Why does it shift up?
Thread Starter
Instructor
Joined: Aug 2014
Posts: 108
Likes: 3
Why does it shift up?
I have a 4spd auto in my 86C4. I planned to use it for road racing and my first track day out I found that even if I held it in first gear it would automatically shift through the gears. I found a thread where teh poster suggested putting extra notches in the gear selector but I fail to see how that can help if I was holding it manually in place. When I let off teh gas when the RPMs dropped it fell back into first gear and it was like hitting the brakes. This seems to be a transmission computer programming issue. If it is not obvious this is my first GM auto. Our three Benzes all hold the gear that one selects. Granted the oldest is a 1998. Please help. I like the car and hate to toss it cause of this issue.
The only guy in town does Mopars exclusively and won't touch it.
The only guy in town does Mopars exclusively and won't touch it.
Race Director
Joined: Apr 2002
Posts: 10,036
Likes: 346
From: Anaheim CA
My '86 does not act that way. When I autocrossed it, I would shift into 2nd and leave it there. It would stay in 2nd (unless it's over-revved -- then the governor forces an upshift). Unlike some of the newer cars, if placed in 2nd it would start out in 1st and then shift into 2nd when I backed off on the throttle.
Melting Slicks
Joined: Nov 2013
Posts: 3,451
Likes: 336
From: Greater Cincinnati Area.
No.. The unit is hydraulic.
Check the description on this shift kit:
There is some (very limited) hydraulic protection in many of the early units. (Many of the later ones have this protection in the programming.) and if you want to defeat that, you can.. But the description means exactly what it says, so be careful.
If you're autocrossing and really wringing this thing out, you might want to couple this with an upgraded shifter.
Good luck!!
Check the description on this shift kit:
TRANSGO PART: 700-2&3
FITS: THM 700R4 81-Up
FEATURES: Optional Stick Shift; or Gear Command with automatic upshifts; Holds 1st, 2nd and 3rd at any rpm. Backshifts to 3rd, 2nd and 1st at any rpm; Competition, Off road And Pro-street;
http://www.transgo.com/products.php?...product_id=169
FITS: THM 700R4 81-Up
FEATURES: Optional Stick Shift; or Gear Command with automatic upshifts; Holds 1st, 2nd and 3rd at any rpm. Backshifts to 3rd, 2nd and 1st at any rpm; Competition, Off road And Pro-street;
http://www.transgo.com/products.php?...product_id=169
If you're autocrossing and really wringing this thing out, you might want to couple this with an upgraded shifter.
Good luck!!
Melting Slicks
Joined: Nov 2013
Posts: 3,451
Likes: 336
From: Greater Cincinnati Area.
PS and related: Megashifter install thread with pics.
https://www.corvetteforum.com/forums...ll-w-pics.html
https://www.corvetteforum.com/forums...ll-w-pics.html
