If spedo dies, 2nd and 3rd are locked out

[Familiar_Enemy]

Oh boy where to begin..

95 Trans Am convertible. Automatic to manual swap which I didn't do and don't have any information on. 17 inch tires... stock is 16 right?

The spedo is sort of... droopy? It will go up with a hard acceleration but isn't accurate and soon falls all the way to zero no matter what speed the car is traveling at. In order to shift into second, a hard acceleration is required and so on for third as well. The gear is psychically locked out as I can't get the shifter into the the spot it needs to be as opposed to feeling like the gear just isn't there.

First and fourth are pretty reliable though, I can always get into either and fifth and sixth don't seem too affected.

Also just to throw a wrench in the mix, this problem came up for about a month last summer then just randomly went away untill now. The engine is suffering some how as well because of this problem. The engine will die sometimes as soon as I shift into neutral to coast before a red light. Under load and idling to warm up for 20 minutes there are no problems though.

Any thoughts or ideas welcome. Thanks!

Edit: Also I took it to get the clutch and throw out done soon I got it about a year ago and throw out is making noise again already. Reverse worked fine when I took it to the shop but ever since it takes two hands to muscle it in.

[BLK95TA]

2nd and 3rd being locked out under light acceleration is normal. thats the cags(computer aided gear selection) system aka skip shift. it was to keep from getting the gas guzzler tax. IIRC there is normally a light on the dash that says skip shift when this occurs. since your car was originally an auto it doesnt have it. i believe this can be bypassed with a plug in module.

as for the speedometer i dont know why it would just stop working.

[steveo]

your ECM has decelleration modes that are supposed to correct idle when rolling to a stop, so if your vehicle speed sensor is malfunctioning, that might cause it to stall. it'll also affect when the 'skip shift' function happens. it's all related.

go to some electronics store, get a 2.2k ohm resistor, jack up your car, get to the transmission

you'll see a plug close to the center of the transmission (away from the other plugs), that's the skip shift plug. unplug it, stick the resistor in the plug, tape it up, and shove it somewhere, that solves that problem. or, forget the resistor and just unplug it, but it'll set a check engine light.. better than nothing though

there's a big cylinder with a plug on it, that's the reverse lockout. below that is the speed sensor. take the plug off, make sure the contacts are clean, and stick it back on. that might solve your problems. it's likely that when they did the transmission swap, they left it loose

[Familiar_Enemy]

Hey there, thanks a ton for all the info. I wont be able to jack it up and check it out till I can find a proper garage to pull it in to. Just got 4 inches of snow and I dont feel like getting snow all down my back!

I gotta ask whats the resister do? Do i need that because the car used to be an automatic? What does the skip shift have to do with locking out gears? Sorry, I'm pretty new to newer cars. My 84 TA never needed this much love.

[BLK95TA]

the resister bypasses the controller that makes the skip shift work IIRC.


skip shift was a way to force a 1-4 shift at light throttle to get better gas mileage so the cars wouldn't be hit with the gas guzzler tax. all 93-02 fbody 6 speeds had it, as well as all 89?-current 6 speed corvettes.

[Familiar_Enemy]

Wow, thats interesting. Seems almost a waste of gas just to rev first high enough to run in fourth. Anyways, I shot a quick vid from my phone yesterday on my way
home of the problem. Since snow is predicted all this week I'm pretty screwed but if i dont do it, I'll have a heck of a time if i get stuck!

I recommed turning your speakers down before playing the video.... Sorry
youtube video

And yes the brake light is on in the video, and yes the passenger seat is torn. You cant see it but the abs light is probly on too.... And dont worry about the random wire in the shift boot. Ugh

[steveo]

just unplugging the connector works too in the short term, the resistor is just to shut up the computer... which will set an error code, because technically, skip shift is an 'emissions control device'

the skip shift also relies on vehicle speed, so if your vehicle speed sensor is sketchy, it'll try to force you to skip shift when it's innapropriate. get rid of that thing while you're trying to figure the speed issue out.