C3, Strange shifting.

[Larry Dana]

My '82 was not shifting properly, during normal acceleration, it would cycle through the gears way too quickly, (it would have gone through the gears and be in 4th gear and I would be barely going 25-30mph).

I took it in to my local chevy dealer and they said the transmission needed to be replaced, so, several hundred dollars later I had a new trany.

About three weeks later it started to do the same thing again, took it back and they said the trany they had put in was bad and needed to be replaced (no cost of course), so they did.

It has been almost three months now and guess what? it is starting to do it again! I have a hard time believing three bad transmissions.

Does anyone know if there are any external controls that determine what gear the transmission thinks it should be in? for example a vacuum line, or electrical signal from speed sensors, tach, computer or combination of above? (I would like to understand the workings a little more before I take it back in)

 

[jimq]

I think they used what they called a detent cable, it was a black plastic cable that went from your carb linkage by the accelerator cable, down to the transmission. I've seen lots of transmissions get replaced when that cable went bad.

I don't have an 82 and never worked on an 82 so I could be wrong. If it was my car I would take it to a tranny shop and ask them to look at/adjust that cable. If it gets worn it won't hold position, and it'll start shifting erratic again.

If you need a pic of the cable let me know and I'll see if I can find one, I have an old monte and they worked the same way.

 

[Pepe Le Pew]

Larry,
I had the same problem with my 1980. I posted the same problem back in May. member "Rpounds" gave me the following info and it worked perfect for me.
The shift points are regulated by the "TV" cable connected to the carburator at the throttle lever. Some people would call this the kick down cable which actually in this case is a misnomer. At any rate the proper method for adjusting it would be this:
Look for the bracket that mounts the cable to the intake mainfold. You will notice that there is a plastic piece that fits into a square hole on this bracket and the cable runs through this plastic housing.
On this plastic housing, usually located at the top, is a cad plated (silver color) metal tab. This tab is spring loaded, but by pushing in on the tab the spring can be overcome. Anyway push in on the tab and pull the cable toard the firewall (away from the carburetor).
While still holding in on the tab, move the throttle lever to the full throttle position. This will in turn pull the TV cable back through the plastic mount. Holding the throttle lever in the full open position, release the spring loaded tab. This will return the cable to the 'normal' setting.
Road test the car and observe the shift points. If you want it to shift sooner, push in on the metal tab and slide the cable (a small smount like mabe 1/8") toard the carburetor. If you want the tranny to shift later slide the cable toward the firewall. Be aware that if you move the cable toward the firewall beyond the 'normal' setting for a later shift, you will not be able to achieve full throttle on the carb. Also, you will run the risk of shifting to late during WOT operation.
This is applicable on late 70's and early 80's.

Hope this helps. It cured my problems.


Kenny