Noise from transmission when accelerating (2 Viewers)

[Stage10]

I've seen some posts in this regard but wanted to see if there is advice on my situation...noise when accelerating mostly in 4th...changed transmission fluid sounds a bit better but still noise. Any advice on cause? Would transfer case create what I'm hearing?
Thanks!

 

[bhsdriller]

Too vague could be anything. They are noisy to begin with

 

[peesalot]

Loose dline splines.

 

[B y r o n]

Older transmissions/transfer cases with straight cut gears make more noise than newer transmissions/transfer cases with helical cut gears. Other than running the highest weight gear oil there is nothing you can do to reduce the noise. While actually not totally true. If you install sound deadening material under or over the floor that will lessen the sound you are hearing.

 

[peesalot]

My orion with 90wt is quiet af.

 

[h82crash]

Not transmission gear noise if in 4th. Probably t-case. The aft driveline is getting more mechanical advantage in 4th. So the load on the t-case gears are highest.

 

[peesalot]

Is it loudest when in 4th coming to a stop or off ramp and you let off at say 45mph, it rattles loudest ???? if so its the drive line splines.

 

[Stage10]

Is it loudest when in 4th coming to a stop or off ramp and you let off at say 45mph, it rattles loudest ???? if so its the drive line splines.

Thanks !