3rd to 4th gear problem
Thread Starter
On The Tree
Joined: Jan 2004
Posts: 166
Likes: 2
From: Bahrain
3rd to 4th gear problem hi guys, i have a problem with my 2000 camaro.
my car comes whith an original ratio of 2.73 and i have changed it into a 3.42 ratio. the problem is when i i give it full throtle it dosent shift from 3rd to 4th gear. but when i drive it normally it shifts normally too.
Note: when i changed the ratio i didnt tune my PCM.
Please help
my car comes whith an original ratio of 2.73 and i have changed it into a 3.42 ratio. the problem is when i i give it full throtle it dosent shift from 3rd to 4th gear. but when i drive it normally it shifts normally too.
Note: when i changed the ratio i didnt tune my PCM.
Please help
Last edited by Public Enemy; Sep 24, 2005 at 06:15 PM.
Thread Starter
On The Tree
Joined: Jan 2004
Posts: 166
Likes: 2
From: Bahrain
Originally Posted by LoPeY
It would make sense to me that your car wouldn't switch from 3rd to 4th when you go WOT, unless you're at redline.
By changing your gear ratios without getting the new ratio put into the pcm the computer doesn't know how fast you are really going (assuming so since you didn't mention anything about a reluctor wheel to do the conversion for the pcm.)
Because of this, when you are at WOT the computer won't shift because it doesn't think you are hitting the wheel speed to call for a shift. This isn't as noticable when you aren't at wot because the shift events are different.
The problem should go away once you get the new ratio input into the computer.
Because of this, when you are at WOT the computer won't shift because it doesn't think you are hitting the wheel speed to call for a shift. This isn't as noticable when you aren't at wot because the shift events are different.
The problem should go away once you get the new ratio input into the computer.
sounds like a transmission problem to me. i went 273 - 373 without computer tuning and the car shifts exactly the same way it did before. the gear change has nothing to do with the shift events.
I do not have an 4l60 automatic, so I am not sure on this, but I do know for a fact that the 700r4 4 speed auto (non computer 4l60) will not shift into fourth at wide open throttle, also it will downshift into third no matter how fast you are going at WOT. I have had several transmissions modified to eliminate this issue. The reasons I have been told this happens is that a WOT shift to fourth is harsh on the clutch packs, and the more believable reason I have heard is that , like in Public enemy's case with 2.73's at the top of third at full throttle you are going shall we say "a little fast" and GM did this so you can't hold it wide in fourth and go to ludicrous speed.
Actually, since it was brought up, anyone get a 3-4 shift at full throttle on the 4l60? Now I am curious.
Actually, since it was brought up, anyone get a 3-4 shift at full throttle on the 4l60? Now I am curious.
