My car whines in all gears but worst in 5th. It has a Locked 4.65 diff. Is turbo'd and generally has a pretty hard life. The box still shifts great and seems fine but it sounds like I have straight cut gears.

I'm trying to figure out if it's the gearbox or diff that's whining.

If I drive along and let it coast in gear it still whines but If I depress the clutch whilst still rolling along the whining stops. Obviously the cars rolling weight is still spinning the diff which in turn is still spinning the gearbox.

This would suggest to me that there is some sort if wear to the gearbox input shaft.

Does this sound correct?

 

Sounds quite a lot like this


Maybe not quite that bad but pretty close.

 

Whining in a straight-throug gear (4th on a 5speed, no gears are loaded) means the diff.

 

Really? Awesome. I'll try it in 4th to be sure but I'm pretty sure it whines in all gears.

Thanks

Edit: sure that's correct? Surely even if it in a straight through gear if the input shaft bearing was worn it would still whine?

 

Gear whine and a bad bearing would sound different.
Your funky diff is a suspect regardless.

 

A worn out input shaft can make it hard to shift into third at least from my personal experience. My spare transmission has bad input shaft play n that's the only thing besides sounding like it needs a throwout bearing real bad. Almost sounds like motor knocking.

 

that sounds like a definite throw out bearing

 

I've had this issue It was especially annoying at low speeds and lower gears.