Transmisssion Leaking looking for some guidance and opinions

[bornaRAMblinMAN]

I had a leaking pan, it got too low, overheated and burned the fluid, and now it leaks from the bell housing. I am considering taking it out myself and getting a rebuilt transmission for $950. If I have the shop do it it's $3000.

The truck only has 120,000. It runs pretty good, there was a o2 sensor code that went away and the voltage looked good when I hooked up my elm327, so I am thinking the cat was either dirty from old gas etc or there could be a leaking head gasket.

My current plan is to test the compression, then if it's good, I can change the cat if the code comes back. Then I am going to check the frame thoroughly and proceed with the the transmission replacement if everything looks good.

I already replaced the exhaust flange bolts with new ones and used anti seize. I am not a professional by any means and if I do decide to remove the transmission myself it will be the biggest project I have done so I am trying to make sure I am doing everything right and not overlooking anything so any input is appreciated.

 

[fastf]

Ok if the engine is running fine it ain't no head gasket that would dirty up a cat i can tell you from experience I had to replace a cat on my wifes car because of a misfire on one of the coil packs.It looked like someone took a bite inside of it.First I would replace the transmission and fix the other stuff afterwards or do it while you are fooling with the transmission.

 

[bornaRAMblinMAN]

OK Good point, I just don't want to throw good money after bad so I want to be sure it has good compression before I invest the time and money in the transmission.