I change the transmission filter and fluid in my '07 every 25,000 miles or so, and haven't had a single problem in 150,000 miles- I bought the car used with 40,000 miles in '09. I always re-used the pan gasket and torqued the pan gasket bolts to about 110 inch pounds and it never leaked a drop until recently.
I thought I would be smart and replace the gasket as my car approached 200,000 miles. It didn't leak, but I figuredthat it might start. BIG mistake! The replacement GM gasket began to leak as I was filling the transmission. Tightening the pan bolts did nothing to stop the leak, so I bought another gasket and pan and replaced both. Once again there was a significant leak with both parts being new. WTF?? The original gasket was gone and in the landfill by then, or I would have re-installed it.
Next I tried Permatex black gasket maker specific for crankcase and transmission pans. The resulting leak was the worst of all! So I ordered another pan and gasket from Rock Auto, since the previous suppliers, including NAPA, had sold me junk. New junk!
The Rock Auto pan was OEM quality, included a magnet, and NOT powder coated. The gasket was in an A/C Delco wrapper and looked good, I examined every inch of the mating area. I had also bought new 6 X 20mm bolts previously. I carefully installed both parts and torqued to 110 inch pounds.
So far, so good, no leaks. I was amazed that it took so many attempts to do a simple job with the low quality parts that you get these days. I am not promoting Rock, but I have never had to return a part that I bought from them.
My advice to everyone who reads this- DO NOT replace the transmission pan gasket until it starts to leak, if ever. Lucky for me I have a QuikJack lift and could raise the car easily, this would have been pure hell using a floor jack and jackstands.

 

The pan bolts torque specification is 89 inch pounds. Perhaps the 110 inch pound , distorted the flimsy pans.

 

I torqued the previous OEM gasket to the same spec for 15 years with no problem, and the new pan was of the same gauge. I'm under the assumption that the gaskets are not made to the same quality, with the exception of the Rock Auto gasket. I noticed that the seals at the bolt hole openings were thicker than previous versions, much like the OEM gasket. Every gasket had 4 ridges of rubber that acted as a seal when compressed, but the bolt hole seals weren't thick. Remember, the original gasket was meant to be re-used.
21 inch pounds wouldn't make a difference under normal circumstances. The bolt hole seals would prevent over-torqueing, much like a solid washer.

 

I found it very easy to bend the pan with the nuts. That is where mine leaked. Solution was to buy a new pan with a drain in.

 

I'm a Rock Auto fan but they are a purveyor, not a manufacturer. I have no idea if they are more selective, but they offer at least some of the same junk that their competitors do.

I appreciate your post as a cautionary tale. For those who think they can just skip the torque wrench, stripped threads ain't the only risk. Also, every procedure carries at least a slight risk, including unnecessary ones. Unless yer pulling a trailer up mountains or something, it's tough to justify transmission fluid and filter every 25K on these cars. The automatic is overkill and usually loafing, and GM (for what it's worth) GM says it's lubed for life.

This is the best answer.

 

The original gasket has a metal center and thicker rubber. The replacement is a thin bit of rubber.

 

I did specify the flimsy pans are easy to distort especially if the pan gasket is also thin with no metal pieces to stop the bolts from crushing the pan and gasket.
it doesn’t matter who makes the parts , RA is a vendor, not a manufacturer, just like Amazon, they provide good prices, it’s up to the consumer to determine their purchase decisions based on price or quality.

 

Problem found! The left axle seal was leaking, allowing transmission fluid to seep down to the pan and give the illusion that that pan was at fault. I replaced the seal (not easy) and that solved the problem. The seal began to leak when I did a transmission service, a coincidence.

 

Thanks for your follow up! Glad you got it fixed!

 

im having this same problem brought the new gasket from O'Reilly should I tried ordering a new gasket from the place you mentioned hmmm or could it be the axel as u mentioned