I have a 1999 Dodge Dakota 2WD V6 Ext Cab Standard trans.
I hear a sound coming from the rear end of the vehicle in every gear as I accelerate. Once you let of the gas the noise goes away. Touching the gas brings the noise back.
Sounded like it might have been the muffler slightly rubbing on the driveshaft.
Since I had just replaced the muffler a week or so ago I thought that might have been it. Tightened all the muffler/exhaust clamps, etc and the noise is still there.
If you think it's the differential, is it a good idea to try replacing the bearing and seals?

 

I would check the ujoint, rear brakes, change the diff fluid and while its opened up make sure there arent any big metal shavings. If the pinion bearing goes out it will start eating at the R & P. If none of that is it, I would start to check out the transmission, mainly the output shaft bearing and seals.

 

yeah, I second that, look at the ujoints.....I haven't even looked up under my truck yet, LOL.....is there a carrier bearing on the driveshaft on these dakotas?

 

no carrier bearing, I havent seen one of those since my 78 F250 lol. Just the rear ujoint, and the rear driveshaft is on a slip joint into the rear of the transmission. It might be different with the manual tranny, but that is how my auto is anyway.

 

Thanks. I replaced the U joints on the driveshaft last summer due to some heavy vibration issues . The carrier bearing I left alone, might still need to replace it. I'll be opening the cover on the differential this weekend maybe.

 

It seems that there would always be noise if it was a bearing issue (whether it was accelerating or not). Regardless, lift up the rear and rotate those wheels by hand and check for noise coming from the wheel bearings. You can do the same thing by rotating your components (grab the driveshaft spin it, also spin each wheel) by hand and listen up close. I know it probably goes without saying, but be safe and use jack stands and chock your wheels.

Check the oil level and quality in the differential. Metal shavings can be an indicator. Don't be freaked out when you see some metallic dust/goo around the magnet in the differential.