Well, my truck (a 1996 Ram 1500 4x4 5.2L) started making a grinding noise when I let off the gas. The noise sounds to be coming from the rear and occurs when the truck is traveling over 30-35 MPH and I let off the gas. Also, once I put a little gas on, the noise stops. It just started a few days ago, and it is getting me worried (I have been braking with my other foot so I can leave a little gas on).


Any thoughts on what may be causing this?

 

I would check the fluid in the rear diff. Take a look back there and see if you can see an oil spot on it. If that's the case, then try taking off the cover and replacing the seals and then top it off.

 

If you are getting noises from your rear axle when you let off the gas there is a problem. You could have a bearing going bad or your contact pattern between the gears is shot. This is not going to be a cheap fix.

 

I checked under the truck and noticed a leak coming from the rear differential pinion seal, I will change the seal, refill the differential fluid, and see if I notice anything 'odd,' and I will report back.

 

Alright, I did a little more digging around online and under the truck (I have not changed the seals/fluid yet) and I am pretty sure that the truck has a worn out pinion bearing. So, I will be changing that. I will be sure to report back.

 

Sorry for the late report, but I had to order the parts online and had to wait for them to arrive. Anyways, I have replaced both the pinion bearings as well as new seals and fluid and the grinding noise is gone. I did notice some interesting things however. First and foremost, the pinion nut was extremely loose, I was able to take it off by hand. I think that that could have been a major part of the problem, and that torqueing it to spec could have fixed the grinding. But, I already had the differential taken apart and had the new bearings so I figured I might as well change them. I had some trouble getting the differential out of the pumpkin, however I did not know about the 'adjustable' shims that needed to be unscrewed to get it out, and after finding those (removed the entire axles and looked down the shaft) I was able to get it out just fine. I expected it to be a lot more of a difficult/expensive fix than it was, so it was nice to get it fixed for cheaper than I thought. Anyways, the grinding is gone and the truck is running just fine now.

 

My truck is doing the same thing and I have no idea what to do it was my grandpa's truck. He passed away a 1 or 2 ago and I don't know anything about trucks I'm learning as I go I love this truck and need it fixed ASAP 😭

 

8 year old thread. Prolly better if you start your own.

That said, Block the front wheels, jack up the rear, put the trans in neutral, (engine NOT running) and turn things by hand. See if anything stands out. Check the rear diff fluid as well.