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Grand Prix '98 loses transmission fluid while driving

A

alecswan

New member
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!
 


Fluid should be bright red to deep red, I would suggest changing the fluid and filter. While the pan is off, look for an excess of clutch material on the magnet and bottom of pan. Also might want to cut open the old filter and look for heavy deposits, metal shavings, anything that shouldn't belong. If you still have the factory ribbed pan gasket, check both sides for any cuts or damage to the rubber, that's usually where the leak is. Pay special attention to the bolt holes.
There are a number of things that can cause hard shifting, low fluid is one of them.
 
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 know about common, but if that's the only place the fluid is coming out of the car at, I have no idea where else it would go.
 
what you needed to a week ago is get the car on ramps and get under and look for the leak, we dont have eyes on it.

your gonna find a wet spot. leave the car running so it can actively leak with any luck while your under it.
 
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!
 


if you cant get under it hows the dye gonna work for ya?

jack and jack stands, a tall curb, any thing to get under it, and you cant fix it unless you can get under it most of the time.

you need to up your equipment game, or borrow some things asap.
 
If you add fluid..do you find a couple spots under the car?

If you answer yes...the weld on the dipstick tube from the bracket that holds it to the trans....it's doa. Get a fresh dipstick tube, you are one 10mm nut and a couple quarts of fluid away from your answer.
 
I had a transmission fluid leak from the transmission cooling lines near the front of the car. They rusted apart and leaked like crazy. The puddle was found toward the front of the car, not by the transmission. Put a big piece of cardboard under it overnight and see where it leaks.
 
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.
 
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