Skip Shift Can Be Useful!!!
 

Several months ago I posted a question asking if the skip shift solenoid could be used to prevent a 3-2 downshift. I got several responses which ranged from why - no – maybe and yes. The reason I wanted this functionality was that while racing I have accidently hit second instead of fourth gear. This has always resulted in a major over rev condition and each time I pulled 2 studs out of the head (iron headed Impala motor) but could have easily done more damage elsewhere. With my new engine I am using screw in studs with the aluminum heads so I would not have this problem - BUT with as much money as I have invested in the new motor, I would hate to break it over something as stupid as a missed shift.

Now on to the modification... What I did was modified the skip shift lever to my own liking. The way it works is that will I will use a window switch to power the solenoid at a specified MPH. With the T56, 27 inch tires & 4.10 gears I should never be in second gear at anything over 80 MPH. I just need to find out the number of pulses coming out of the VSS at that speed and apply the appropriate “chip” in the MSD window switch for it to block out 2nd gear. Sounds pretty simple – even for a guy like me. Now onto the pictures.

Here is the stock skip shift lever:
http://home1.gte.net/bristra4/ArchivePics/01SSL.jpg

Here I ground off the tab that would ultimately block 3rd gear also if the solenoid was powered.
http://home1.gte.net/bristra4/ArchivePics/02SSL.jpg

This shows the new configuration of the skip shift lever. When comparing it to the original you can see how it works – pretty simple. I just welded/filled in the areas that needed to be done and then ground it down to form it.
http://home1.gte.net/bristra4/ArchivePics/04SSL.jpg

The original location for 4th gear had a “divot” so I made the same for neutral and 3rd.
http://home1.gte.net/bristra4/ArchivePics/05SSL.jpg

Here is the lever in action. This picture is taken with the shifter in 1st/2nd gear.
http://home1.gte.net/bristra4/ArchivePics/06SSL.jpg

This picture shows the solenoid powered which is blocking any attempt at shifting into 1st or 2nd.
http://home1.gte.net/bristra4/ArchivePics/07SSL.jpg

It will be a bit before I can actually try it on the street. What was nice was that the lever could be accessed by only pulling the tail shaft housing and the little fill panel on the top of the transmission. I am actually thinking about doing the same thing to block out 5th & 6th as I should never have the need to go into 5th at the drag strip. My 4400 lb Impala would never hit over 125 so there is no real need to even have access to 5th gear.

Open for comments….
TOM B

Now if you could do this to prevent a 2-1 shift I would be all over it! Im surprised you are missing 4th...generally that is easy for me??? Its 2-3 that I ****ed up.

It could be easily done. All it would take is to lock out 1st gear by using a ramp similar to what they used to force you into 4th.

I got to talking to a buddy and he gave me a great idea. Since I would only use this when racing I could wire the solenoid to a switch. I could turn it on as I lined up and the piston would ride on top of the 1/2 gates. When I eventually shift into 4th the piston would "fall" into the 3/4 gates. To take it 1 step further I could build another wall to hide the 5/6 gates a little higher than the 1/2 and would never have to worry about accidently hitting 5th gear instead of 3rd... hmmm......

TOM B

now your taking all the skill out of driving a t56:D

I know driving a stick requires "skill" but I am lacking in that department from time to time. My wife has taken it down the track a couple times so I always worry about the car... I mean my wife's safty. Besides, someday when my son takes it out for a drive I can lock out 5th and 6th so at least I know his speeds will be under 125mph ;)

Well - I took it apart over the weekend and added a wall to block out 5th and 6th. The picture below shows the new configuration.

http://home1.gte.net/bristra4/ArchivePics/08SSL.jpg

And here is it in action.
http://home1.gte.net/bristra4/ArchivePics/09SSL.jpg

I think I am going to like this. I can now be forcefull with the shifts and not worry about missing them. Now I will just come up to the line, turn the switch on and race. At the other end of the track I can flip the switch off and it will be business as usual.:cool: