Grinding noise in reverse gear only

Hi all I just bought an 04 trd with a 3.4l 5 speed and when you are in reverse gear going backwards it grinds. Only in reverse and only when moving backwards, if you take it out of gear and go backwards it stops. Any help would be appreciated!

 

All reverse gears make sort of a meshing/grinding sound. It is because reverse gears are straight cut rather than helical. The forward gears are helical cut which makes them quiet but slightly less strong, the reverse gear is straight cut and it is rather noisy. This is a common practice on many manual transmissions and even autos, on manuals it makes it damn near impossible to engage reverse while moving forward.

Here is a picture, the reverse gear (not the reverse idler) is straight cut while the forward gears are helical.

 

Is your truck a 4x4 or 2 wheel drive ?

 

4wd. It's a pretty bad grinding sound. The 1998 5 speed tacoma I had didn't grind this bad

 

Yes I understand the extra noise related to most reverse gears, this is actually a grinding noise

 

You need to get the truck on a lift with someone in the cab to put it in gear while you or someone searches for the grinding sound. I would stop driving it immediately until you figure this out. A $100 repair could turn into a $1000+ repair very quickly.

 

It shifts through the gears flawlessly. I agree it needs to be addressed soon though I was just wondering if someone had any insight as to what might be causing this

 

Did you ever figure out your problem?