I have a 2.8 with a T-5 behind, 1984 to be exact. It makes a grinding or quick vibrating noise in 1-3 gears when I have the clutch out but when I get into 4th gear, it is quiet as any other tranny should be and also when I have the clutch in. Do you have any idea what this could be? Also, when I am idling with the clutch out, it makes a rattling noise quite often, but when I put the clutch back in, it doesn't make the noise. Any ideas? The car has 127k on the stock drivetrain. Also, this may not have anything to do with it, but my starter is going bad and when I try to start it, it will turn over the engine very shortly, then it sounds like it just grinds and then I have to that a few more times to get it to start. I hope this is enough information.

Thanks,
Chris

 

I have not done a manual in years, but from what you are saying (4th being quiet) it sounds like a bearing is going away. The same things used to occur in Muncies & BW ST-10's.
Hope This Helps!!!