Transmission problems

[Mattyg717]

Hey guys so I recently bought a 99 GTP got it for a killer deal to say the least....im totally pumped on this car sept for a few minor problems im having..the sport shift button does not work and the tranny starts slipping when im on the free way in a high gear and also the display on the dash isnt workin properly in the sun U can see that it's on but there no illumination to it how can I fix these problems without havkng to spend a arm and a leg please help thanks

[BillBoost37]

Welcome...

Trans.. likely you need to swap it out or rebuild it.

The display, if it's only an issue in the sun, that is normal. It's tough to see.

[wmorrison65]

the tranny starts slipping when im on the free way in a high gear

I'm new to the Grand Prix world, but I've had transmission problems with Chrysler/Dodge that turned out to be a $25 part, a transmission speed sensor (input or output, I can't remember now.)

Symptoms: Starts normally, start driving, going down the road the transmission will slip, then recover. (Basically, if the sensor can't detect shaft speed it throws the transmission into neutral.) After a few more times of this, the transmission goes to "limp mode" where it won't go into higher gears, but otherwise operates fine.

I don't know if this is applicable to Pontiacs, but just throwing it out there as an idea, because it's been a cheap fix for me 3 or 4 times on different Chrysler/Dodge vehicles.

[bobc455]

When you say "the tranny starts slipping", do you mean that the torque converter is unlocking?

[Mattyg717]

When im cruzin down the freeway you'll feel it kinda jolt see the Rpms go up a lil but then go back to normal then when U get on the gas you'll feel it slip then kick down and take off ...also my sport shift button does nothing could this be part of the problem and as for my in dash display I was told the bulb inside the u it self can go out and cause U not to be able to see it it doesn't light up at all...

[Scottydoggs]

sounds like a the 4 th gear hub is worn out. the replacement hardened 4 th is like 40 bucks now.

put the car in 3 rd gear on the highway see if it still slips, if not thats the 4 th hub wearing out.

edit: the perf shift button could be a rubbed through wire by the pcm. you should be able to feel a small difference on vs off.

[idrivejunk]

On the dash display... since you're not yet familiar with all the acronyms, lol... and a couple of these guys helping drive Buicks...

The display on top of the radio and A/C control stack in the center of the dash facing the driver is called the DIC (Driver Information Center) on a 99 GTP. The one on top of the dash facing the sky is called the HUD (Head-Up Display) and it projects onto the windshield, if so equipped. The DIC is an LCD (Liquid Crystal Display) with a dark lens over it. When that display is dim, the bulbs that backlight the dark lens so you can see the LCD have gone out. Theres 3 or 4 maybe and they are funny looking but parts stores have them. Take the dash bezel off and the DIC can be easily popped out for bulb replacement, then you'll be able to see the DIC at all times. Makes the car feel like less of a POS if that works right.

Carry on with the other issues

[BillBoost37]

In 99, won't he have a lego block DIC? Also known as the most worthless boost gauge ever put in a car.

Don't be talking about the Buick...til you know what it's info center looks like bishhhhhhes

[Hot wheels]

My 98 gtp is in the shop as we speak and it was doing the same thing as your transmission. TCC was messed up so with the miles I had on the tranny I had the shop just replace it with a low milage one.

[Mattyg717]

@idrivejunk thanks for that info think I have that problem solved now as for the tranny still workin that problem out its going to the shop next week and they can deal with the problem hopefully I don't have to put a new tranny in cause it's only 4th gear when im cruzin that it starts to slip and so weird **** so we'll see what they have to say when I take it in what do U guys know about the Grand Prix gxp I saw one of those the other day at the stereo shop and that thing looked bad ass and sounded even badder kinda want one now lol