Thread: Grand Prix '98 loses transmission fluid while driving

Hi there,

Several days ago I noticed that my transmission started shifting hard, so I added a quart of transmission fluid and it fixed it for about a day. Next day on the way from work it started shifting hard again. So, I added another quart of fluid. In the morning I checked under the car and only saw a couple of drops. So, I drove to work and it was shifting fine. Later in the evening after running some errands the problem returned. So, it looks like the fluid leaks when the car is being driven. I also noticed that when the problem occurs the color of transmission fluid is almost beige - not a lot of pink or rose in it.

The car has 250K miles on it but I haven't done any transmission maintenance on it for about 150K miles. I was thinking "well, the fluid is pink, so must be OK." To my defense I did perform good engine maintenance

Can hard shifting be caused by trans fluid or filter not being changed for a long time? Last week I had to replace my leaking heater hoses, so maybe now something is leaking in transmission system. Given all that, what steps would you recommend to troubleshoot and fix this?

Thanks!

Thanks for the advice, WarStryker13. I will work on changing trans next week, but is it common that a leaky pan gasket causes fluid loss only while driving?

I don't have a ramp handy to do that, so I decided to post here first. My next move after servicing trans was to add UV dye to the fluid to be able to trace the leak quicker. Thanks!

Thanks all for the suggestions. I did put a big piece of cardboard under the car over night and there were no drops. That's why I concluded that transmission fluid is being lost only during driving.
While I was waiting for response to my original post I added trans sealant and after a couple of days the problem seems to have gone away. I know most of you are cringing now, but at 250K miles I was looking for any way to add life to my trans
Anyway to summarize for others reviewing this threat:
* service trans
* consider getting a new dipstick tube
* check if trans cooling lines are leaking
* add UV dye and get black light to trace the leak
* "up your equipment game, or borrow some things asap"

Likely the cooler lines, they rust out like the brake lines do. A pan gasket will leak all the time since most of the fluid is in the pan while it's parked. Fluid is circulating while it's running which would lead me to suspect the cooler lines. As Scotty says, no way to know for sure until you get it in the air and get eyes on it.