2 days ago, I replaced my oil pan gasket, and it still seems to be leaking on the exact same spot. Behind the pan, where the oil pan “mates” with the transmission. I was told these engines have no rear main seal, so what’s next? I’m honestly at a loss, and if they do, could someone PLEASE tell me where they are located, and part number? Or where in the factory service manual is the procedure? Thank you!

This was before I replaced the oil pan gasket seal illustrating the leak point.

 

Umm, they DO have a rear main seal. Whoever told you that is stupid. Regardless, I wouldn't bother. I replaced mine a couple years ago and it leaks the exact same. Also did my pan gasket, front main, and oil pump. The truck just leaks. But I have 271k on it.

In my experience, once something leaks, there is no fixing it.

 

Put a large piece of clean cardboard inder the engine transmission. Are the drips brown or reddish. Brown is engine oil red is transmission fluid. Did you check the pan edges for straightness? Judging tby the picture, it's been whacked a few times and the edges might not be straight. I usually straighten oil pans before reinstallation. If you're not losing oil in a stream where you lose a quart every couple of days, just an occasional drip, I wouldn't worry about it. You can fix a leaky rear seal, but I'd only do it if the leak is really bad. The same with a front seat on the transmission. The actual seal replacement is easy. Getting to it, is a booger. You have to pull either the engine or transmission.

 

FEL-PRO BS40651 {#4483456} Info
Rear; Viton; Two-piece $16.27

FEL-PRO OS34409R {#53008610, 53008610AA} Info
PermaDry molded rubber Gasket. incl. $20.79
TIMKEN KWK99187 Kwik-Sleeve Info
4 speed trans.; Trans. code 46RH $18.72
SKF 18508 {Click Info Button for Alternate/OEM Part Numbers} Info
Front; Trans. code 46RH $10.33
These are for a 95, I don't know what year your truck is.

 

The leak might be from the back of the keg.