Observations after the Antivenom shift mod, on a car with a Ripper shifter shortened 1 inch.

1. Car is noticeably easier to shift, but not "buttery" or "1 finger" smooth as some folks have reported. This is likely due to Ripper shifter, which is inherently stiffer than stock.
2. Forward-aft notchiness is a LOT less, but not eliminated.
3. Centering effort now seems higher, likely because it is unchanged and now is higher in proportion to the forward-aft effort. Revised centering springs may be the answer to achieve a better balance.
4. Shifter seems to have "play" in any gear position i.e. you can wobble it a bit. You would expect this, since the stock detent with the ball bearing tends to lock the shifter in position. The Antivenom plug has no such detent bearing. If you put a little pressure on it while in gear, you can feel the driveline vibrations. Also, you can easily slip the transmission out of gear by applying a little forward pressure on the stick when decelerating (especially in 4th gear). No biggy, since these are not things you do in normal driving.
5. It is now easier to select 4th when you wanted 6th gear, due to the decreased effort. I have "adjusted" my wrist accordingly.
6. No increase in driveline noise.
7. All in all, a good improvement. Others may achieve a similar result with the shimming experiment discussed in other threads.

Observations after installing Redline D4ATF (transmission had 24000 miles on factory fluid).

1. Slight improvement in smoothness after 30 miles. More miles may be required, although I'm not sure why.
2. No increase in driveline noise.

Hope this helps.

Jacob

 

I found this post by accident and WOW,,,I am glad that I did! Thank you guys for all of the really great info!

I want to add a few thoughts that may help clear up a few things.

First thought. There are some people who are truely having a problem with "NOTCHY" shifting issue that may be different than what we are discussing with the feel of the shifter. I believe that they are NOT talking about the detent feel but the feel that you get from the synchros not allowing the driven and engageing gear to syncronize.

The fluid in my 98 MN6 wore out and I would get that "GRINDING" feel when shifting aggresively. It was like it would skip a few teeth on the synchro and then pop into gear. I caught it early and figured out was wrong. Just changing the fluid and adding Mobil 1 Synthetic ATF made a world of difference and resolved that issue.

Second thought. For those who venture into the world of the "Afrermarket Shifter" there are a couple of things to note:

-1. Some shifters have a large bolt or screw on the front and back of the shifter body. This bolt or screw is a stop. It adjust the throw of the shift lever. The T56 really doesn't need the stop bolt because the tranny has internal stops. If someone installed your shifter for you or if you installed it and the bolt was improperly adjusted (screwed too far in) the shift lever will not be able to move the shift fork far enough and this can cause the tranny to jump out of gear. If your tranny pops out of gear and your shifter has stops, back them out and see if that helps.
The forward bolt/screw effects 1st, 3rd, and 5th. The rear bolt/screw effects 2nd, 4th and 6th. You can just see the bolts on the aftermarket shifter on the right:



-2. When you remove your old OEM shifter, this is what you will see:





The rod with the loop in the center of it, is the shift rod. It moves forward and back and also moves in an arc (side to side) Sometimes this housing and the rod get dry or dirty and the rod can hang up. That can give you a stiff notchey shift feeling also. Lubricate the rod with lithium grease if it is dry and stiff. There is also a black plastic shoe on the end of the shift rod that fits in the loop in the shift rod. If that cap breaks or wears out, it can also cause the tranny to jump out of gear because the shifter can not fully engage the shift fork into gear.

As for the OEM shifter, it does NOT have any sort of centering springs in the shifter body. If you remove the OEM shifter from the shifter housing, the shift rod will flop around like a rag doll. The centering springs are internal to the transmission. Early C5's had very weak return springs that moved the lever from the 4-5 position back to the 3 N 4 position. Later C5 trannys had a slightly stronger spring to assist centering but it still sucks. Some aftermarket shifters have adjustable return springs that make centering very positive. My Kirban is one.

As for the Antivenom shift mod, the detent is most likely there to provide a positive feel to let the driver "KNOW" that he/she is in the gear selected. As for reducing the pressure of the detent ball with a washer or going all the way and installing a plug without a detent, I guess it all has to do with personal feel. Each gear has a set of dogs that set the slider gear in place when you engage that gear. My guess is that the detent ball just helps keep the shifter handle in the gear selection gate and gives you that "yea. it's in gear" feeling. I am not a T56 tranny expert either!

I hope all of this makes sense and helps someone see what is happening inside the transmission and maybe helps them diagnosis a problem. If I said anthing to offend someone, sorry!

Bill Curlee

 

If a punk kid with hardly any mechanical experience can do this mod in 10 minutes, then anyone can. I spent more time getting the skip shift mod done.

With the copper washers I had, I doubled up and it came out to be about .125 or so of thickness. I have the BPP shifter. Feels smooth, and no problems with it holding in gear. No I just need to get some lighter springs, and I'll be happy.

 

Anyone try this mod on a C6? I don't think the trannys are that much different...

 

For anyone who has removed the stock assembly...is it possible to disassemble it and remove the spring and ball, or ist it permanently pressed together? If it is possible to take the assembly apart, does it look like it's possible to reassemble it as well?

Chris

 

Not really. It looks to have a crimped ring that retains the ball and spring.
http://www.windowdresser.net/images/washer3.jpg

Using a weaker spring was the first thing I thought of too.

Keep in mind that a 1/8" shim totally disables the detent.

 

WOW, best free mod ever! Saw this thread last night and remembered it while I was at work. We have a huge assortment of hardware at work, including 3/4"x3/32" washers I think it took me longer to actually find the bolt under there than to get the job done.

The 2-3 shift is non existant now I've always considered myself a decent speed shifter, but have missed third once or twice. All it takes is a little resistance at the wrong time and the clutch is locked before you get it all the way into 3rd. Not anymore, I just got back from a good spirited drive full of third gear chirps