Transmission problem HELP

[4WD 4RNR]

I own a 06 4wd 4.0 and I thought I figured out the chugging sinsation between 40 and 45mph when I researched rumble strip tansmission, but Im starting to think its the torque converter. Reason being I was in the process of changing my engine oil yesterday I crawed under the truck while it was running( to let the oil warm up) I could hear a slight buzz coming from the bellhousing. Not sure but this sounds like my torque converter is going out, guessing this is why I can feel the chugging at 40 to 45 speeds. Unlocking and locking is what im think. Im hoping this is just because I havent serviced the tranny. It just hit 90k and I just bought ws fluid yesterday online. Any Ideas?

 

[sonerick]

I've heard that a chugging sensation between 40-45 mph is an indicator of a failed head gasket. How'd your oil look when you changed it?

FWIW, I didn't service the tranny at all until 120k, and never experienced anything weird.

 

[4WD 4RNR]

Oil was fine and the coolant level is good to. Truck runs great just need to know if it needs a new torque converter, or maybe just new fluid?

 

[sonerick]

Something like that is a little tough to diagnose over the internet. I've heard of people with the rumble strip issue solving it with some new fluid, and I've heard of some people going so far as to replace the torque converter. Sounds like you're on the right track though, start with a drain-and-fill of the fluid, and see if that makes any improvement.