Club Cobra - New Tremec transmission

Club Cobra (http://www.clubcobra.com/forums/)

- ALL COBRA TALK (http://www.clubcobra.com/forums/all-cobra-talk/)

- - New Tremec transmission (http://www.clubcobra.com/forums/all-cobra-talk/144218-new-tremec-transmission.html)

Quote:

Originally Posted by eschaider (Post 1486079)

The simple answer to your question is in bold about midway down this post. The why and wherefore stuff is what is in front of and behind the answer.

For transmissions, strength is not a horsepower metric it is a torque metric. Most enthusiasts loose site fo this and fall back onto the romantic notion of who has more horsepower going through their transmission as an indicator of strength. Transmissions are torque multipliers and as such their measure of strength is their capacity to transmit torque.

There are three metrics that in large part determine a transmission's torque capacity (strength);

The first is the center to center distance between the mainshaft and the countershaft. The greater the distance the greater the torque capacity — all other considerations being equal. Larger center to center distances provide larger levers if you will.

Think of the distance from the gear tooth's optimum tooth contact point to the center of the gear as a lever. Just like when you use a pry bar to open a box, the longer the pry lever the greater your leverage. In the transmission it is similar but we rely on the gear ratio for the leverage. The center distance is a measure of how much gear mass that leverage (torque multiplication) is spread across. Not surprisingly more is stronger less is weaker.

Now expand the single gear image in your mind to two meshing large diameter / large center to center spaced gears vs two smaller diameter, smaller center to center gears. You don't need the math to get the right answer. The bid stuff wins every time!

The second metric is gear face width. This one is comparably straight forward. Wider faced gears are stronger than narrower faced gears. It's not rocket science. Once again in this situation more is better.

The challenge the design engineer has with large diameter, wide tooth faced gears is inertia. When you change gears, it is the synchronizer's job to match gear speeds on the gear change so you have a smooth (hopefully fast) gear change possible. The large diameter wide tooth faced gears have huge inertia.

That is one of the reasons the TKO shifts so poorly. It literally uses 1960's Top Loader synchronizers to attempt to synchronize much larger heavier gears than they were ever designed to handle. When Trmec did the T-56 they initially used double cone synchronizers because the gears were so huge. Later for selected OEM customers they began to supply (without a lot of fan fare) triple cone synchronization which later found its way into the T-56 Magnum.

The third and final (for this discussion) metric is the steel and it corresponding heat treat that the gears are made out of. We all have heard the common 4000 series molybdenum steel designations like, 4130, 4140, 4340 etc. There ar other steels up in the 8000 series that are used is some ring an pinions and a few specialty steels like the high nickel 9310 steel that is useed by Rockland Gear in their T-56 Tranzilla six speeds.

The overall strength of a given sized gear can be enhanced through the selection and use of specialty steels heatreated to a particular strength and hardness. Generally harder, tougher (hard to get both together) and higher tensile produce more desirable gears but each comes with it own set of idiosyncrasies the need to be catered to for a successful implementation.

Tremec uses a proprietary steel that has served them well (for the most part) in daily driver type applications. Rockland uses a particular 9310 alloy and heat treatment for the strongest T-56 six speed derivative available any where today. The Rockland T-56 style Tranzilla has a torque rating in excess of 1000 ft/lbs of flywheel torque. Liberty uses yet a different alloy for their Prostock clutches transmissions. Each alloy / transmission design is optimized for the target market the manufacturer was aiming at.

Now to your original question about the 1⅜ inch Top Loader input shaft.

By increasing the diameter of the input shaft you increase its strength only. It will have no impact on the strength of the gears internal to the transmission only the input shaft.

This becomes apparent with the original Tremec T-56 offerings for the Mustangs. Originally, they used a standard Ford input spline configuration. In service behind the supercharged 03/04 Cobra's these shafts began to shear off. The Tremec fix was to offer a larger diameter 26 spline input shaft based off a GM spline spec. It wasn't the spline count that saved the day (although it didn't hurt) it was the larger diameter input shaft. The input shaft change in diameter had no effect on the torque capacity of the transmission's internals, they remained the same.

You will see transmission manufacturers from time to time rate a transmission they offer at a particular torque spec. If you ask them how the transmission's torque capacity was determined (and you are persistent enough to pursue the answer) you will find that they have no real torque rating capacity available to them or that they want to use. Tremec does and for the most part their recommendations are pretty much the way it really is.

The aftermarket manufacturer that is blowing smoke up your behind will couch his torque rating representation with words like, "but not in a heavy vehicle" or in cars below XXXX lbs. This is someone who is trying to sell you a transmission and doesn't want the diminished torque capacity of the design to kill his sale. you should put as much distance as you can between those businesses, their transmission and your car as you can.

If a transmission is capable of XXX ft/lbs of torque transmission then it can do that in a light car or a heavier car. XXX ft/lbs is the same in either situation. What is not the same is the impact the gear teeth see at the time the clutch is released.

The shock loading on the gear tooth face from an aggressive clutch goes up considerably as vehicle weight increases. FWIW aggressive clutches that shock the drive train do nt perform as well in a race environment as a smooth engaging clutch that does not shock the driveline.

Ed

Install "X" transmission in your car and get "Y" results.
Oh Jesus effing Christ man... blow it out your ass! Seriously, ban me from this site but dude you can't please everyone, especially your sorry ass. Do you work for Tremec??? No seriously, you must work for Tremec with as much horse**** as you spew here! I'm tired of this ****, another prima donna spewing hore**** here. Tremec is the ONLY transmission??? Give me an effing break!!! Obviously you have never raced ANYTHING. Please, enlighten us with your racing experience!!! Oh, I'd love to hear that!!! Go karts, slot cars... what else??? Oh, hold on...let me pull that up from XYZ's website and give you a bull**** answer!!! Again, these internet commandos have ALL the answers!!!! Please, adhere to all their recommendations and ask what NHRA team they work for...

Quote:

Originally Posted by jetblue69 (Post 1486171)

Wow! Bad day...?

Surprised me too, Glen. He seems to initially think I am attacking Tremec and then he suggests that I work for Tremec!?!? Without skipping a beat he steps up his game with some personal attacks and then spirals down into an unrecognizable sort of banter that feels like another personal attack but is far too convoluted to comprehend.

His follow up commentary about keyboard commandos is also curious. It would appear that he is attempting to project certain personality traits, of his own, onto others he has chosen to dislike — for whatever reason.

I think you were right in your observation about a bad day or perhaps night?. It really is difficult to understand otherwise ...

Ed

Yes, surprised me also.
One minute asking about alternators; and then not long after, aggressive behaviour towards a longtime well educated member.

Some people just don’t have the temperament for forums and the back and forth and should probably just stay away.

A member for 8 years and only 74 posts suggests a quiet fellow.

With the plague, people dying, and political crap happening, and not knowing any personal circumstances, I vote to drop it and let it pass.

No point in piling on when someone has already blown a gasket. Just let them know they are still loved.

Quote:

Originally Posted by olddog (Post 1486235)

Just let them know they are still loved.

Uhhhh, what if they're not?:confused:

Quote:

Originally Posted by DanEC (Post 1486220)

Some people just don’t have the temperament for forums and the back and forth and should probably just stay away.

Patrick should heed this advice. :p

Great all you guys can talk about is banning people instead of machining a new rail for the5th gear reverse.

Quote:

Originally Posted by hauss (Post 1486240)

Great all you guys can talk about is banning people instead of machining a new rail for the5th gear reverse.

Naaah, you've got to work really, really, really hard to get banned from here. Otherwise, Jamo would have banned me years ago.:cool:

Quote:

Originally Posted by patrickt (Post 1486241)

Naaah, you've got to work really, really, really hard to get banned from here. Otherwise, Jamo would have banned me years ago.:cool:

Patrick, God knows your factual, literal responses to various posts and posters have provided me (many of us?) with good information and ideas along with an unbridled and entertaining relief over the years, but this one, I think, needs some healing time, as Rick suggested. I took the cheap shot out of the end of my previous post because it added nothing positive and only served to stir the pot (I know, I know).

BTW I believe you are right about Jamo and what it takes to get banned. That is an achievement few are capable of. Look how long it took Evan. :)

Ed

So as I was saying I am about to talk to a machinist friend of mine but before I do anyone interested in a 5th gear reverse rail for a tko 600 ? It is new and improved no more roll pin removing to much material from the rail making it weak.

Quote:

Originally Posted by hauss (Post 1486244)

Do you have a design drawing and price?

Ed

Interesting thread on TKO problems

https://www.corral.net/threads/probl...tranny.678765/

Quote:

Originally Posted by Anthony (Post 1486278)

Interesting thread on TKO problems

https://www.corral.net/threads/probl...tranny.678765/

The sad story that Tallimeca (and 11 pages of other owners) tells is just one of many similar types of encounters TKO owners have had with Tremec Customer Service over the years. In the FWIW bucket his story was near the beginning of the TKO era almost 20 years ago now. Time not withstanding, the experience he had with the TKO and Tremec Customer Service has not changed apprecibly today.

It is only because buyers wanted to believe their treatment was not the norm that Tremec got away with this kind of customer service for so long and has been able to prosper despite the poor customer service. Buyers today have choices, more so than in the past and it is to their advantage to explore them.

The strongest message you can send to manufacturers like this is delivered with your money and shoe leather — especially in times like these.

Ed

Quote:

Originally Posted by eschaider (Post 1486246)

Do you have a design drawing and price?

Ed

Not yet, basically it will be a exact replacement with a clip holding the finger to the rail. { Just like the new tkx} Instead of the roll pin. The new design will allow more material to remain in the rail; hence making it stronger. I am open to suggestions trying to keep it simple and low cost.Just want to make it worth my friends time and seeing what type of interest.Maybe even sell to silver sport or hanlon or some of the other premiere Tremec dealers . I do not know if this will fix the problem honestly but it seems a step in the right direction. Unlike the left direction everyone seems to be going:JEKYLHYDE

Very informative and entertaining. I wound up cryo gears and updating internals on a T-5 because 2 to 3rd gears failing. It was close to speed shift but a hard shift. Eight years ago. Seriously wanted to put in tko 600 but saw all the issues people were having so went the route i did.
What about the Richmond Street 5 speed instead of the tko? What would the drawbacks be? Not enough knowledge of both to determine. Thanks

Well I was thinking those of us who already have the tko 600 and maybe even your t-5 .not sure if it has the same rail as the 600. All I am saying is it would be a low cost alternative for a chance on a better transmission. It would certainly be a big middle finger to Tremec for not fixing the issue. Trying to drum up some interest here starting to think maybe this is why tremec just chose another direction.

Quote:

Originally Posted by hauss (Post 1486286)

Hauss,

A good machine shop or machinist should understand better than me what I'm about to say.

You have to do more than just grab a piece of steel and make it the same size and shape of the original piece. It can be done and engineers reverse design parts, for equipment that is no longer made, every day. I'm not trying to discourage you, rather trying to save you from having to do this 3 or four times to get it right.

There are many grades or types of steel. Any steel can be hardened by heat treating or ion nitride hardening. Harder is usually stronger, but more brittle. Hard steel is difficult and costly to machine, so a milder steel is preferred to machine and then harden it for strength and wear resistance. Heat treating causes shape changes, especially if not properly stress relieved. Nitride only heats the metal to 900 deg so dimensions are more stable. Heat treating can harden deeper than Nitride hardening.

When tooling is used to cut steel it leaves sharp micro cracks on the surface. Normally not a problem for soft mild steel that will not be hardened and not repeatedly cycled in heavy load conditions. These micro cracks are crack propagation points - kind of like a stone ship in a windshield. Machined areas should have the finish ground to remove the micro cracks. Polishing is needed for harder steels. Also there should never be a sharp corner - perfect 90 deg change in direction. These should be radiused. The corner should have a minimum of 1/16" radius for most stuff. Some applications 3/16" or more.

Start by doing a hardness test of an existing broken shaft. Also try to identify what the steel is.