Gear change with no Programing...what to expect?
Burning Brakes
Joined: Oct 1999
Posts: 835
Likes: 0
From: Fort Smith AR
Re: Gear change with no Programing...what to expect? (96WhiteLT4)
I have run my 97 without the HPPII and it hit the rev limiter if I got on it hard, and after a few miles the torque converter clutch would not shift out, (kind of like the fifth shift your trans seems to make.) (Barely push in on your brake while keeping the car at a steady speed in overdrive and it will shift out. This is what I am talking about.) In normal driving this is the only side affect.
Shawn
Shawn
Burning Brakes
Joined: Aug 2001
Posts: 1,206
Likes: 21
From: Roswell GA
Re: Gear change with no Programing...what to expect? (96WhiteLT4)
The main problem comes with the raise in shift points as they happen at a certain speed not rpm. With the higher gear the rpm needed to go 30 is higher so it shifts at higher rpm.
Experience has shown that 2.73 to 3.42 is too great a change to make with out hitting the rev limiter before it wants to shift.
You can get a GM dealer to re-program your PCM for 3.15's for only $65 and then put in 3.42's and they work just fine.
I and several others have 3.42 gears with stock 3.15 GM programming. Your shift points are about 10% higher RPM than stock. Funny / Neat thing about that is they end up about where the PowerLoader program set them to and you do not pay anything for the change.
I am putting in a ProTorque 2400 in the next couple of weeks and do not plan on programming for that either.
The PT2400 / 3.42 gear mod could be the best improvement in performance while staying with stock engine and stock programming available. IMHO.
Experience has shown that 2.73 to 3.42 is too great a change to make with out hitting the rev limiter before it wants to shift.
You can get a GM dealer to re-program your PCM for 3.15's for only $65 and then put in 3.42's and they work just fine.
I and several others have 3.42 gears with stock 3.15 GM programming. Your shift points are about 10% higher RPM than stock. Funny / Neat thing about that is they end up about where the PowerLoader program set them to and you do not pay anything for the change.
I am putting in a ProTorque 2400 in the next couple of weeks and do not plan on programming for that either.
The PT2400 / 3.42 gear mod could be the best improvement in performance while staying with stock engine and stock programming available. IMHO.
Thread Starter
Instructor
Joined: Aug 1999
Posts: 116
Likes: 11
From: Florida
Re: Gear change with no Programing...what to expect? (KingTut)
How does having the dealer flash me for a 3.15 differ from programming to a 3.15 with HPP3? The pblm I'm having is when crusing at say 65 my T/C will disingage/slip and after a couple times check eng. lite come on. This happens with or w/o programming. New trans and torque conv. Dealer says it's gears and or prog. After code is set(P1870) I loose performance. Thanks for you imput.
Burning Brakes
Joined: Aug 2001
Posts: 1,206
Likes: 21
From: Roswell GA
Re: Gear change with no Programing...what to expect? (96WhiteLT4)
I do not know for sure. There is a lot of interaction between the TC and transmission and what speed you are at and how far down the pedal is pushed, etc. It is quite complicated.
The change from 2.73 to 3.42 is 25%, it is only 10% from 3.15 to 3.42. I would think more stuff is closer to correct with the 3.15 programming.
What I do know for sure is the 3.15 to 3.42 guys have NOT had any such problems and $65 is pretty cheap to try as a solution.
The change from 2.73 to 3.42 is 25%, it is only 10% from 3.15 to 3.42. I would think more stuff is closer to correct with the 3.15 programming.
What I do know for sure is the 3.15 to 3.42 guys have NOT had any such problems and $65 is pretty cheap to try as a solution.
