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Discussion Starter #1
I'm currently having problems in my Automatic 1996 Corvette. Recently, my linkage shifter cable broke. I tore the console apart, pulled the whole shifter out, partly because that was the first time I've replaced one on a C4. Always, while I was underneath the car I decided to pull the exhaust off and install the new shorty headers that I had bought awhile back. After I got done installing the headers, I put the cats back on, and started her up. She started right up. Then I went for a test drive (I left everything past the of the cats off. After driving for a little bit I noticed the transmission started acting funky. Well I tried to go into park and it wouldn't so I assumed it was the linkage was off.

I bring it back home and the retainer clip had pop'd off the bracket so the cable wasn't stable. I made a new clip and fixed the linkage. Still the same problem.

If I have the transmission in OD, it will shift from first then to second. After it tries to go into D or OD. it just completely rev's like it is in neutral. My first though was "Oh no I lost another transmission stupid 4L60E" But this was different. I've have my tranny rebuilt 3 times (the first 2 times were by people who didn't know what they were doing) and the last time was down by a local guy here who has been building race tranny's for 30 years.

It is something electronical because if I give it WOT it shifts 1st/2nd then if I let off around 45-50mph it drops into 4th and it runs fine. After it does that I can literally give it gas up to highway speeds and not slip. Also If I give it light gas and manually pop it from 2nd to 3rd and 3rd to 4th it shifts. The transmissions stays at 170-190degrees. Last time I lost my 3/4 clutches it was heating up to like 240-250.

I pulled out my 4L60E book and read that it could possibly be the VSS (Speed Sensor), so I bought one of those and slapped it in the ext housing. Rehooked up the battery and it still doing the same thing.

The only codes I get when I paperclip it is H71 and H72. One of those is from my aftermarket radio.

I know it isn't a shift Solenoid because I have first which is A and B ON.

So I guess my question is, did I burn a wire or something with the open exhaust or knock something loose pulling the headers out? Any Ideas?

Thanks
 

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Wow thats a good one. I am just throwing some thoughts out here. First I am wondering what caused the shifter cable to break? Old age or a tight shifter. Second would be the valve body. It seems like maybe its not getting the right pressure to the right places? I had a problem like this as well, Mine would not go in to 4th. I changed a spring in the valve body and it solved the problem. How about O2 sensors? Dont know if they have anything to do with it or not. Sorry, I wish I could be more help. At least this will bump the thread to the top again :huh:
 

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Discussion Starter #4
Old age broke the shifter. It's got stock shifter in it. I've got 130k, I got her at 50k as far as I know no one has ever replaced the shfiter cable, so it was due.

I replaced my O2 sensors about a month before I put the headers in.

I know, I at a loss. Weirdest thing I've seen. Would the valuebody springs effect *just* the automatic shifting? Like I said what is weird if I manually pop it up to 3/4 it shifts, as long as i'm above like 1800rpm (could that be a converter lockup thing??) (Stock Converter in it). Or If I'm stopped and it's in OD and I WOT it and let off it'll lock into 4th. I dunno. :thud:

In a perfect world I could just floor it at every light and there wouldn't be a problem :laughing:
 

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Hummm Good point if it was the spring thing it would never go in that gear. Seems like there must be some sensor in the path some place that is telling the trans somthing diffrent when its at WOT. Got me. Anyone got any ideas??? Anyone...... Hello... Where did they all go? All you have to do to clear a room full of vette fans is say 4L60E... :D Good luck, I wish I was more of a help.
 

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This EXACT thing just happened to me today... So I did a google search and found this thread. Was really hoping for an answer! :laughing:

Let me know if you find out what this is!
 

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Discussion Starter #7
Wow I'm already on google. I feel special! :partyon: :laughing:

Is yours a 1996 also?

I plan on dropping the pan and looking for shavings and change the filter and fluid soon to see if that gives me any luck. Maybe it'll be that simple. I Hope so. :huh:

I mean maybe it is *possible* that is is the 3/4 clutch pack it is time for my yearly 4l60 rebuild :rolleyes: but when I do force it to shift it is "sticky" not slipping. If I leave it in gear and let it shift itself it does "catch" but it still feels like it is in 2nd gear just slippy.
 

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I tried to post this once already but I guess it didn't submit.

Ok, Last night I dropped the pan and checked, no shavings. I went ahead and replaced the filter and put new fluid in. Started her back up, still same problem. I decided to drive around and play with it alittle bit (since I know the transmission is ok, since there were no shavings).

The problem is actually a little bit different then I thought.

Lever in First
First Gear works w/o any issues.

Lever in Second
Starts out in First, then when I let off shifts to Second light throttle or WOT, no problems

Lever in Drive
Starts out in First, if I give it WOT till 5000rpm+ then let off it drops into 3rd w/o any problems.

If I lightly give it gas (50% or less), it tries to shift into 2nd, but instead of going into 2nd it engages the overrun clutch and stays in 1st. If I then give it gas it revs up to where it should be in first, then I let off it drops back to 1500rpm (where my stock converter stall is). Weird. :bang

Lever in OD - Same as Drive but it drops into 4th on WOT. if I give it 25%+ throttle while in 4th it drops into 3rd and runs fine till i let off then it shifts back to 4th.

What I forgot to try (I didn't want to drive it very long) if i WOT and let it shift from 1st would it go to second (I'll try that when I get home for lunch)


It's definally something electronical, I should of changed the shift solenoids when I was in the pan, but since I do have automatic 1st which is ON ON and 3rd which is OFF OFF and forth which is ON OFF, I can *maybe* safely assume that 2nd which is OFF ON should work.

I dunno :bang :bang :bang
 

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Bought a 1996 C4 in an auction today, Put in new battery and Varooooom from the first key twist, Shifted the Auto into ((D)) and it hooked up fine, dropped from 900rpm to 700rpm. Let off the break and away I went smooth as silk! Got to the gate and left the lot taking it easy for the first time out and still ok, got to about 30mph 1500rpm and it felt disconnected! Motor revved but speed didn't follow rpm. This was at partial throttle. Punched the go peddle and it down shifted and went like a bat on fire! Upshifted and caught this time! Did this at ever stop light 7 miles home. Don't want to drive it till I am sure driving it wont hurt it! Anything work off a vacuum and when you floor it the vacuum drops and the trans works? Doesn't like being treated like a lady, but when you spank her she runs like a (you get the idea)! What's wrong? I know NOTHING about automatics. old1 Texas
 
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