jimman

I had an earlier post in regard to sticking in 4th gear with hurst shifter but got little to know response from the forum. I Will be posting photos on this link later tonight. The car has 40K with extended warranty. $2700 has caused them to come to inspect before repairs can be covered. The syncro gears slider tabs have failed do to improper stops with the short throw shifter. I was advised that the adjustable stops didn't have to be set do to the transmission has them already, well there might be a flaw in that thinking. The shifter has been in the car for nearly 35K and the wear pattern on the rods has raised some concern. Those can be seen on the photos. I'm hoping that this isnt so but will know for sure when it goes back together and they use the stock shifter and compare it to the Hurst but I was there and seen it and if doesn't look good. I am highly pissssed at myself for following the advise of some of our self procalmed experts on this fourm of which I've preached against but did it anyway.....my fault. Should have left well enough alone and as I've alway said GM isn't all that stupid and have the resources to check things out better than Clem Kadittlehopper in some speed shop.

Anouther concern is the color of the fluid, will have photos of that. Looks like it's lost its lube ability and caused the bearings to overheat as per bearing color. Didn't think 40K with not that much hard driving would have caused that. I have the original tires all the way around and the rears with 40K still have 30% tread left. I'm not looking for any more advise other than providing a warning to those with that shifter.

CAPN17

GM has had a problem with the 6 speeds overheating from extended driving as well as from compition driving. You might want to explore this, Corvette Fever did a lone, for them, article on it about 6 months ago. The article was combined with an install for a transmission cooler.

jimman

My question to the machanic as to the discoloration and he attributes to heat and it's a snow balling effect in that the reduction in lube vs temp of bearings and on and on it goes. Now I've made three cross country trips one of which was 8000 miles in less than two weeks got to believe that has something to do with it. Bottom line is need to change fluid more offten that I previously thought.

jimman

Obtain High resolution photos here: http://www.imira.com/Album/GuestView...%3FCPIndex%3D0

Y2Kvert4me

I'm certainly no "self-proclaimed expert" here...but it is very obvious right off the bat that it is in their best interest to get out of paying for this expensive warranty claim. Blaming the aftermarket shifter is their easy way out.

It is my understanding the stock shifter has no such travel-limiting stops. The adjustable stops on the Hurst will simply limit the travel, so I'm not sure how the Hurst can cause extended travel vs. the stock shifter which has no stops at all. This is just how I see it, but again, I'm not all that knowledgeable about it.

There seems to be a thread here nearly every other day about the M6 syncros going bad, so this certainly isn't too unusual of a problem for GM. If all these cases were caused by an aftermarket shifter, the correlation would be well-known by now I would think.

I think it's :bs and this is a perfect example of why to put the stock shifter back in before taking your car in for tranny problems.

:cheers:

VETTENV

:iagree: The Hurst shifter did not cause this.

0rodney@rpmtransmissions

This is the #1 failure in T56's. It is not caused by your shifter. My Stage IV units have the fix for this problem with aftermarket keys that I have manufactured. There are several things that contribute to damaged keys but I wouldn't blame it on your Hurst. The OEM keys are just hallow stampings that shear fairly easily and by reusing the factory keys they will break again. :banghead:

jimman

Will know more when it's reassembled will compare at that time the actual throw distance. Right now it looks like the stock shifter doesn't need stops because the leverage length isn't there as compared to the Hurst. Also, the tech is on my side and will change out the shifter before inspection. It is his experience that he's going on after 26 years of fixing these things and by the way he is a friend of mine and has no reason to falsely place blame. Again this is to try and fend off problems others might have if there is an adjustment problem. Since I drive over 50K per year as compared to 5 to 10K from most others on this forum it might save someone a problem down the road. For example, tires, the OEM has to meet over 40 design parameters that the aftermarket doesn’t have to concern themselves about. Knowing this one should be careful when making claims about relative performance and must point out the short falls along with the hype. I guess Murphy’s Law shows its ugly head, “one can’t get something for nothing and you can’t even break even”.

Also
"There seems to be a thread here nearly every other day about the M6 syncros going bad, so this certainly isn't too unusual of a problem for GM. If all these cases were caused by an aftermarket shifter, the correlation would be well-known by now I would think".

Been on this forum for over three years and can't remember all those threads on syncros, enlighten me. My 2000 had over 95k with stock setup and no problems at all.




[Modified by jimman, 5:19 AM 6/10/2003]

Jeff Jeff

I had to have my tranny rebuilt due to bad synchros. This was with 30k miles on it, stock shifter and NO mods, not even an airbox. I have seen quite a few posts on problems with the MN6.

I don't understand how the Hurst caused your problem. I would be looking at the burnt tranny fluid as the cause, not the hurst. If you road race (as your sig picture indicates) you need to change the fluid more often, and run a tranny cooler.

jimman

it puts the wrong position on the inside slider gear and exposes the guilds, dosen't look good. Also, the road race was my 15 minutes of fame. I think the fact I do a lot of long distance runs and I understand this trany dosen't like long runs.

Y2Kvert4me

Here's more than a few...besides the actual thread starters, you'll note how many people replied sharing the same problems and had syncros replaced. From reading them, it appears there may be a TSB out for it even.
http://forums.corvetteforum.com/zerothread?id=402172
http://forums.corvetteforum.com/zerothread?id=436799
http://forums.corvetteforum.com/zerothread?id=550056
http://forums.corvetteforum.com/zerothread?id=545434
http://forums.corvetteforum.com/zerothread?id=499515
http://forums.corvetteforum.com/zerothread?id=489833
http://forums.corvetteforum.com/zerothread?id=485352
http://forums.corvetteforum.com/zerothread?id=467478
http://forums.corvetteforum.com/zerothread?id=464913
http://forums.corvetteforum.com/zerothread?id=454086
http://forums.corvetteforum.com/zerothread?id=432548
http://forums.corvetteforum.com/zerothread?id=416471
http://forums.corvetteforum.com/zerothread?id=409520
http://forums.corvetteforum.com/zerothread?id=318142

Good luck with your repairs.
:cheers:


[Modified by Y2Kvert4me, 6:07 PM 6/10/2003]

jimman

Thanks for the info but the problem is not a bad sync gear it’s sheered guilds. The bulletin is on bent forks that have been a problem on earlier units since then they have changed that design. When you look at the throw it over extends the position of the inner gear exposing the guild and wa-la and iffy shift and you have your problem. Will find out if it’s the stops and what to do about it as soon as it starts to go back together. We are going to do a comparison with everything exposed to see what has to be done.

Y2Kvert4me

Ok, let me ask you this question.
Your original post stated you removed or did not set the stops on your Hurst, correct?
If this does prove to be the cause, shouldn't setting the stops as per the Hurst instructions take care of this problem?

I set mine up following the Hurst instructions...hold shifter in gear, adjust setscrew in until it begins to move the shifter, back it off slightly, tighten lockut. And yes, it is loctited too. I don't see what is to be gained by not setting them this way, it's very easy to do.


:cheers:

jimman

I agree but after looking at the wear pattern on the shift rods looks as thought the unit went to far. That's what we are going to determine after the unit is inpected by the extended warranty people and unit is being put back together. Want to see if the throw distance between the two are different. The tech showed how the position of the inner gear can cause the breakage now it's to see how it might have happened.

1LEThumper

"03.13.03
Tremec Transmissions
Service Bulletin 03.01
Subject:
Aftermarket Shifter Stops

Transmission Models Affected:
All

Severe damage may be caused by installing an aftermarket shifter with
"shift stops" on any TREMEC transmission. All TREMEC transmissions are
designed and manufactured with built-in shift stops to prevent over
shifting. Therefore; shift stops on aftermarket shifters are totally
unnecessary when used on a TREMEC transmission. TREMEC "TR series"
transmissions have multiple shift rails with shift stops on the gearing.
TREMEC "T series" transmissions have a single shift rail system with
stops built into the guide plate. When installing an aftermarket shifter
on a TREMEC transmission it is best to remove the shift stops to avoid
miss adjustment, and the potential of the screws vibrating lose. A
misadjusted shift stop can cause an under-shift, which may lead to a
gear jump-out situation. If the transmission jumps out of gear, the
shift fork can be bent causing permanent damage to the transmission.
Shift forks can also be damaged by "clash shifting". A clash is caused
by a missed shift. Neither an "under-shift", nor a "clash shift" can be
prevented by shift stops. TREMEC shift forks are designed to take loads
up to 1,000 lbs. However, a gear jump-out may well exceed 1,000 lbs. of
force, which may result in a permanently damaged
transmission."


Found this off a Mustang site. As to how the T56 is in a C5, I'm not certain but I do know that when Borg Warner was still making them it was impossible to overextend a shift unless you broke a main part of the housing or one of the forks some how was bent due to missing a shift or not using the clutch.

Those poor trannies never have been the same since Borg Warner sold everything to Tremec.....they really messed up a good tranny in my opinion

Highroller

When I installed my Hurst a couple of months ago I had a question ( wanted info on springs ) so i spoke with an engineer at Hurst and was told it was ok to go with no springs and he suggested either removing the stops or backing them off 2 or 3 turns, at that time he stated that the Vette tranny already had stops. I did this and have had zero problems so far, including no noise or rattles. After reading this I think I'll take the stops out completly.
:eek: :eek: :eek: :eek:

jimman

I read that artical also and I talked to Hurst people to. They recommended backing off the stops. The ware pattern on the rods has got some concern that is why when everything is exposed I want to see for myself what is going on. Don't want to go through this again. Like I said the sync gear itself is fine as you can see in the photos.

Highroller

If you have the opportunity please check on these purported stops. :leaving:

vettenuts

Once difference, and I don't say it is the problem here, is the much maligned rubber piece in the stock shifter. If you pull back into gear that rubber will tend to soften the input to the transmission when you hit the internal stop as when shifting hard the rubber will deflect. With an aftermarket shifter, without the rubber, you will instead pull hard on the internal stop (or likely harder then the stock shifter).

jimman

Vettenuts, that's a very good point and I never thought of it. Will try and observe that also. :iagree: