You didn't say what vehicle, but for nearly any automatic transmission there are only two leak points inside the bellhousing area.
One is the front pump seal that seals the torque converter drive neck.
The other is the front pump-to-case gasket and o-ring.

The trans must be pulled off the engine to service either of these areas

 

1985 Camaro 87 350 71 th350

 

The converter hub can be cracked and will cause a heavy leak of oil

 

I was attempting to make sense of your question. It appears that it is a Turbo hydramatic 350. On 350 transmissions remember that evertime the front clutches are activated, they are pushing on the front pump housing. It is very important on a 350 trans that the front seal is glued in, not just pressed in. Also that none of the pump bolts are not stripped out. A heli coil can easily repair any stripped holes, This is actually quite common on 350's, the torque on these bolts is only 15-18 FT Lbs. This is not a lot of torque, I find these stripped all the time because of over torque! It is also important that the front pump bolts have new correct sealing washers. These washers should be replaced on every rebuild. Hope this helps. Good luck on your project.

 

How long will it take to pull trans and check everything you mentioned mechanically I'm a 5 and a half on the ten scale

 

Remove is about 15 minutes. Not sure how long it will take you.

 

Trans removal time depends on your skill level, tools and if you have a way to get the vehicle up in the air to physically work on it. Driveshaft removal, shift linkage removal, cooler lines, modulator vacuum line, Unbolt the torque converter from the flexplate, push the converter back into the trans, Then a proper trans jack, crossmember removal and six trans bell housing to engine bolts. I have a lift so it takes me about 35 minutes taking my time. Transmissions are heavy so safety counts. Trucks take longer because of the transfer case.

Something I forgot in my previous reply is also to check the front pump gasket and also the outer seal. I always replace with a new gasket and new seal. it is a square cut seal. I always use Vasailine on the seal and a small amount on the circumference of the pump when installing. Never use the pump bolts to pull the pump into place, You will most likely strip out the threads on one or more bolts. These are small 5/16 bolts and will easily pull the threads out of the case!

I have two 5/16 bolts that are about 3 inches long with the head cut off and A slot cut in the cut off end. The slot is for a screwdriver. I use these as alignment pins when putting the front pump in place. A rubber hammer or plastic dead blow hammer with small taps usually seats the pump in the case. I then remove the homemade alignment pins and then install the bolts. *Please don't use a metal hammer to tap the pump into place. You will crack or distort the pump.

Hope this helps.