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Old 12-12-2018, 01:08 PM
KyleJones KyleJones is offline
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Default TKO 500 Faceplating worth the 50lb penalty?

Hi Everyone

I'm looking for some transmission advise. Currently I'm running a TKO 500 that I can't shift 2->3 at 6500 to 6800 RPM. I've upgraded to carbon lined synchros, verified specs for endplay ect. and even replaced the shifter with no luck in fixing the problem. Maybe I have a bent fork or something else 'simple' that will correct my problem, I don't know.

Anyways I'm thinking of having Liberty Gears rebuild it and "upgrade the internal shift linkage" but for $300ish more they will face plate 2-3-4. My questions are: Is it worth the 50 lb weight penalty and is this the right box to face plate? Looking at car weights it appears that Andy doesn't run dog rings but Heinricy does... overall FP cars are maybe 50/50 on running some sort of dog ring engagement?? Since there isnít a consensus, what are your thoughts on dog ring vs. synchro shifting?

Also, am I missing the bigger picture? Is there a better solution than the TKO? I've done some drive force analysis (at least the best I can without real engine dyno numbers) and I'm convinced that I want to run a 5 speed especially considering I have my eye on Road America runoffs in 2020. But maybe I'm wrong and 4 speed is the way to go.

Appreciate any advice you may have.
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Old 12-12-2018, 03:08 PM
smithpr smithpr is offline
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Great questions. When you say you can't shift what does that mean? Can't get out of gear? Comes out of gear but doesn't go into the next gear?

Help me understand what is going on?

I run the Hewland/Midvalley dog box. Very rugged and always is willing to shift no matter what is going on. That can be good and bad.

I ran a bunch of different T-10s and they always shifted. My issue was the fact that they tended to break and it was easy to "take the syncros out" on the downshift.

Looking forward to more discussion.

Philip
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  #3  
Old 12-12-2018, 04:20 PM
KyleJones KyleJones is offline
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It felt like I was shifting into nothing... if that makes sense.. talking to the guy at Liberty I understood that the 1-2 rail may be getting caught up in the shift to 3rd and that their solution helps prevent this. I tried to be real careful on my shifts but the only way I could get into third was wait for the the revs to drop.

Also I has some issues with it popping out of 3rd on downshifts. Probably a rev match issue on my part but also maybe related?

As such I've been starting races in 3rd gear which is way too tall:

https://www.youtube.com/watch?v=jOb9KYlnE4s
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Old 12-12-2018, 05:15 PM
KyleJones KyleJones is offline
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Quote:
Originally Posted by smithpr View Post

I run the Hewland/Midvalley dog box. Very rugged and always is willing to shift no matter what is going on. That can be good and bad.

Philip
If you don't mind me asking what final drive do you normally run? And do you use first gear assuming it's close to 2.5
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Old 12-12-2018, 06:38 PM
smithpr smithpr is offline
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I run a 3.73 everywhere but Daytona. I could likely run a 4.11 at MO but it would add a bunch of shifts so not sure it would really be faster.

I think that there is something going on with your transmission. When you say it goes to nothing does that mean the shifter moves its full motion and you let the clutch out and nothing happens or do you mean it "won't" go into gear and when you let the clutch out it is in neutral?

Let me know.

Philip
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Old 12-12-2018, 07:37 PM
KyleJones KyleJones is offline
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Yes, feels like I'm putting it into gear (shifter moves forward) but when I clutch out it's in neutral. From reading forums I've seen several stories like this guy's:

https://www.w8ji.com/tko_600_shifting_problems.htm

Which led me to Liberty Gears to see if they could solve my issue.
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  #7  
Old 12-13-2018, 01:24 PM
smithpr smithpr is offline
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I am not a transmission expert and I have never rebuilt one. My experience is what you are dealing with is a result of the syncros not being able to align the teeth on the sliders and the gears. It is an issue with almost all sycro boxes. Shifting a bit slower helps and I think finding the right person could help solve your problem. I have never had this happen with a T-10 but my muncies have been notorious with this issue going from 1st to 2nd.

This will not happen with a high-quality dog box. Remember due to the much heavier rotating mass of most dog boxes they do eat power.
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Old 12-13-2018, 06:36 PM
MLong MLong is offline
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In regards to the dog box, the biggest Pro to that type of box is the durability. Unless you are very bad at shifting and beating up boxes, a Jericho or Mid-Valley box will need very little maintenance for a couple of seasons. They are made to take the abuse of road racing, and taking in consideration the costs of buying a "built" synchro box and maintaining them, the dog box could be the cheaper option.

I don't believe the 50 lbs penalty for the dog box is justified any further now that there has been sufficient time passed by. The dog boxes are not a true shiftless box with the specified gear sets that are required. The ratios are spaced to far apart, and will still require usage of the clutch (for durability reasons). As Philip said previously, the heavier rotation mass of the dog boxes will negate any power transfer gains from the straight cut gears.

With all that said, we do run the dog box mainly for the sole purpose of piece of mind that it won't fail.

I have experienced what you are going through and found that it was more a timing issue of the shift with rpm's and clutch action, but that was with a stock box.
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  #9  
Old 12-13-2018, 10:55 PM
KyleJones KyleJones is offline
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Thanks for the info guys, this is helpful. If I were to pick up a dog box I see a lot of used Nascar transmissions like G Force GSRs for about $6000. Is that a good way to go? I can't find much on static weight, how much does a typical dog box weigh?
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  #10  
Old 12-14-2018, 10:24 AM
jimwheeler jimwheeler is offline
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I have a Jerico dog box and a Muncie, both out of the car. I'll see if I can get the time to weigh them in the next day, or so. They are in shipping boxes, so the weight will include the box. P.S. I have run them both and will be putting in the dog for 2019.
wheel
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