite some time.

I think I will stir the "thought pot" a little more. Here are some more thoughts about shift feel and finding your gears. Rob, your last post triggered this. It will sound like I am challenging your solution to transmission feel...because I am. But I am not challenging because I flat out disagree, rather because I have some observations and different opinions on where the feel of the transmission shifting comes from. This does all partially relate back to the original topic of shifter box bushings and the MGW shifter.

First, lets talk about how difficult some of the gears can be to shift into. Now I don't know all there is to know about the transmission, but I DO know that there are absolutely no "gates" or "notches" in the MGW, Stock, Hurst, or any other Corvette shifter. If you hold the base of the shifter when not installed you can move the stick anywhere with no gates, notches, or whatever. The gates and notches come from the transmission itself. There are two sources of shift delay that I know of. First source is the detent (sp) plate. This plate has detents in it that catch on a spring loaded ball when you are in gear to help you stay in gear. Want to know more about this? Do a search on "Anti-Venom Mod." This mod eliminates the effect of the detent ball/plate and allows you to shift into gear with no resistance from the ball/plate. It also allows you to knock the car out of gear if there is little tension on the gears in the tranny. The other source of pause or delay in shifting is in the synchros. If you shift at the perfect time you will allow the synchros to not have to work hardly at all and the shift will happen faster. Shift at sub optimal RPMs or skip from 2nd to 4th and you will have to wait longer for the synchros to do their job. Holy smokes Dale, what are you babbling about! Simply said, I am saying that I think there is little a shifter or its mounting can do to fix some of the feel problems the Corvette has because i believe those problems are in the transmission design.

That being said, I do think that "some" of the feel comes from the shifter mount box. I add this experience to the knowledge pool. I've had my clutch replaced 3 times because I am picky about my shifting experience and the stock clutch is a piece of garbage (the pressure plate to be more exact.) I've noticed that the difficulty many face when finding 1st gear changes every time the darn shift box is removed and replaced. When the car was new, finding 1st was always darn easy. Dealer reluctantly replaces crappy clutch and finding 1st issue is GONE! Crappy replacement clutch does not fix problem so I go with after market clutch. Now its VERY hard to find 1st gear. I did not like the after market clutch and had it replaced with different after market clutch and now my finding 1st problems are diminished but slightly still present. My point? Small variables in the mounting of the shifter box CAN affect the way your car shifts. For this reason I am looking forward to an opportunity to test out Curt's bushings. Curt has put mucho effort into this thing and if it does what Rob says it does it could make the Corvette a more refined driving experience (thats good.)

Final thoughts on tranny feel. I wish someone would do an in depth study on tranny fluids. <----------Please, no inappropriate jokes. I have read so much about these fluids. Some say AMSOIL will fix all problems. Others swear by Royal Purple, Redline, or another brand. Still I have read that these are all snake oil and they have no effect what so ever. I guess if you lay down serious coin on fluid you are very likely to feel a difference whether it is there or not. Kind of like drinking bottled water instead of tap water. Curt, could this be your next project after your shifter fix is final?

Ok, I better get back to work.

-Dale

PS. Does anyone know if the Anti-Venom Mod can be done on TR6060 transmissions? I've only read about it being done on the T56.

RFP

Good post, Dale... thought provoking as usual!

I am quite familiar with of all those transmission-esque things you mention... indeed, there are no "gates" or "notches" in the shifter (a'la mid-50s Ferrari). "Notchiness" is a word that somebody coined long ago to describe the frequent goofiness of the MN6 Corvette transmission. When the word is used, probably most 6-speed drivers know what's being talked about.

As to the synthetic lube (I happen to have used Red Line... it is what LG Motorsports uses and they did the "fill" for me): The Red Line simply made my transmission behave pretty much the exact same way dead-cold or all-warmed-up... makes no difference. Before, my transmission was way "notchy" (dontcha just love it!) when the car was "cold."

If you want to loose sleep about transmissions and shifting, here's a little known fact that would make Cliff Claven proud: When moving the shift lever from side to side (through the "netural gate" heading toward 1st/2nd or 4th/5th/R), there is a bit of lateral movement of the shifter box output shaft... it's moving sideways when it should be rotating. The bushings or bearings or Silly Putty that the output shaft rides in allows what seems to me to be more lateral "play" than would be optimum. "Preciseness" of the shifter should be better if there were only rotation of the shaft when the lever is moved from side to side. I guess we will investigate this next... Hey, Curt!

As for Curt's magical urethane parts, they did, indeed, work magic on the shifting "feel" in my car... drive on up to Hurst and I'll gladly demonstrate!!

Of course, YMMV

Rb

RFP

Hallelujah !

Another convert to the group of believers that the "V" (and Blade, as Zoxxo points out) is important!

The pointey-thing that Zoxxo calls the "blade" (good term, by the way!), is actually covered (or "coated") in rubbery stuff from the factory. With the shifter out of the car and in your hands, it's pretty easy to see just how much force the blade was bearing into the "V" (you can tell by looking at the burnishing of the rubber blade covering)... on my car, there was good evidence that the blade was "bearing down" into the "V" with very little force. Curt designed and casts his urethane "V" bushings with a bit of extra height to cause earlier engagement of the blade. After the installation of the urethane stuff in my car, it's clear that the blade is really forced down into the "V," giving excellent support and rigidity ... but with NO rattle.

Rb

MontereyRedC6

Hey Brian /Zoxxo:
I don't consider your comments branching off at all. The insert on the bottom of the stock shift box is actually a hard plastic. When the top bushings flex or actually give way the next thing to stop lateral movement (which is actually rotation of the shift assembly) is your "blade". But, because most of the ones that I have seen barely touch the effort to stop the rotation is only at the end of the arc. This results in a random feeling of position of what people imagine is the shift gate back in the transmission. This happens going up or down in the gears.

Then, a different problem appears for most users that stop all movement with what I'll call the old Z06 shift box (since it's now discontinued) or the B&M solid bushing is that all vibration is driven up the torque tube and shift rod. Notchy, you bet.

My design builds up the support at the base with a urethane that is not as hard as the hard plastic the factory uses. Combined with my firm top bushings you now have a three point firm positioning of the shift assembly which defines the range of motion and effort and makes finding the chosen gear very predictable. And, this support is continuous and consistent. This can benefit stock as well as aftermarket shifters. It may even eliminate as much need for damping in the shifter assembly or the shift ball. It's a noticeable change. More on that last statement later.....

I'll tackle the old Z06 shift box when I catch up from working on the stock C5 /C6 boxes. Yes this applies to the C5 as well!

Brian: Hijacking? Not at all! What shift box do you have currently and what shifter? I need additional data points as I have product available. Post here if possible or me if you prefer and I'll respond by PM.

Thanks very much for your input! Curt

MontereyRedC6

You can likely count on some changes in the rubber bushings over time. Without knowing your car and your objectives only you can answer if you want to take a look now or plan on a change and remove your console one time when you have the parts ready.

You already have the MGW. Which one? The three generations are distinctly different, at least to me.

Your satisfaction or lack of it will guide to toward an answer. How do you like where you are now?

Curt

MontereyRedC6

Dale: Glad to have you around. I'll work on this question for the moment. There are a number of discussions about Amsoil ATD (used in commercial Allison automatics) in particular on the CF C5 areas. I did not make my decision based on anything here on CF. I gave ATD a try after my second MGW shifter while still looking for more answers. I chose ATD based more on discussions at bobistheoilguy.com than anything else. I consider the discussion on lubrication there to be above average. More emphasis is placed on used oil analysis there than seat of the pants. More realistic answers and less mine is better than yours discussion. Do I like it? Is exotic ATF a cure all? Did it make a noteable difference?

Well, I have kept it in and would likely use it next time. I have three gallons of it around but that's not the only reason. It seems more consistent. If I had the change I have now with bushing mods, maybe just maybe, I would still be using Dex3 successors but not likely. Good reading over at BITOG. Check it out! \

Curt

AORoads

"...swapped out for the Katech flywheel and the ZR1 dual disk clutch. The only noticeable difference (besides the nice bite in the clutch pedal) was a small increase in vibration through the shifter! I tend to rest my hand on the shifter so I was used to the old feel..."

Not to take the thread in a different direction (aka high jacking thread), but what would you assess to be the reason for more vibration due to a clutch change?

RFP

I suggest that an even better 'experiment' would be to peel the thin rubber factory 'coating' from the "blade" and install Curt's urethane part. This would ensure that the "blade" was always solidly against the 'V' no matter what, ruling that out as a source of dumpster pounding noises.

RFP

The [potential for] "front to back" movement that is designed into the shifter box mounting is to allow for correct alignment with the transmission linkage. When reassembling the shifter to the transmission linkage, a small metal part (pin, dowel, factory-supplied "L-shaped doo-dad, whatever) is inserted through a hole at the front of the shifter box (through the box bearing and the output shart) thereby setting the correct position for the box/linkage in the "neutral" position. Once the pin is correctly inserted, the shifter box is bolted down. Again, the "fore and aft" is simply to allow for the correct alignment of the moving parts.

Katech_Zach

Vibration through the shifter is usually an installation issue and can be corrected by adjusting the shifter.

RFP

I'm afraid that we are just going to have to disagree on this.

Manufacturing tolerances (and the significant tolerance stack-up that comes from such a complex bunch of bits) dicates that the shifter linkage (the part to which the shifter box output shaft connects) will vary considerably in its as-assembled location in the car. The amount of variation is predictable. When the transmission is in neutral the linkage will lie somewhere between "x" and "X' ". To install the shifter box to the linkage in it's defined "neutral" position the shifter box must be movable within the [predictable] range expected from the transmission linkage as-assembled. Thus the slotted bushings and the "V" with some wiggle-room fore and aft.

The "blade and "V" is an elegant - and dirt cheap - way to provide this needed wiggle room.

That's the way it is in the wonderful world of engineering... parts - and assemblies - have to be designed to go together on the assembly floor with built-in allowances for norman tolerance stack-up. And, "yes," I've done this before, too... but having done it before is not required to understands the design and manufacturing engineering involved.

You wrote: "Again, if the shifter box wasn't meant to move (a little)." Think about that again. How much is "a little?" How much is "too much?" What is the purpose of this little-bit-of-undefined-and-uncontrolled movement?

Front to back movement is not designed into the shifter box.

Back 2 u!

MontereyRedC6

errr....The old Z06 shift box when torqued to specs is not going anywhere. Not fore not aft and is, once adjusted fore and aft, a solid part of the torque tube.