Grinding noise

[HennaE30]

So my car developed a grind/scrape noise while coasting. For example, accelerating through 3rd gear, get up to 3000rpm and then get off the gas and it scrapes until you go back on the throttle or press in the clutch. It is RPM dependant.

We thought it was an input shaft bearing, so we swapped trans on it. It got a new clutch kit and rear main seal, put it all back together and it is still making the noise.

After lifting it back up and looking at it, we noticed the front diff mounting bolts were missing. Could this be whats causing the noise? and what could the driveshaft/halfshafts be rubbing on? so i know to check for damage.

Thanks,
Nick

[Hooffenstein HD]

After lifting it back up and looking at it, we noticed the front diff mounting bolts were missing. Could this be whats causing the noise? and what could the driveshaft/halfshafts be rubbing on? so i know to check for damage.

Thanks,
Nick

I'd say putting some bolts in would be a good start. The sound may be the uni joints or centre bearing disintegrating, it may not necessarily be rubbing but if it was, it would likely be where it passes through the rear sub frame.

[HennaE30]

I'd say putting some bolts in would be a good start. The sound may be the uni joints or centre bearing disintegrating, it may not necessarily be rubbing but if it was, it would likely be where it passes through the rear sub frame.

Alright I'll definitely look there.. I have no idea how the managed to back themselves out, especially since they go in from the top. Got new hardware that I'm going to throw in there tomorrow.

[Hooffenstein HD]

Use studs and nuts and Loctite.

[Gnarles]

If you hear it when letting off the gas or coasting in gear, it could be the pinion bearing in your diff going out.

[HennaE30]

The new hardware fixed the issue. Thanks guys.