98 GTP trans issues

[jeremylkelleysr]

Hey guys. I'm having a couple of issues with my tranny. I've been all over the web and think I have decided they are the result of different failures. The first problem is that it must climb extremely high in rpm before shifting. When I say extremely, I'm talking right about orange line. Think of it as holding the throttle to the floor until you get through the first two shifts and into third gear. The trans does NOT shift hard, its actually a good decent shift for 1-2 and 2-3. It does this whether you are shifting automatically or manually and does not change whether your foot is on the gas or off. Third gear is as far as it goes. I have no fourth gear...it doesn't even try. There is no slipping at all, it just doesn't even try to shift to fourth or lockup whatever the case may be. I take the interstate on my way to work and I run 70mph at about 3300 RPM and the car pulls just fine and I still maintain about 23-24 MPG if I stay out of that damn supercharger....which might I add, is NOT an easy task! as I said, I've been all over the web and cannot seem to find an answer to my high rev shifting with a decent shift. It seems everyone has a hard shift pointing to a PCS. While typing this, I am rethinking my lack of fourth gear/lockup. I've read a little about the problems with the splines wearing off and I don't believe that is the issue I am having as I believe that would cause a "neutral" or slipping situation when it shifts to fourth and mine doesn't even attempt to shift. I don't have the money to tear the trans apart and throw miscellaneous parts at it. Hoping to find a little more input through the gurus here who have helped me solve the impossible before! Lol

[Tech II]

If you do not have the car shifting into fourth gear, there should be a code set in the PCM.....at 65mph, the rpms should be under 2000 in fourth, with TCC lockup....

[jeremylkelleysr]

There is not. I have four codes but none of them refer to tranny to my knowledge. I have the MAF, #4 misfire, downstream O2, and I forget what the fourth one was but it fell under the same line as the other...all pretty well engine related

[tazpal15]

I have similar issues. My 00 GT will not go into overdrive. I put a new engine in and took it on a 2800 mile trip. The only thing is when warmed completely up. At idle when taking off. The tranny jerks into gear. Like idle in neutral pushing slightly on accelerator put in drive. The only codes I have is mass air flow and cam sensor. My research points to needing a hardened overdrive shaft.
How can stripped splines keep overdrive from engaging? There is no slipping or missed shifts. Just acts like a normal three speed auto.....