Engine/Transmission (1998.5 - 2002) Weird problem after start up!

[Mbranson]

I hope someone can help me,the last two times I started my truck a few seconds after it starts I hear and feel a slight bang in the floor board then it does it no more. It runs fine, shifts fine, no vibrations, it runs no different than before the problem started,any help would be appreciated. 01. 5 quad cab 4x4 47re auto 2500 5. 9 74. 000 milesOo.

 

[AEdelheit]

I know on my 3rd gens when the ac compressor clutch engages it could make a pretty loud clunk that I could feel, dealer swore it was normal , if you ac or defrost is on try turning it off and see if it still does it, kinda doubt its the problem but worth a shot!