I have recently notice a relatively quiet but constant grinding like noise while driving. It sounds like it's the transmission. It makes the noise in gear and also in neutral, however the really weird thing is that when I push the gear shift to the right (by 5th and reverse gear) the noise stops. But when it's in the middle or pushed to the left it still makes the noise. Any help is greatly appreciated.

Thanks

 

Its definitely the transmission, could be something in the shift shaft, tranny needs to come out to be diagnosed at that point best thing is a full transmission rebuild.

Edit: follow the shifter cables make sure everything looks good, make sure the bracket is good, make sure it's connected to the shift shaft correctly, look at it while someone goes thru the gears, drain the oil and inspect it, fill it with atf drive if for a few miles drain again fill it with the correct oil! And check again, while your at it do the same for the t case, if you feel is necessary.