Before I get the firebombs I wasn't aware of a something when I bought my C4 about the 1 to 4 light. I drove my car home after purchasing it and this light came on a couple times, but I didn't really pay it much attention, I thought maybe I did something wrong and it was a warning light to tell me I am shifting to 4th instead of 2nd as a safety thing, but after reading I realized its a EPA thing for gas guzzlers. I can't really remember if I did anything trying to force it into gear as I was quite excited and wound up after making my purchase. Does forcing it actually do damage to the tranny or just the lockout solenoid like I read? Again I don't recall forcing it, it just blinked off when I accelerated and I shifted normally. My other question is I made a small oopsie and slowing down to a rolling stop with the clutch depressed all the way I shifted to first without thinking and it made a slight grinding noise, I know shifting to first going to a stop is a no no and I am completely familiar with how to drive a manual it was just me wit my head in the clouds for a moment. Would that mistake do any damage to the synchros or anything of the such? I asked my brother who is a GM mechanic and he said I should be fine just don't make a habit of doing it frequently (obviously I knew I made an oops) I have read mixed reviews on these trans, some love em some hate em. My question is how durable are they? I hear they are quite costly to fix so I definitely want to keep it in working order. I plan on driving it strictly as a cruiser car and not hot ******* it or power shifting like a maniac.

 

you can just unplug the 1 to 4 at the tranny, tune it out or buy a shift skip eliminator.

 

The 1-4 shift or cags as it's called activates when the car reaches a temp of 120* and at certain rpms, can't recall the exact range. It didn't take me too long to learn how to simply drive around it, shift to 2nd a little quicker, or stay in first a little longer.

When it did get me, I would just hold the clutch in, shift in to the 4th position to release it and select my desired gear from there. It's really not that difficult to avoid.

 

This would be the easiest way to not have to deal with the CAGS. You can also avoid it by shifting into 2nd at a slightly higher speed. Maybe somebody can chime in with what that speed is or it will be in the Owner's Manual.

You didn't say how many miles are on the car or if you know anything about service history, but it can't hurt to do a fluid change in both the trans and the differential. Your brother should be able to get the specifics on what fluids to use.

 

If you were able to shift into second gear normally while the 1 to 4 light was on, the CAGS on your gearbox has almost certainly already been defeated by a previous owner. This would be no big surprise, as it's one thing that probably the majority of ZF-6 equipped C4 owners have done long ago. The CAGS kept the car out of gas-guzzler territory when it was new, but most owners hate it, and eliminated it soon after acquiring their cars. It was definitely the first thing I did to mine.

Live well,

SJW

 

Just to point it out, this isn't just a ZF-6 or C4 issue.
The 6-speed equipped C5 and C6 also use CAGS as does the Gen 5 Camaro.
So it's been around a long time.

 

They are VERY durable transmissions. If it works well now, don't worry about it.
If you beat on it you can break it, but they are very strong.
CAGS does go way back. In '95 i bought a Z28 new and unplugged the solenoid in the dealer lot before i drove it away.

 

I made a couple of low rpm oopsies getting the feel for it and being nervous, as well as the stupid floor mat getting caught under the clutch and not letting it completely disengage, needless to say I will be using them as a welcome mat from now on! I just wasnt sure if this tranny was sensitive, because it sure looks expensive to fix. My biggest problem is getting over the speed bumps in my neighborhood they are TALL and awkward and the car doesnt like to be in second at a snails pace, and it makes a fit when you shift to 1st without first putting it in second and going up from a stop. I think its mainly user error!

 

The ZF6 has all forward gears synchronized. You should be able to shift to 1st without coming to a complete stop. It is quite a low gear, so I don't go to 1st unless I am going pretty slow, but it should not grind.

This is not one of the old non synchroized 1st gear transmissions like our '60 Chevy was. That required a full stop.

 

I have today after owning my 1996 Corvette for over 18 years accumulated 46,XXX miles and have never changed the lubricant as per the 96's owners manual and the 1996 Corvette Service Manual. The 1996 Corvette Service Manual states that a transmission fluid in a manual does not require a lubricant change. The rear axle does not require a change of lubricant.
1996 Corvette Service Manual specifies in checking the lubricant level in the transmission torque the filler plug to 26 foot pounds and for checking the rear axle torque the filler plug 11 foot pounds.

Spark plugs as per the 1996 Corvette Service Manual has replace spark plugs at 100,000.

 

It was completely user error I suppose. I didn't have any issues today doing it. I planned on changing the fluid in the trans just as a precaution with GM synchromesh.

 

Changing fluids is insurance, as I see it, when properly done. I agree with many others who recommend changing ALL when newly purchased. Inspection of the removed fluid can give some insight into how the car was treated, especially true with high performance cars.

The ZF is also synchronized in reverse. Their weak point is the synchros (relatively soft material), so proper clutch operation is essential. Obviously, grinding gears is not good for any machinery, but it takes some learning/practice to shift smoothly. Increased shift effort is an indication that somethings needs attention, as the ZF shifts very effortlessly.

I use plenty of engine braking, i.e., downshifting, which normally does not include first gear, due to the low speeds, etc., however, I see no reason the design would have issues with that. SMOOTH is the key, as with any gear change or other driving activity. Note, many of the new cars employ rev-matching.