The Eliminator

Can the CAGS, Ditch the Skip Shift--and Have Some Fun with that Six-Speed!

Bob Wallace Oct 10, 2002 0 Comment(s)

There aren't many things to find fault with on a C5. Even the standard-geared automatic convertible (the heaviest and least "sporting" Fifth-Gen.) will handily blow the doors off nearly anything else on the road. The handling ranges from very good with base suspension and run-flats, to slightly beyond superb in a Z06. Yeah, they could (should?) be even faster, and some of the small bits and pieces show the car's common ancestry with other Chevrolet products, but there really isn't much to carp about. Except for......the blankety-blank, expletives-deleted CAGS (Computer-Aided Gear Selection), more commonly cursed at as the skip shift.

This abomination was concocted by GM engineers and first installed in the '89 six-speed Corvette along with the ZF gearbox.

Today it is still part and parcel of every manual transmission Corvette. Its intent was--and still is--to make it easier for stick shift Corvettes to meet or exceed federally mandated emissions and CAFE (Corporate Average Fuel Economy) requirements.

The CAGS forces the transmission to go from First directly into Fourth during relatively light-throttle, low-speed driving--exactly the sort of conditions you'd experience in normal stop-and-go, rush hour commutes. You can beat the skip shift by short shifting from First to Second before the car reaches 15 mph (just barely rolling) or always wind up to at least 20 mph before making that First-to-Second shift. But if you try to make a First-to-Second shift between 15 and 20 mph, at the same time that an idiot light in the tach glows with a message reading "1 TO 4 SHIFT," the lever goes directly into Fourth and your usually potent C5 acts like you'd just driven into a wall of pillows.

A solenoid that is mounted on the transmission case and tied into the car's PCM (Powertrain Control Module) controls the CAGS True, you can simply unplug the solenoid from the harness. That will bypass the skip shift function--and can (not always, but quite possibly) make the PCM go totally bonkers. Or you can do what we did on Tony Correia's six-speed '99 ragtop.

Tony had whined a little about the skip shift, but not a lot--until after he and I had installed a Hurst short-throw shifter in the C5 (see Shifty Business Part Two...Hursts So Good in the November '02 issue). Then, suddenly, the shifting was a lot more fun and the skip shift seemed a lot more intrusive. He was so pleased with the shifter that he went back to the Hurst catalog and ordered their newly-released C5 Skip Shift Eliminator Kit, PN 155 0120. (There are some other skip shift eliminators available, we haven't had the opportunity to try any others but assume they all work in a similar fashion. None that we've seen cost more than around $30 plus tax and/or shipping.)

This is about as simple an item to install as you could imagine. It'll take more time to disconnect the battery ground, or jack up the car and rest it safely on jackstands than to install the Skip Shift Eliminator.

In less than 15 minutes, from start to finish, we ditched the hated skip shift feature, without causing any miscues to the PCM. Tony can now shift his C5 six-speed from gear to gear, at any speed he wants--no short shifting or holding in First to over 20 mph in slow traffic, and no more swearing at the car when it tries to control the way its driver wants to drive. The "1 TO 4 SHIFT" idiot light still comes on, but who cares! The CAGS Skip Shift Eliminator Kit is a simple fix, and an already great driving car is now even better.

8

The six-speed gearbox, which bolts directly to the differential in a C5, is well hidden from view. But this drawing, looking forward at the transmission and diff from above and to the left, should give you a clear idea of the skip shift solenoid's location. While it is hard to see, it's quite easy to access.

Here's Hurst's PN 155 0120 CAGS Skip Shift Eliminator Kit. The light white piece in the right hand of C5 owner Tony Correia plugs into the skip shift solenoid while the original connector that went into the solenoid will be plugged into the larger, dark (it's black) part. These are modified OEM connectors and are fully sealed, so there will be no problems with either fit or exposure to outside elements.

After disconnecting the ground from the battery and raising the car aloft (we used a hoist to make it easier to photograph, but this can be done with the rear of the car resting securely on a pair of jackstands) Tony unplugged the harness connector (right) from the skip shift solenoid and replaced it with the sealed-end replacement.

All that remains to be done is to secure the bypass connector to one of the steel lines beneath the car to keep it from hanging loose and possibly getting damaged. This view is looking straight upward. The capped off solenoid is to the right (arrow) and the bypass connector and harness are at the left (arrow) toward the front of the car. With everything done underneath, we dropped (just kidding) the C5 onto the floor, hooked up the negative lead to the battery, and headed out for a test run.

Tony intentionally took the car up to about 17 mph--with the "1 TO 4 SHIFT" light aglow--pushed down on the clutch and pulled the shifter towards Second--and it slid right into Second, just like we wanted, time after time! Who cares about an idiot light, we've ditched the skip shift!

COMMENTS

subscribe to the magazine

get digital get print
TO TOP