Looked at everything and can't spot anything.

Shift boot is on and tight - I took it off and looked at the rubber - no holes.

Seems like the engine is more pronounced in the cab now!?!

 

Check the drive line and U joints. Check all of your mounts. This may sound odd, but sometimes when you remove and replace them it seems to change something. I have the same problem. I replaced the transmission and I now have this harmonic drone @ 1600 rpm. Still chasing the cause.

 

No, not like that.

I can actually hear the engine in the cab.

Is there some sort of insulation on top of the bellhousing or something?

 

Bill? Where are you?

 

Check where the clutch master/linkage penetrates the firewall maybe? I have an auto, but I noticed a similar engine sound in the cab a few months back. Sounded almost like coming from the trans case shifter, turned out being the plug in the firewall for the clutch linkage.

Check around the trans case shifter. If you had the work done I wouldn't be surprised if the boot/mount wasn't but back on 100%. Is the noise at all times? In all gears?

 

I had something similar when my clutch was replaced. It was some kind of vibration transferred through into the cab. I pulled the console around the shift tower out and put it back in to check all the connections. Finally added a little insulation in there around the shifter and it ended up quieter than before. Never did track down the actual source.

 

I had the same problem. The trans shop didn't tighten the boot ring down all the way. It looked tight but wasn't. I pulled the boot aligned it and snugged it down properly. The sound disappeared and all was back to normal.
Hope this helps

 

I can't find anything...

 

After removing the center console the rubber boot around the shifter is visible. It has a metal ring around it. One time after hitting the ditch at a high rate of speed the engine noise in my truck increased noticeably. The dealer couldn't find anything under warranty so I had a looksee. The metal had become bent and wasn't sealing properly. I straightened it out and reinstalled it with silicone. Problem fixed. I bet they didn't bother taking the boot off when they changed the clutch and they bent it or jacked it up too high and bent the floor.

 

if you pulled your down pipe when swaping the cluch it might be touching the firewall. its a pretty close all arround with a 4" down pipe. atleast mine is.

 

Do what I did and try wrapping your entire shifter boot with a blanket or something and go for a ride. You won't believe the difference. Allot of sound makes it through the boot. Also when I changed out my clutch I noticed more sound radiating from the shifter and was thinking that the springs on my new clutch disc looked much more heaver duty so it may be better at conducting the engine noise than the old disc.

 

Some trucks use a foam donut right on top of the shift tower if that got left out it will do what you describe. It plugs the hole in the floor. Can't remember if dodge uses them or not but I think they do.Sometimes you have to bend up the rear part of the floor to get the shift tower to clear enough that you can remove the trans maybe it did not get bent back where it should be.

 

I've learned to live with it, even though its very annoying.

Thanks!