98 GTP Transmission Problem ( Random Humming and Hard Shifting)

[pmk138]

Hello,

Just wondering if someone can point me in the right direction. I have a 1998 Grand Prix GTP. I bought it with 65,000 miles and now there is 118,000 miles on it. I occasionally run into a problem were my transmission starts to whine and shifts hard with a light bang. I originally ran into this problem when I was traveling some steep mountains in the summer. It would start up the mountain fine, but then the whining noise would start as I was going up the mountain and the noise would remain going down the mountain. It would also remain while driving on level ground. The noise wouldn't go away till the next day after the car was parked in the garage. Along with the whining there is a noticeable banging with the transmission shifting gears. I notice the bang even when shifting from the Over drive to 3rd gear. I believe this is a transmission problem. Please let me know if you have any idea how to fix this. Do I need a special code reader to check for transmission codes?

Thanks,

Paul

[Fivefingerdeathpunch]

You will need more than just a generic code reader to get transmission DTC"s, some even reset after the ignition is turned off so you'd have to scan it after the problem happened.

How is the fluid condition, ever been changed?

Almost seems like it's getting so hot and once it fully cools down the noise goes away but that's just a guess.

[pmk138]

That is what I am kind of thinking. But if that is the problem, I wonder what is causing it. I would hope a simple fluid change and filter change would solve the problem. I would bet the fluid hasn't been changed. I myself have never changed it. When I changed the super charger fluid, it was really dark and had a terrible odor and that was done soon after I got it. What type of fluid do you recommend? I didn't look at the manual yet to see what it calls for, but I know sometimes newer and better products come out after the manual is printed.

[Scottydoggs]

id stick to dex 3 what it says on the dip stick to use. you can use dex 6 but its thinner and id not use it in a used tranny.

[pmk138]

I changed my radiator fluid to Preston. I assume that wouldn't be causing this problem.

[Scottydoggs]

nope.

[pmk138]

Any recommendation on the filter and gasket type?

[Scottydoggs]

get yourself 2 cans of brake cleaner to clean the pan, and the stock gasket, re use the gasket. filter is a filter, really dont matter, what ever they got at the local parts store is fine.

pan drop will take you 8 qts of fluid too.

drive the car till it acts up, then drive to a autozone but dont turn the car off, have them scan it running, there could be a pending code there that will go away once you turn the key off.

if you find you have a max adapt shift code install a shift kit when the pan is dropped. transgo is about 35 bucks shipped off ebay. theres how to's here with pics, its rather easy.

[pmk138]

Hey Thanks for the help.

[pmk138]

I am thinking on buying a CRP123 scanner. Do you think this will he narrow down the problem. I should have no problem getting this problem to occur again. I just need to drive up a steep mountain.

[Scottydoggs]

a cheap 20 dollar code scanner will also read the tranny codes. with the price of that scanner listed its best to make damn sure it will read all the things listed on your car. abs codes dont always scan like they should.

[pmk138]

Well the scanner I currently have is a MS509 OBD2/EOBD scanner I bought off of ebay. It doesn't specifically say it can scan a transmission. I did get a check engine like on my dodge ram and I was able to scan it with my scanner and it ended up being a "Transmission Output Shaft Speed Sensor". I was thinking there is a scanner that can is more powerful to scan a transmission. Maybe I am wrong.

[Scottydoggs]

engine and tranny are normal obd codes, nothing fancy needed to read it. try the scanner you have as long as you own it already.

just googled it, thats a nice scanner for its price, says it shows live data. plug it in see whats up.

[pmk138]

Alright. thanks again.