Transmission moaning/groaning

dodge
ram
1500

#1

I have a 2004 Dodge Ram 1500, 5 speed manual with 110k miles. This past winter, the truck has started to whine when it’s in reverse. The strange thing is that it also whines when it’s in neutral and simply rolling backwards. It’s intermittant, which is why I’ve been hesitant to take it to a shop to have them waste a bunch of time with it and say they can’t reproduce it.



Things that make it more likely to occur – the truck being cold (IE: shortly after a start), air temperature being cold, when it’s in 4WD. When I brake, it stops immediately. If I have the clutch on the floor or the transmission in neutral, it will keep doing it, as long as it’s rolling backwards.



This never happens in any forward gear, and it’s been happening intermittently for a few months now. I had the transmission fluid changed this past fall, sometime before I noticed it started happening.



Thoughts/ideas?


#2

Is it possible the wrong type of trans fluid was put in when the fluid was changed? It sounds like bearing noise when certain shafts are moving. I’d change the fluid again and be sure it is the correct fluid. Perhaps even consider buying the fluid from a Dodge dealer.


#3

Maybe it’s not the transmission at all and this problem is due to a whining belt tensioner or idler pulley bearing.
That would be my suspect rather than the transmission; especially if the truck has say a 100k or way more than that miles on it.

You might remove the accesory belt and carefully examine those pulley bearings. They should rotate without any free play and should be silky smooth. Place a finger tip on the mounting bolt of each and spin the pulley by hand. If you feel any roughness (even a very subtle tick) the bearing is failing.


#4

I’m also going to suggest to look beyond the transmission - and I’ll go out on a limb - partly on the basis of this: “When I brake, it stops immediately.” Often when brake pads are getting close to the end the wear indicators can produce noise intermittently. You could have a wear indicator on a pad with just enough of a tweak in it to set it to vibrating only in reverse and not in forward motion. (It would have to be bent slightly toward the front of the vehicle leaving a front corner sticking toward the rotor).

In addition, when the truck is cold it has to have been sitting for a while. Rust builds up really quickly on rotors - so the surface rust on the rotor makes the contact more likely until the surface rust is gone.

I’m not sure how outlandish that sounds - but its pretty easy to check.