Tranny fluid leak, '97 GMC Sierra K1500

[swartzdesk]

I bought a used '97 GMC Sierra K1500 about a month ago (love this truck!), and almost immediately noticed what I thought was a very slow oil leak. A drop or two overnight. I'd dab it with my finger, check it, and it looked like motor oil (because, in hindsight, it was dirty from the ground and looked brown). I started checking the oil levels daily, and it was always fine. So I didn't think too much of it.

 

However, the leak seems to have picked up a little bit. Nothing too serious, but enough to notice. I noticed the drips were under the front passenger wheel well, so I put some cardboard down just to see if, in fact, it was motor oil.

 

It was not. See image:

 

 

I can't seem to find where the leak is coming from, but I see this under the hood right in front of the battery:

 

 

The trans fluid looks to be brand new, and the engine still shifts very well. Not wanting this to turn into a major issue, I'd like to get it addressed right away.

 

Have you guys had experience with a leak like this? If so, how much does it usually cost to get fixed?

 

When I bought the truck, they (obviously, they were sales people) said the seals were all checked. So take that with a grain of salt.

 

Lastly, anyone use and have success with any of those transmission sealers???

 

 

EDIT: It's an automatic transmission.

[txab]

Check the trans cooling lines for leaking. Check connections at radiator as well

[oldscsc]

x2 on what txab said. If you've got trans fluid under the hold, check the cooler lines that run to the radiator.

 

Stay away from the magic sealers at all costs. They will puff up all the seals in your trans and ruin the whole unit.

[swartzdesk]

Trans cooling lines = spot on. Replacing them. Thanks, guys.