Strange knocking noise A4LD transmission

[FoosballPaul]

Hello all,
94 Ranger, 4.0 4X4, A4LD transmission.
Just replaced engine. After engine installation complete engine started right up and runs smoothly. Problem: Very strange intermittent banging noise that seems to come from front of transmission. When in park engine can be revved at slow but constant speed up to 4K but if I accelerate I hear a loud clanking/banging noise. When I put it in drive the noise gets worse. Noise sounds like hollow metal banging on metal and seems to originate from front of transmission where it mounts to engine block. Not a steady rhythmic noise but sporadic noise. I have checked all the exhaust system and noise doesn't seem to come from exhaust. I am at wits end on this one.

 

[enjr44]

Well, my first guess is that you didn't get the torque converter installed correctly. Either it was not installed all the way into the transmission before bolting the engine to the trans (which will break the front pump when you pull the engine/trans together). Or, the bolts to the flex plate are loose.

 

[twb4525]

Well, my first guess is that you didn't get the torque converter installed correctly. Either it was not installed all the way into the transmission before bolting the engine to the trans (which will break the front pump when you pull the engine/trans together). Or, the bolts to the flex plate are loose.

Yep, x2.

 

[FoosballPaul]

Thanks for the response. It is always helpful to have an extra set of eyes and ears when trying to diagnose any problem so I asked my friend to lend me a hand. Turns out that the engine is backfiring through the exhaust which causes the sound to seem to resonate from the transmission housing. This is a very inconsistent backfire. The engine runs as smooth as silk when gradually accelerating from idle up to 4K. When put in gear or fast acceleration there is a very sporadic backfire through the exhaust. Sounds like the exhaust is about to be blown apart. Now I have to determine what is causing this problem.