I posted this on another forum (title-Shimming detent) back in 8/05 (http://www.z06vette.com/forums/showt...etent+shimming) with over 6300 hits. There were some naysayers but many more props. It is cheap way to tailor the shift effort on the C5 six speed for sure and may work on other models. It takes longer to put the car on jack stands than to complete the Mod.

Happy modding!
Pictures of the real thing
Passenger side of trans

With detent removed

Detent and shim

Somebody commented on losing the ball when they removed theirs. Not on this 2004 type it is a assembly.

 

Do you have any trouble with the transmission popping out of gear with less detent force?

 

done this many times... no problem with popping out of gear and it does make a short throw much easier to deal with....

 

I did this to my car in 2005 and have never had it pop out of gear. There is many people that use this mod after I posted it on the other forum. The cool thing is you can tailor it to your liking. I just didn't like the amount of effort it took to shift after I installed my short shifter.

 

Ahhhh yes, the Anti-Venom Mod.

 

Seem to remember some who had used thicker than the .070 shim to lessen the detent even more. Does excessive thickness cause shifter rattle or reduce the force so much as to make inadvertent shift into reverse possible?

Charlie

 

I had problems with the way my car was shifting and came up with a way to make it better. I then posted it (http://www.z06vette.com/forums/showt...etent+shimming) on another forum. No disrespect intended but Anti Venom was marketing a Mod that I guess replaced the dentent assembly, which would cure the same problem. My fix was about $59.00 cheaper and a trip to NAPA was the shipping time/cost.

This mod will not make you miss a gear or shift into the wrong gear. It simply lessons the effort to get through the gate. If your going to miss or hit the wrong gear you were going to do it anyway. LOL

I just now decide to illustrate the mod which was only in text up until now.

I like some feel going through the gate, so .070 was good for me with my short shifter. I have read where some people have put more shim in and that's what they like. You could put to much shim in and that would cause you problems. The detent helps hold the gear your in. So again start out with .050 and work up to you get the feel you like.

 

Just wondering.....Have you actually rebuild a manual C5 tranny? It's been my understanding that the only purpose, of the ball and spring, is for the neutral detent only....and has nothing to do with detent force in a selected gear. I do have the overhaul manual, and cannot find a picture depicting the rod with detents shown in your initial post.

Thanks in advance.

 

No I have never rebuilt a T-56 but I did stay at a Holiday Inn Express last night so I probably could. LOL My manual does not show a good quality picture of what your asking for either. But I have done other transmissions and there is normaly a dented "cut out" in all gears including N and R. Some even have the "cut out" at different depths.

 

So based on your drawing, you are assuming this is how it looks, and you are assuming that your understanding of the operation of the shift detent is correct?

 

That is the way it looks. It isn't his drawing, so no assumptions are being made. Whether his understanding of the operation of the shift detent is correct or not, the modification works and does exactly what he said it does. Why the attitude for someone who is trying to help?

 

I'm trying to gain an understanding, if asking questions is attitude, then I'm guilty as charged.

I'm glad you responded though, as it seems you have rebuilt a C5 manual, and can confirm the shift detent engages the rod as depicted in the first post.

 

No I haven't and you're missing the point. It matters not whether the detent functions as the OP shows or if there is a little midget inside the transmission case that throws a switch. Put the washer between the bolt shown and the transmission case and the effort needed to shift, especially into reverse, is reduced.

Charlie

 

I guess I am missing the point....I'm just not real sharp when it comes to all this mechanical stuff.....

 

My bad. Now I'm the one copping the 'tude.

If one cannot go another day without knowing more about this than necessary (that would be me), completely removing the bolt shown will reveal a spring and a ball. Remove the bolt and spring. Now go get a flashlight and start looking for the #$%^&* ball that fell out, which is not available as a repair part nor is there a ball bearing or other round, hard, spherical body available in a hardware store, the aftermarket or the after life for that matter. You really don't want to lose the ball. Don't ask how I know.

My buddy put about .125" of shims (two of them) between the bolt and the transmission case. This is a clear case of too much of a good thing is exactly that. Shifting into reverse required substantially less effort and in fact reduced it enough that once when making a spirited 4th to 5th shift he went through the neutral gate into the reverse slot. When you make a list of things never to do when driving your C5, put this at the very top. Trying to shift into reverse when going forward in excess of 90 mph makes a fearsome noise. Close second would be shifting 3rd to 4th and going into 2nd instead. That's guaranteed to make the rev limiter say "mother f....r" and bend most if not all the push rods (if you're lucky that's all it will do).

Some resistance to shifting is good. If you have to put your right heel against the shifter, brace against the door and simultaneously push with your leg and move the handle forward, it's probably too much and this mod helps with that.

Charlie

 

A basic detent is what is illustrated so people that have never seen one could grasp the function of one. They look different in many transmissions but the function is the same. It works just like your door does on any properly functioning car door. There is usually 2 step to the detent in your door, half way open and fully open. If your not sitting on a hill or the wind isn't blowing 40 mph the door will stay at the position you want. If you increased the spring rate in the door hinge assembly it could hold the door open on a hill or in wind. This may or may not help the cause.

Nothing in the drawing is to scale or replicated exactly in a T-56 transmission.

After posting on the other forum I abandoned it shortly there afterwards because so many people could not get the mechanical "detent theory" and I didn't have the time to illustrate it. I'm new to this forum and had time to draw it up so to help anybody that might want to try it but never thought they could. Most people want to understand what changes they are making to there expensive toys so not to screw them up.

So go to the auto parts store and get a couple copper or metal drain plug gaskets. The inside dia is important to fit around the threads of the cap/plug. A couple different thicknesses like .050 and .070 would be good to start with maybe even .10 also. Go home jack the rear end up, PLACE THE CAR ON JACK STANDS! Take a 15/16 deep socket and remove the plug. Cruisemon has a point, although nothing fell out of mine you don't want to lose any pieces. There are only three pieces, cap/plug, spring and ball. Now install one of the gaskets and reinstall cap/plug and tighten it up (I have never seen a torque spec on the cap/plug) so don't get crazy tight with it. Now get out from under the car and go shift through the gears. Do this until you get the correct gasket configuration and are happy with what you have.

 

And if my buddy hadn't gone jiggering around in the bolt hole with a Phillip's head screwdriver, I don't think anything would have fallen out of his either. He's just like a monkey seeing a hornet's nest for the first time. For some reason guys see a hole, they have to stick a finger or a screwdriver or something in it.

Charlie

 

If your buddy shifted into reverse while moving forward his problem had nothing to do with the detent or lack of. It was a failure of the reverse lockout solenoid.

 

Ya that's for sure. I have that illness most of the time also.

 

Didn't even consider that. I just told him it happened because he's a dumb @$$.

Charlie