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Discussion Starter #1
Long time no post, I've been kinda letting the car sit while I gathered money. Still not rich enough for a rebuild, but I'm working on it and had some new developments occur.

So about October last year, started having some trouble with the t56 rubbing into 4th gear. There was no noise, it was just a little stiff going into 4th. We flushed the trans fluid twice, because I accidentally added some of the wrong fluid the first time. It helped for a bit, then started up again. We discovered a leaky slave cylinder, and after repairing that, my clutch was hanging to the floor, turns out it was a bad master cylinder too. So we replaced it, and bled the clutch too, just to be sure. On the test drive after the master cylinder install, the car ran perfectly for about 10 miles, then locked itself into 4th gear. We towed it home, and there it has sat since (about mid November). Well, we've run the car about once a month or so, since it'll probably be sitting for a long time. Every other time we ran it, I tried to see if it would budge out of 4th, but no luck until about 2 weeks ago. It was warm, probably warmer than any weather we'd had since September of last year, and I didn't even intentionally test the gear. I just rested my hand on the gearshift and it popped into neutral. We ran through and tested to see what all the tranny would do, and here's what we found:

It will sit in neutral fine, and will go into 2nd with minor rubbing (no noise). It does not fully engage into first and acts like something is blocking it. It also will not let you move the gearshifter to the right in order to reach 3rd, 4th, 5th, 6th, or reverse at all. Feeling accomplished, we shut it down for the day.

A few days ago, I couldn't resist, and so we ran the car again. It was in neutral, and so I revved the engine to 2500, 3000 RPMs (foot was off the clutch). When the RPMS slowed down to idle level, you could hear some chattering noise. I put my foot on the clutch and engaged it, the chattering stopped. It did not start up again when I removed my foot from the clutch. But, as soon as I revved the engine a little bit again, the chattering started again. IDK if it is significant or not, but the weather that day was a good 10-20 degrees cooler than the day it popped into neutral.

I'm fairly sure that the 3-4 shift fork has an issue and is causing the inability to move the gearshifter, but am now confused about the chattering. That never existed before. The clutch is pretty new, about 3,000 miles on it. Any ideas on this?
 

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It could be broken pieces rattling around in your transmission. To clarify, when you press the clutch pedal in you are dis-engaging it, and it is engaged when your foot is off the pedal. When in neutral with the clutch engaged, gears 1-4 and R are all spinning inside the transmission.

Of course it is possible that it is clutch related too, but with all your transmission woes my money's on it being the culprit.
 

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Discussion Starter #3
Thank you for your advice. I finally found about 10 or 20 forum posts (other forums) with the exact same symptoms I had, turns out it was the 3-4 slider keys that broke. Good to know. You think if I drained the tranny and it was the slider keys rattling around, that they'd come out? Just curious...

Oh and I noticed you have the viper 2nd gear and mainshaft in your t56, was it worth it? What are the benefits of cryo-treating the internals? Is cryo different from micropolishing?
 

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While the keys are a very possible cause of your problem, it also could be a broken fork as well. You just can't know for sure without disassembly. You may be able to get it out by draining it, but it's not going to solve your problem. There are two strong magnets located in them main case close to the drain plug that will catch any broken steel parts. If it is in fact a broken key, the magnet should easily catch it before it exits through the plug. If, however, it was a broken stock 3/4 shift fork, it wouldn't be caught by the case magnets as it's made of aluminum and would be free to rattle around the transmission.

It's hard for me to say if any of those mods are worth it or not. It certainly gives me more piece of mind, but it's something you'll never be able to feel (or measure for that matter). I had to replace my mainshaft anyway, so the $600 price tag for the Viper mainshaft, slip yoke, and machined tail housing wasn't so bad considering I needed to at least buy a $250 F-body mainshaft anyway. The upgraded 2nd gear just made sense as it would have been a glaring weak spot with all the other upgrades.

Cryogenic freezing is a somewhat controversial process which brings the temperature down to near absolute zero temperatures, which will increase the martensite crystalline structure (a harder crystal structure of steel) by changing some of the remaining austensite crystalline structure that remains at room temperature from the normal cooling process of steel. The result is a harder steel which resists surface fractures.

This differs from finishing processes, such as REM and Mikronite, which finish the surface of the steel to create a smoother finish. This has both a benefit of reducing friction (less parasitic drivetrain losses and heat), and further reduce microscopic peaks and valleys where stress fractures can start.

I must say that for most people these processes are probably not worth the money. I have no way of telling if these things even did what they were advertised to do and with the torque levels of most builds the regular machined T56 parts are more than adequate.
 
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