[C-Spot]

Hey, another question for y'all. When I purchased my 67, I found out that the PO had put a shift kit in the C4 tranny. Since I am totally new to the technicalities of autos, i was wondering if any of you could fill me in on any info about them. Are there different kinds, or is there just a "basic" design? does it damage the tranny at all? what mechanically does the shift kit do? When you put one in, is it good for the life of the tranny? or do you have to replace things after a while?

The one thats in there now is somewhat decent i guess. it has a mild jolt from 1st to 2nd, but the conditions have to be just right for the tires (15" wheel) to chirp. I was wondering what i could do to make the chirping more common (even if its not the best for my firehawks ).

 

[Fastcat]

The valvebody is the brain of any transmission. The valve body is a complex maze if passages, checkballs, valves and springs. When a shiftkit is installed, usually nothing is done to the main part of the tranny. Most if not all shift kits only effect the valvebody. Springs are replaced with higher tension ones, checkballs are sometimes removed and passages are even sometimes blocked. All these modifications change the pressure and direction of the fluid in the valvebody. The only way you could possibly make it shift any harder without a complete rebuild would be to replace your servo with a higher pressure one... like PA Automatics. I run there's in my tranny. You could try to adjust your shift modulator (the thing in the back of the tranny that your vacum hose hooks up to). Try screwing it in or letting it out to change the rpm's at which the tranny actually shifts. Other than these simple tricks there's not a whole lot of things you can do. Buy some harder tires perhaps

Kirk

 

[Local Hero]

Fastcat was all over this. I have only a few comments to add.

Many shift kits come as a kit where you can determine how "severe" you want it to shift. The one I put in had three levels. No, it will not hurt the tranny, if anything it helps it. When a tranny bleeds from one gear to another it builds up more heat and we all know what that does. As you've found, shift kits make the gear changes much quicker. Depending on the severity, it might be a little rough on the u-joints.

I see no reason why a kit shouldn't last the life of the tranny. Although, if for some reason you decided you didn't want that anymore, I have no idea how to go about reversing the process by removing it.

One last point... for some reason, the one I put in my C6 was still shifting much sooner than I wanted it to even after adjusting the modulator. Just as a test, I disconnected to vacuum to the modulator and drove the car. It shifted just as hard and as late as I wanted so I just left it off and plugged the hose. I've been running the car that way for 8 years. I don't know if that works on a C4 though. It works great.

Mark

 

[C-Spot]

Thanks a lot guys, i love how informative this forum is. Heh, you dont know how many questions i come up with that deserve a huge "Cougar Newbie" stamp right on them.