Verdict on current TKO 600 Transmission?

[eschaider]

The reduction is gear tooth face is linear with the reduction in torque capacity. Given a 10% reduction in tooth face then you get a 10% reduction in torque transmitting capacity, a 20% reduction will provide a 20% reduction in torque transmitting capacity. There is no second or third order function describing the gear's transmission capacity.

It is both true and troubling that the failure may have occured even if the gears were properly aligned. This is associated with the original designer's margin of safety that he designed into the box. If it is a 600 lbs-ft rated box with a design safety factor of only 2x or so, it is probable the gears would have broke anyhow. Interesting thought to ponder!

The strength of the gears absolutely includes the center to center distance in the calculation. In fact that is one of the parameters I mention in the paragraph where I describe the strength parameters.

By the way Tremec advises me the lateral displacement from edge to edge on the two gears is 0.149". If you look at Greg's (Fordfan) entry in TKO warning post #168 he measures his misalignment at 0.140". Here's the math from my post #169:

"The pictures fooled me. I measured the countershaft gear at 23.5mm wide (0.925")in the photo and the mainshaft gear at 28mm wide(1.10").

If we use your measurements and assume the wider gear was the correct design width then the .975" wide gear has only .835" of face width in contact with its mating gear. The transmission's torque capacity in third gear would then be (0.835/1.01)*600 or 496 lbs-ft.

I used 600 lbs-ft as the transmission torque capacity because that is what Tremec advertises on their website http://www.tremec.com/English/products/TKO.asp"

The bottom line on this is uncomfortable. If you own a TKO 500/600 you have a built in design error that will cost you third gear if you produce somewhere north of 450 lbs-ft of torque, hook up in third and execute a clean, fast gear change from second to third. The shock loads will exceed the transmission's load bearing capacity. This is not complicated.

If you don't own a Tremec and produce these power levels don't get one. If you do own a Tremec and produce these power levels, welcome you have joined those of us who were snookered by Tremec - you're in good company. We have to find a way to correct the problem or replace the transmission with one that is properly designed and performs as advertised.

It would be nice if Tremec would comment on this publicly and say something like we have a fix for you guys that have done so much business with us.

Ed

[Eliems]

In reading other threads, I notice lots of people with 15,000 plus miles on their TKO and no issues. I really like the way mine shifts! I am running somewhere close to 500 hp and I am not driving like an old lady either (although I have often taken it to church), with no trouble at all.

I expect that this is coming down to some (not all) transmissions failing under race conditions due to defective composite as well as design faults. If the TKO failed all the time when exposed to 500 ft/lbs and clean shifted into third, this would be a recall or consumer warning issue.

[eschaider]

Maybe it is!

Ed

[craigayl]

Following up on this topic, a friend with a Superformance, and RDI 427 (stroked 351w) and a Tremec 600 offered up his transmission for an investigation.

This is that investigation; http://craigayl.home.comcast.net/600/

Following up on the 3rd gear alignment, I called http://www.ddperformance.com/ . D&D acknowledged the misalignment, but said that they had only seen one failure and didn’t think it was a problem. They also said that they did not know of Tremec making any changes to correct the misalignment.

So where are we??? Is it problem?… It certainly was for Fordfan. No doubt the transmission would be way stronger if the gears were properly aligned. I guess if Tremec is not going to correct it, we will just have to wait and see. One thing is for sure though. If you do find yourself in this unfortunate spot and your dealer wants to deny responsibility because they claim you missed a shift and engaged the gear only halfway and upon releasing the clutch, caused the gear teeth to fail? You may want to consider some professional help….

BTW.... Excellent input by many on CC

Craig

[Excaliber]

Even if the gear misalignment is not a problem, it sure has led to a lot of 'bad press' and 'paranoia' at the very least. Well, the truth, whatever it is, must come out.

[Anthony]

Because of the misalignment, one edge of the tooth extends beyond the end of the corresponding tooth on the corresponding gear. I would think the tooth that overlaps the other tooth would be slightly stronger at that location, due to lateral support of that part of the tooth extending beyond the other tooth that ends up short.



If you look at the picture,

The leading edge of third gear seems to be positioned behind the leading edge of the countershaft 3rd gear, and therefore at this location, the tooth on the countershaft would be alittle stonger than the tooth on third gear itself, and since the trailing edge of 3rd gear extends beyond the trailing edge of the courtershaft 3rd gear, the tooth on third gear is likely a little stronger than the tooth on the countershaft gear.

I think this may explain the failure pattern. Why the teeth on the front aspect of third gear failed, and the rear of the teeth on the countershaft gear failed.


Interesting.

[craigayl]

Exactly Anthony.

It's not just the reduced contact area that can cause a failure, but the fact the edge of the main shaft gear tooth is subjected to greater load by the countershaft gear that is applying load 1/8" in from the edge. 1/8" in from the edge the tooth is much stronger.

This is why I wanted to capture the ware pattern on this 600 http://craigayl.home.comcast.net/600 (second picture from the top) While it has not failed, the front edge of the teeth are clearly under excessive load. The transmission would actually be stronger if the gears were machined down to eliminate any overlap

Craig

[scott coyle]

You guys are making this way to complicated. The tko 600 that broke was in a heavy car with lots of traction, the tranny simply could not get out of the way as there was too much mass, a big spread from second to third, and the over all gear was not low enough. The cobra, because of its light weight will get out of its own way even with a ton of traction. The tko and 3550 are pretty stout also, just a bit less than the 600's.

Scott

Scott

[Excaliber]

An excellent point Scott, the tranny should be fine for a 'light duty' application such as a Cobra.

[Jimi G]

One point everyone is forgeting is that Fordfan's car was a very heavy Mopar, had drag slick on the vehicle, and he had a very aggressive Spec 3 clutch installed in his car. Tremec does not recommend Spec 3 clutches for there transmissions because they are just to aggressive. All of these factors lead to the failure, not the gear alignment. Tremec tested the TKO600 in the factory and it took well over 1100 ft lbs of constant torque to cause the unit to break. As for the "light duty" comment, I have personally sold and installed these transmissions in 55-57 Chevy Belairs, all years of Camaros, Mustangs, Cobras, Pick ups, 32 Fords, 23 T-bucket, all years of Corvettes, all years of Chevelles, Impalas, Farlaines, Panozs race cars, and alot of those cars see the track on a regular basis. This transmission is not designed for heavy competition drag racing, it is designed for street driving, that is why Jerico's, Lenco's, and all the other racing style transmissions are 2-3 times the price of the Tremec TKO600. Guys Tremec is trying to supply the market with an affordable option to the higher priced alternatives I named above. How many cases of this failure have you guys ran into, I bet you can count them on one hand, maybe even one finger. It all really boils down to this, Fordfan's application was not best suited for a TKO600, and if he would tried to purchase one from me I would of explained that to him. It's not always about the sale, you have to make sure it best fits the needs of the customer. As for the misalignment I have been assured by Tremec that the contact area of the third gears is fine and has not compromised the integrity of there transmission. Look at how many cars are out there with a TKO600 in them, let alone how many Cobras on this site, with 20,000 or 30,000 miles on them with no problems at all, unfortunely those aren't the threads with 50-200 posts. I feel like Tremec is getting a bad rap here when all they are trying to do is offer a reliable transmission that will take alot of power, at a reasonable price to the consumer. I can tell you this, I have stated it in the past and I will say it again, for the money you will not find a better or stronger transmission on the market. I can also tell you this when I get close enough on the couple of projects I am working on there will be a TKO600 installed in them, not because i sell them, but because I deal with them everyday and I see how dependable and strong they really are. jimig@standardtransmission.com

[eschaider]

Scott,

In the case of the Cobra I think you may be correct. My underlying problem is there was nothing wrong with the money we paid for these, there should be nothing wrong with the transmission. Or, if there is, the manufacturer should make it right.

When the transmissions were purchased by each of us the expectation was for a properly designed, manufactured and assembled unit. What we have discovered is that they are not! You would not have purchased the piece if you knew it had one of the bearings it required and was designed to use, missing.

The misalignment problem is a variation of the missing bearing problem and I suspect, probably would fall into a 'defect in materials or workmanship (engineering) category' if one or more users were to begin the formal complaint process.

The increduluous part is that a factory authorized distributor would attempt to place blame for the failure on the purchaser. I would think that the manufacturer and the distributor would want to make good as quietly and quickly as possible so as not to draw unwanted attention to the design problem. Quite the opposite has occured.

The handwriting is on the wall for whoever experiences a failure next. Get ready, it is going to be a battle. I think I recall something from the oldest military treatise in the world 'The Art of War' by Sun-Tzu. In his work he teaches that the winning General will pick his time and place of battle to optimize his chance of victory.

I think we should start thinking about our time and place of battle and stop making excuses for the manufacturer, they are quite good at that. It is time to start taking care of ourselves.


Ed

[scott coyle]

Ed,

I would argue that it is properly designed, manufactured and assembled unit. I could pull apart any motor or transmission and nitpick at an assembly procedure or clearance issue. The bottom line is, does it stay together or break? Many tko 600's are staying in one piece in a variety of applications. This application simply exceeded the limit.

The handwriting is on the wall, if you experience a failure next, you too have likely exceeded the limit of the transmission.

If you are worried about breaking a tremec, don't be unless you run slicks. Lift off the throttle slightly on the second to third gear shift with slicks and you should be fine.

Scott

[undy]

The act of a missed shift, in itself, does not explain fordfan's tranny failure. But ... on the flip side of the same coin.... missing a gear, over revving the motor and "refinding" that gear at or near redline while at WOT will cause an tremendous amount of torque multiplication. In extreme cases (maybe fordfan's case???) the torque multiplication in itself could cause the failure on a set of perfectly aligned gears. I know... I blew 2nd gear on a 1 to 2 missed shift in a Richmond 6spd I had behind a 496 powered 69 Vette. Those gears had 100% contact, before and after the "customer funded" rebuild. The possibility of the transmission's 600 lbft rating may hold true, even with the evident 3rd gear misalignment. No one knows the answer on that one, 'cept for Tremec and I don't think we'll be hearing directly from them. I'm not left with a warm fuzzy on the evident uneven tooth wear though. One thing that I will say.. Third gear would definitely be stronger with 100% contact.

I'm not soliciting these alternative possibilities, just offering them up for consideration.

Frankly, I'm a little PO'd at fordfan for manipulating Kiesler through our board with ulterior motives while telling us and them lies along the way.. How many villains are there in this story???

Dave

[dlang14]

my biggest concern here as a TKO600 owner is not that it might or might not break. Sure I'd love to resolve that, but to me the bigger problem is that the Tremec rep blamed the failure on a missed shift, which from the experts here doesnt seem to be the case.

I'm willing to leave it alone if the folks that know a lot more than I do all say it'll be fine in a light car like the cobra, but if it does break, what then? Did I too miss a shift? What happens if I put on some tires that actually stick even just a little?

To me as a consumer I understand that all products have issues, some unknown and some known where the manufacturer said go ahead and ship it. The issue to me is how does that company respond when I have a problem.

Daryl

[eschaider]

Scott,

Your point is well made. I guess the part of this whole thing that makes the hair on the back of my neck stand up is the response from the distributor and apparent lack of response from Tremec. Daryl summed it up well in his post, how does the company respond when I have a problem.

Jimi G's points are also good. The unit may not have been suitable for the application. This brings us back to a distributor problem again, the distributor should have know this and steered the customer differently. He didn't. When we make choices based upon input from a trusted advisor presumably they will guide us correctly and not allow the loss of a sale to influence their advice.

For what it is worth I would not expect a TKO 600 to be close strength wise to a Jerico, Liberty, G-Force or any other race unit. That was not the design purpose and they don't cost as much! I also don't expect to have the unit designed/manufactured/assembled in a fashion (i.e. misaligned gears) that is inconsistent with industry practice for similar product or norms other manufacturers and Tremec typically adhere to in their other products.

The fact the distributor recommended it and sold it knowing the application and the lack of suitability, in fact made a special kit for the application, speaks volumes about the distributor. To later blame the failure on the customer begs the question what's wrong with this picture? I'll give Tremec the benefit of the doubt and say they didn't come up with the same failure analysis as the distributor. But, they have been unnecessarily quite and absent from the problem resolution process.

Still, no good feelings on these issues.

Ed

[Anthony]

Originally Posted by scott coyle

You guys are making this way to complicated. The tko 600 that broke was in a heavy car with lots of traction, the tranny simply could not get out of the way as there was too much mass, a big spread from second to third, and the over all gear was not low enough. The cobra, because of its light weight will get out of its own way even with a ton of traction.

If I remember correctly, you ran a tremec in your cobra, and had recurrent problems with it, rebuilding it maybe 2 or 3 times. Then you got a jerico, or something like that. I don't think the tremec is as strong as what it is marketed to be.

Originally Posted by Jimi G

As for the "light duty" comment, I have personally sold and installed these transmissions in 55-57 Chevy Belairs, all years of Camaros, Mustangs, Cobras, Pick ups, 32 Fords, 23 T-bucket, all years of Corvettes, all years of Chevelles, Impalas, Farlaines, Panozs race cars, and alot of those cars see the track on a regular basis. This transmission is not designed for heavy competition drag racing, it is designed for street driving

Then why is the TKO marketed as a road-RACE tranny, if it is really designed for street use? Anyways, I think the ratio's are way too wide for serious track work.

Originally Posted by Jimi G

This transmission is not designed for heavy competition drag racing, it is designed for street driving, that is why Jerico's, Lenco's, and all the other racing style transmissions are 2-3 times the price of the Tremec TKO600. Guys Tremec is trying to supply the market with an affordable option to the higher priced alternatives I named above.

Jim, not that I mean to bust your chops, but the tremec is really not an alternative to the Jerico's, G-Force, Lenco's, because it can't take the abuse these other tranny's can.

Originally Posted by Jimi G

I feel like Tremec is getting a bad rap here when all they are trying to do is offer a reliable transmission that will take alot of power, at a reasonable price to the consumer. I can tell you this, I have stated it in the past and I will say it again, for the money you will not find a better or stronger transmission on the market. I can also tell you this when I get close enough on the couple of projects I am working on there will be a TKO600 installed in them, not because i sell them, but because I deal with them everyday and I see how dependable and strong they really are.

David Kee sells new toploader tranny's for about $1600-1800, and you can buy new muncies as well, both of these trannies would probably be in the same ballpark as the tremec in strength, and some people may think they may even be stronger.

I think the tremec is a fine tranny, just maybe not as stout as many people are led to believe.

Originally Posted by eschaider

The fact the distributor recommended it and sold it knowing the application and the lack of suitability, in fact made a special kit for the application, speaks volumes about the distributor. To later blame the failure on the customer begs the question what's wrong with this picture?

I think this says the most, that a "kit" was made to install these trannies in big block B-Bodies, knowing that these cars were meant to be drag raced. If he was running alot of nitrous or had a blower, then I would expect a possible, likely failure. I wonder if the original tranny, A-833 4 speed would have failed under the same conditions ?

[scott coyle]

Anthony,

You are correct,I did have a problem with a tremec. The rectangle detents in the syncro assembly were cracking. This would cause the tranny to hang up on down shifts. The upshifting was always fine. The new detents were free from tremec and the tranny worked well after that.

I was downshifting into second or third at 5500 rpm into the lower gear and I was not to gentle at it. I don't think the tranny was designed to be downshifted at that high of an rpm into the next gear but with a red line of 8,000 rpm, 5500 or better was normal.

I decided to buy a jerrico after the downshift issues. Before I baught the jerrico, I was running at willow springs when I went over the hill (turn 6) in third gear, as I pushed in the clutch for a gear change, a giant boom sounded and it was coming from the tranny. I coasted to the pits and onto the trailor it went.

I allredy orderd a jerrico but I thought I had broken third gear for sure in the tremec. When I pulled the tranny, the motorsport clutch had exploded. The tremec was pulled apart and inspected. It was in perfect shape. I was road racing with slicks, a 675 hp, 525 ft pounds of torque motor with a 3.89 gear. I drove the tremec hard and never blew up third gear. The light weight of the car saved me, I think.

For the street, the tremec works great, for all out abuse, get a jerrico.

Scott

[Excaliber]

For the money, I'd buy the Tremec if I was going to run it in my Cobra. This is largely based on Jimi G's comments concerning price. Cost\benefit analysis if you will, says for ME, the Tremec is a good buy for my application.

[hssss]

I have been biting my tongue not saying what I really thought. I have no interest pro/con related to Tremec or Gforce BUT. When I read the start of this thread the first thing that came to mind was that Tremec was attempting to do some damage control. This is the back cover on the current KITCAR mag. I see no mention of , but only in light cars.



I then compare the responses to this post.

Originally Posted by KMAC

Kudos to G-Gorce for their awesome customer service. We just installed a G-Force T-5 tranny that they built for us and we had problems with reverse kicking out a gear as we let out the clutch. Upon contacting Bubba, at G-Force and advising him about the problem and telling him that we had two races coming up in the next two weekends that we wanted to attend, G-Force immediately started building another tranny to the same specs, and with an agreement to send back one of the two trannies once the problem was figured out, they sent it out the next day. The tranny is being sent out with the type of oil they recommend along with a call tag for the other tranny so I don't have to pay shipping to return it.

This is the best customer service I've ever experienced from any company period!!! The tranny costs approx $3,000.00 and the fact that they had the trust to immediately build and send out another one without anything in return other than a credit card number for insurance is absolutely amazing. Most companies would have wanted the tranny first, inspected it, then made a judgement on it. This is exceptional customer service. Please spread the word for they are deserving of it!!!!!

http://forums.corner-carvers.com/showthread.php?t=31831

http://www.g-forcetransmissions.com/tran_gt-5.asp

[bret a ewing]

Had one issue with a TKO 600 w .6 od. VIR 2006 open track, last day, last session.
135 miles on trans, in cobra. 25 track miles prior to failure.

To preface, 1/2 the time I could not catch reverse on the first direct engagement try (push right/pull back). Had to row neutral a couple of times and slot 5th, before rev would mesh. Figured the quirk was the new box not fully broken in.
Anyway, on the grid, the car in front of me could not get started. Went to back up and go around (I was excited so I was pretty aggressive with my shift) and "POP". Cracked the linkage between 5th and rev. (Looks like a mini connecting rod). After analyzing trans, linkage was not adjusted properly. Blocking pin hung up.

Ordered new trans - TKO 600RR, under warranty, had it torn down, re-shimmed and readjusted by my local tremec rep.

Smooth as silk, no problems so far, 1000mi. Satisfied with performance.