frankenstangsghost
frankenstangsghost New Reader
1/20/12 8:52 a.m.

Weren't we just talking 'vettes? Here's a cheap C4 near me, if anyone is interested: http://fortcollins.craigslist.org/cto/2808001581.html

Gearheadotaku
Gearheadotaku GRM+ Memberand SuperDork
1/20/12 2:13 p.m.

could be a good deal. Good thing it's not closer, I'm out of room.

cwh
cwh SuperDork
1/20/12 3:20 p.m.

That's quite close to challenge cost.

Aeromoto
Aeromoto Reader
1/20/12 7:58 p.m.

I had one of those back in the day. Those 4+3 transmissions are some of the worst contraptions ever concieved by modern man.

Gearheadotaku
Gearheadotaku GRM+ Memberand SuperDork
1/20/12 9:13 p.m.

My 4+3 was fine.

Aeromoto
Aeromoto Reader
1/20/12 11:02 p.m.

My 4+3 sucked. Used to break shift forks like they were made from candy canes, and the o/d unit blew up at least 3 times.

mmosbey
mmosbey GRM+ Memberand Reader
1/21/12 9:11 a.m.

Ok. Two things I hear talked about, generally with anger, but that I don't "get" and haven't had the chance to experience first hand are 4+3 and skip shift.

What does this stuff do that makes driving a vette with a stick different than, say, something straightforward like a Miata?

WilberM3
WilberM3 Dork
1/21/12 12:41 p.m.

skip shift as i understand it is a solenoid that is actuated based on throttle position and vehicle speed that prevents you from shifting into 2nd from first, but rather kicks it over into 4th directly under lightish acceleration. heavier application of the throttle deactivates it. it's easily removed though.

mmosbey
mmosbey GRM+ Memberand Reader
1/21/12 1:22 p.m.
WilberM3 wrote: skip shift as i understand it is a solenoid that is actuated based on throttle position and vehicle speed that prevents you from shifting into 2nd from first, but rather kicks it over into 4th directly under lightish acceleration. heavier application of the throttle deactivates it. it's easily removed though.

That does sound annoying. So, is there some spring or something so the move to 4th feels natural? Having had a car with a slightly out of nick shift linkage that made certain shifts a challenge, this sounds like it'd just result in a lot of confusion and annoyance.

njansenv
njansenv HalfDork
1/21/12 1:25 p.m.

You learn to either drive around the skip shift (not tooo hard, but you end up using more throttle than you might otherwise) or defeat it (also not too hard). It was REALLY annoying before I got used to it when I just wanted second gear in order to crawl around parking lots. I can't speak for the 4+3....

Gearheadotaku
Gearheadotaku GRM+ Memberand SuperDork
1/21/12 1:38 p.m.

The skip shift thing is on the 6-speed ZF trans, 1989 and later. WilberM3's description of it's operation is correct. It's a fuel economy thing.

The 4+3 was used from 84-88. A regular T-10 4speed was bolted to an external overdrive unit. They did not share fluids. The O/D would shift in and out on it's own unless you pressed the button to turn it off. This was the trick to using it.

When driving around town or on the track I'd turn it off an have a 'regular' 4 speed car. Once on the freeway, or sustained hi speed, push in the clutch and hit the switch. It could be shifted without using the clutch, but doing so took the strain off it and greatly extended it's life.

It was built like a little 2 speed auto. Clutch packs, pump, valvebody, serviceable filter and pan. I changed to fluid and filter every year and never had a problem with it. Won many autocross seasons and even drove the Silverstate classic with it. Granted, it was bad when I bought the car, so I had a fresh start with mine.

The Calloway Turbo Vette's used these units, so they can take a good amount of power, but they need proper care and feeding, plus are berkin' heavy when bolted to the trans...

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