Slight vibration/rumble sound when letting off gas

[centex99]

So... 2007 v8 2wd, 164k miles... Transmission is a reman with < 5k miles/3 months ago.
Noise almost sounds like road noise but isn't. It's similar to the rumble strip sound that the light acceleration causes with the transmission (fly wheel/low fluid issues) but not quite the same. It's not nearly as loud or pronounced. It also only seems to happen when I let off the gas (vs slight acceleration with the other issue). Lastly, it only seems to happen around 70mph.
Any ideas on what it could be or anything I should check?

 

[bob60014]

Ring and pinion. Just repaired mine and it runs smooth, like new. Ymmv!!!!!

 

[centex99]

I just had a drive output seal replaced, but it was making this before that.
They said the old fluid was super black but clean from metal fillings.
I don't think I want to spend 800 to rebuild the difference for a slight noise, but will keep that in mind as a possible issue if it gets worse.

 

[chefduane]

Get up to speed 50mph+ then >carefully< shift into neutral. Rev the engine a bit. If it still makes the noise then it has to be engine related. If the noise is not present then its got to be drivetrain related. I had a similar issue on my previous '98 SOHC 4x. Turned out to be U-joints.

 

[FireFighter209]

I have this same issue on my explorer 96. It started out faint and just got worse. Like over 9 months I’d say. I’ve had a few mechanics look for it but none of them have identified the issue. I’ve pinned it down to a part in the TC via someone explaining an issue with the transfer case on YouTube. Unfortunately they didn’t specify the part name but I can say it has teeth and it’s suppose to interlock with another part. But the guy explained that the teeth break off over time. Which causes a metallic grind noise with a vibration through the gas pedal when it’s only released. I’m going to dig a little deeper here in a few days and figure out which part exactly. I’m sure it won’t be difficult, for reference I have the borg Warner 4405 TC.

 

[Mrobs146]

I have this same issue on my explorer 96. It started out faint and just got worse. Like over 9 months I’d say. I’ve had a few mechanics look for it but none of them have identified the issue. I’ve pinned it down to a part in the TC via someone explaining an issue with the transfer case on YouTube. Unfortunately they didn’t specify the part name but I can say it has teeth and it’s suppose to interlock with another part. But the guy explained that the teeth break off over time. Which causes a metallic grind noise with a vibration through the gas pedal when it’s only released. I’m going to dig a little deeper here in a few days and figure out which part exactly. I’m sure it won’t be difficult, for reference I have the borg Warner 4405 TC.

Did you ever figure it out? I’m having an issue where when I let off the gas at higher speed I can feel it feels like it girps and let’s go. I also have vibration in steering wheel 50-70mph